2014 AAPM Spring Clinical Meeting ‐ Abstracts

Methods Using scan data acquired with several detectors including an IBA CC13, a PTW 60012, and a Sun Nuclear Edge detector, three complete beam models are created, one for each respective detector. Next, using each beam model, dose volumes are retrospectively recalculated from actual anonymous patient plans. These plans include three full-arc VMAT prostate plans, three left chest wall plans delivered using irregular compensators, two half-arc VMAT lung plans, three MLC-collimated static-field pairs, and one SBRT liver plan. Finally, plans are reweighted to deliver the same number of monitor units, and mean dose to target volumes and organs at risk are calculated and compared.


Purpose
To accurately measure the field output factors (OF) for photon beams from a 6 MV medical accelerator for small photon fields up to 10 cm × 10 cm.

Methods
Two diode detectors and three ionization chambers are each separately placed inside a scanning water phantom at two different positions: source-to-surface-distance (SSD) of 100 cm at a depth of 10 cm and at SSD of 95 cm at 5 cm depth. The photon field is collimated either by the jaws or by the multileaf collimator (MLC). Regression analysis and analysis of variance are applied to the OF data versus detector volume for the 1 cm × 1 cm field size.

Results
For square fields of width greater than 3 cm, OF measurements from the detectors agree to within 1% or less. The largest variation in OF occurs for the 1 cm × 1 cm field size, observed at any depth, SDD, and field collimation. For jaws-shaped field, a difference of more than 18% is observed between the diode detector and the ionization chamber of the biggest volume. Additionally, there is a positive correlation between OF and detector sensitive volume where the regression coefficient is greater than 0.75 for all cases.

Conclusion
Measured OFs are found to depend upon the field size, SSD, depth, and also upon the type of beam collimation, size, and type of detector used. The OF variation is maximum at small field sizes and when the detector volumes are orders of magnitude different. For a 5% significance level, where at least five detectors of different types are used in the OF measurements, the correlation between the OF and detector sensitive volume can be used to arrive at a corrected OF value at 1 cm × 1 cm field size.

Purpose
Bolus materials are commonly used to correct the depth of maximum (dmax) radiation dose deposition to the patient's skin surface. Brass mesh has been used as a substitute for Superflab or wet washclothes because it conforms to skin contours readily. A comparison study was conducted to determine how many layers or brass mesh would equate to 0.5 cm of water-equivalent bolus for low-energy photons and electrons.

Methods
Superficial doses (0-5 mm depth) for Superflab, wet washcloths, and varying layers of brass bolus were measured with a parallel plate ion chamber in a Solid Water phantom. With the surface of the phantom set to 100 cm SAD, electrometer readings of the bolus materials were compared and analyzed with 0.5 cm of solid water.

Results
For 6 MV and 10 MV photons, three wash cloths and three layers of brass mesh produced skin doses that were within 2.4% and 5.1%, respectively, of solid water measurements. Superflab measurements were within 1.1% of solid water. In 6 MeV, 8 MeV, and 10 MeV electrons, one layer of brass mesh demonstrated a better match of skin doses in 0.5 cm solid water or Superflab. The percent difference in one-layer and two-layer brass mesh readings compared to solid water were -0.87% and 13.7%, respectively. The difference between Superflab and solid water was less than 1%.

Purpose
Automating evaluation of radiation therapy treatment plans for agreement with protocol constraints can reduce the time spent planning. Creating a treatment plan based on a protocol can be time-consuming for dosimetrists due to the rigid dosimetric constraints which should be met. These values are typically gathered manually from the treatment planning system (TPS). If a dose constraint is not met, adjustment of the plan to meet one constraint requires rechecking of other constraints. This must be done in an iterative manner to meet all constraints.

Methods
RTOG protocols 0915 and 0813 (peripheral and medial lung SBRT) require documentation of over 40 volumetric and dosimetric values. Scripts were developed in-house that report contour volumes, create isodose contours, perform operations on contours, report region-of-interest (ROI) dose coverage, and report prescribed and maximum doses to ROIs. The results are reported immediately in a simple text document on the TPS computer. Included in the report are the current plan's values, the limit for each constraint, and a pass/fail indication for each.

Results
Our current suite of scripts differs from existing solutions in both speed and capabilities. Third party DVH evaluation software requires export of contours and DICOM dose data, a cumbersome extra step. Our scripts have capabilities that go beyond current TPS limits, including creating isodose level contours, then performing Boolean operations on those contours. This is necessary for measuring the volume of the 105% isodose level outside the PTV. Additionally, our scripts can handle constraints which vary according to plan parameters. In both RTOG 0915 and 0813, the low dose spillage limits vary in steps according to tabular values of PTV volume.

Conclusions
Our experience shows that automatically evaluating plans reduces planning time. Our scripts allow a faster and more complete evaluation than existing solutions.

Purpose
To assess interfraction positional variation in pancreatic tumors using daily breath-hold conebeam computed tomography at end-exhalation with visual feedback (BH-CBCT).

Methods
Six consecutive patients with pancreatic cancer who underwent BH intensity-modulated radiation therapy with visual feedback were enrolled. All participating patients stopped oral intake with the exception of drugs and water for > 3 h before treatment planning and daily treatment. No patient was provided oxygen. Each patient was fixed in the supine position on an individualized vacuum pillow with both arms raised. The prescription dose was 45 to 51 Gy in 15 fractions. An isotropic margin of 5 mm was added to create the planning target volume. BH-CBCT scans were performed before beam delivery in every fraction. BH-CBCT acquisition was obtained in three or four times breath holds by interrupting the acquisition two or three times, depending on the patient's BH ability. The image acquisition time for a 360° gantry rotation was approximately 90 sec, including the interruption time due to BH. The initial setup errors were corrected based on bony structure, and the residual errors in the target position were then recorded. The magnitude of the interfraction variation in target position was assessed for 90 fractions.

Results
The systematic and random errors were 1.5 and 2.1 mm, 1.2 and 1.8 mm, and 0.3 and 2.7 mm in the left-right, anterior-posterior, and superior-inferior directions, respectively. Absolute interfraction variations of > 5 and > 10 mm were observed in eight (8.9%) and two (2.2%) fractions, respectively.

Conclusion
BH-CBCT with visual feedback provided high pancreatic tumor position reproducibility. However, absolute interfraction variations of > 5 mm were occasionally observed. Therefore, target matching is required to correct interfraction variation, especially to ensure safe delivery of escalated doses to patients with pancreatic cancer.

Evaluation of Deterministic Grid-Based Boltzmann Equation Solver for Dose Calculation in Endobronchial
High-Dose-Rate Brachytherapy M Axente, 1 * S Wetherall, 2 B Loo, 1 A Sung, 1

Purpose
To evaluate the use of deterministic grid-based Boltzman (GBB) equation solvers for dose calculation in HDR endobronchial brachytherapy.

Methods
Three lung cancer patients CTs and a virtual phantom composed of a 30 cm³ block of lung with a 1 cm diameter central water column were used in the evaluation of dosimetric differences between TG-43 formalism and BrachyVision (v.13) Acuros GBB solver. Materials were manually (phantom) or automatically assigned, based on the CT values (patients) from the Acuros library for inhomogeneous dose calculation. TG-43 dose to water and Acuros dose to medium were calculated for both patient and phantom studies. The difference between the two dose distributions was calculated across the calculation matrix, and normalized to the local TG-43 dose. For patient studies, DVH parameters (target and OARs) were also compared, including mean doses for 1 mm lung tissue shells created at 2 cm and 5 cm from target.

Results
The phantom study indicates relative spatial differences between the two dose distributions, especially along the long axis of the source, where differences in excess of 40% can be observed. TG-43 is shown to overestimate the dose in the vicinity of the source, and underestimate the dose relative to Acuros past an inflection point away from the source in lung tissue. In the plane perpendicular to the source, TG-43 dose is 5% higher within 2 cm of the source. Similar spatial differences in the dose distribution are observable in the patient cases. Mean dose to medium in the lung shells indicate differences up to 5% higher (5 cm) and up to 2.2% lower (2 cm) than TG-43. Absolute dose differences are minimal as indicated by DVH parameters similarity.

Conclusion
TG-43 and Acuros calculated dose distributions are spatially different. Since the absolute dose differences are minimal, their clinical significance remains to be further investigated.

K Wang 1
Johns Hopkins University School of Medicine, 1 Baltimore, MD, Elekta Oncology Systems, 2 Atlanta, GA

Purpose
The accurate measurement of radiation isocenter (radiso) of a linear accelerator is critical and will impact the quality of radiation therapy. Traditional quality assurance (QA) procedure focuses on the measurement of single radiso, usually of 6X photon beam. Due to different flattening filters and steering parameters, the radiso of one energy mode can deviate from another if no special efforts were devoted during machine acceptance/commissioning phase. We presented a procedure of determining the multiradiso alignment of megavoltage (MV) with submillimeter accuracy using EPID-based imaging method.

Methods
An 8 mm ball bearing (BB) phantom was placed at the 6X radiso based on EPID images at various gantry and collimator angles. The 3D radiso shifts of other energy modes relative to 6X were determined. Beam profile scanning was used as an independent method to determine the 2D multiradiso alignment among flattened and flattening filter-free (FFF) mode (6X, 10X, 15X, 6XFFF, and 10XFFF). To further quantify the impact of radiso offset on the target positioning accuracy, 10X radiso was manually offset from 6X by adjusting the bending magnet current, and the corresponding deviations of table rotation axis, aligned to 6X radiso, as well as the maximum deviation of the BB centroid during table rotation from the 10X radiso, were assessed.

Results
From the EPID-based method, we identified the 10XFFF was 0.96 mm/0.35 mm away from 6X radiso before/after tuning the beam steering parameter, which was confirmed by profile scanning method. The maximum deviation of BB phantom from 10X radiso was observed to linearly increase with the offset between 6X and 10X radiso; 1 mm 10X radiso offset translated to 1.8 mm deviation of BB phantom centroid ("target") from the 10X radiso.

Conclusion
We first investigated the relative multiradiso displacements of MV photon beams. The alignment of the multiradiso is particularly important for high-precision radiotherapy techniques.
Garth Cowan is an employee of Elekta.

Purpose
To provide the medical physics community with the experience of the University of Florida Health with obtaining dental cone-beam CT (dCBCT) accreditation from the IAC.

Methods
The CMS requires dentists to have advanced diagnostic imaging CT accreditation to claim Medicare reimbursements. Due to the infancy of dCBCT accreditation, it is important that experiences in this area are shared among the medical physics community. The IAC standards are generally divided between organizational and CT testing components. Of great interest to the medical physics community are the requirements for routing QC testing, which is addressed in IAC Accreditation Standards Part II, Section 2. The only test required is dose assessment, and no standards are given for any test. The units tested were the Kodak CS 9000 and 9300 and iCAT units. Manufacturer supplied phantoms and the Gammex 464 CT phantom were used for all testing.

Results
The tests selected for annual evaluation were exposure linearity, slice thickness, artifact assessment, high contrast spatial resolution, image uniformity, and dose assessment (using both the AAPM Report No. 111 and less desirable CTDIvol methods). The most frequently used protocol was selected for each test. Exposure linearity had a COV less than 0.05 for all units. Minimum high-contrast spatial resolution was 6 lp/cm. Pixel value deviation was no more than 166 from the center of a uniform image for all units. The greatest CTDIvol was 5.2 mGy, and the AAPM Report No. 111 method yielded point-dose values close to the CTDIvol values obtained.

Conclusion
UF Health used these tests for initial application for IAC accreditation for dCBCT, and other institutions may use this as a starting point for their own accreditation applications. As more institutions become accredited and dCBCT standards are set, a more unified approach to dCBCT accreditation will be established.

Purpose
Intracerebral hemorrhage (ICH) is one of the major devastating forms of stroke. This disease currently does not have viable treatment options. Diffusion tensor imaging (DTI) records fractional anisotropy, which measures the degree of directionality in the diffusion process of water using a scale from 0 to 1, where 0 is equivalent to diffusion in all directions and 1 represents diffusion in a single direction and restriction in all others. Mean diffusivity measures the amount of diffusion. Disintegration of the CST is represented by a lower FA value and higher MD value.

Methods
We have retrospectively collected multiple MRI scans of patients (with approved IRB protocol) admitted into our hospital from the past one year and have their MRIs between week 3, 6 after the occurrence of ICH with a DTI sequence on a 3-Tesla GE scanner. We obtained FA and MD data on the cortical spinal tracts by drawing ROI on the cerebral peduncle, internal capsule, and pons of both ipsilateral and contralateral to the hematoma. The ROIs were used to calculate FA, MD, and volume. The correlation of FA, MD, and volume s were evaluated.

Results
We obtained data on nine patients with basal ganglia hemorrhages. Preliminary analysis demonstrates that lower FA values correspond to worsening outcome and increased motor deficits. On week 3 and 6 FA of the cerebral peduncle on the affected side had direct correlation with worsening outcome and the correlation coefficients are 0.7 and 0.8, respectively. Additional data are needed to investigate further.

Conclusion
ICH is a devastating disease with no approved medical therapies. These data may be an important biomarker that allows clinicians to monitor patient recovery and provide insight on Purpose Development of the human vasculature database including femoral arterial parameters like maximum femoral artery diameter (MFAD), length, branching angles, etc., for both men and women will be critical for peripheral arterial disease (PAD) diagnosis for a treating clinician. Sporadic or limited work has been reported in clinical/preclinical research till date. This work was an important effort towards the development of human vasculature database using our newly developed method for estimation of stenosis-Ref.

Methods
Patient exams were performed under an IRB-approved protocol. Raw MR angiographic images of 30 male and 30 female PAD patients were retrospectively processed and analyzed for MFAD. The measurement includes healthy, as well as symptomatic, regions of interest at different femoral arterial sections. MR angiographies with 1 mm 3 spatial resolution were used for this work. Clinical exams were acquired on 3.0 T GE scanners.

Results
Data analysis: The angiogram was postprocessed using tree analysis and virtual endoscopy modules of Analyze 11.0 software to fly through the femoral artery. A statistical parameter called brightness area product (BAP) was defined as the sum of the intensities above the sample minimum intensity/threshold set by the user. This BAP is treated as a metric for the assessment of degree of stenosis. Different parameters were tested using two-way Anova Student's t-test.

Results and Discussions
A statistical significance (p < 0.05) has been noticed for MFAD and linear arterial measurements among men and women for both healthy and symptomatic sections of the peripheral artery. More work towards the development and validation of this study is under progress.

Purpose
Common methods for commissioning linear accelerators tend to neglect beam data for very small fields. An examination of the methods of beam data collection and modeling for commissioning linear accelerators revealed little to no discussion of the protocols for fields smaller than 4 cm × 4 cm. This leads to decreased confidence levels in stereotactic radiotherapy (SRS). Accuracy in the calculations of the TPS is the foundation of high-quality external-beam radiation therapy outcome and improved patient care.

Methods
AAPM TG-155 is making several recommendations to improve the measuring process. These include the use of scanning water tank to increase the central alignment of the detectors, and using multiple detectors to confirm the accuracy of the measurements. Another area of improvement is replacing the protocol of using equivalent squares and interpolation to complete the output factor matrix with effectively measuring the output factor of each rectangular field. The output factors were completed by direct measurements only. Three areas of are addressed: detector alignment, actual measurements, and confirming the accuracy using a second type of detector. These improvements in the measurement process exhibit a marked improvement in the accuracy of the absolute dose calculated by the TPS.

Results
The treatment planning system (TPS) is an essential tool in any radiation therapy treatment. The specific capabilities of one TPS to another may differ, but the fundamentals are the same. Applying the above methods improved the accuracy of the SRS plans by 18% in dose accuracy calculation to delivered.

Conclusion
Improving the methods of collecting output factors led to an increase of confidence levels in the absolute dose delivered. Changes in the way we use the modern linear accelerator mean changes in the way we collect and commission the data. These methods improve the overall outcome, thus improving patient treatment outcome and care.

PO-BPC-Exhibit Hall-19
Dosimetric Impact of Roll Error on Lung Cancer Treatment Plan in Uniform Scanning Proton Therapy S Rana* ProCure Treatment Centers, Oklahoma City, OK

Purpose
The purpose of this study is to investigate the dosimetric impact of roll error on the lung cancer treatment plan in uniform scanning proton therapy.

Methods
Computed tomography (CT) dataset of lung cancer case treated with uniform scanning proton therapy was selected for this study. Proton plan for this case was generated using two fields. In order to observe the roll error on the dosimetric values, the CT dataset was resampled introducing various roll angles. A total of eight new CT dataset was generated for roll angles ranged from -10° to +10° with an increment of 2.5°. In the next step, eight new proton plans were generated based on the resampled CT dataset using the beam parameters identical to ones in the original proton plan. Dosimetric values from new proton plans were compared with that of original proton plan for the PTV coverage (dose received by 95% of PTV volume), maximum dose (Dmax) to the spinal cord, and the relative volume of total lung receiving at least 5, 10, and 20 CGE (V5, V10, and V20, respectively).

Results
The relative difference (Δ) in the PTV coverage between the original and new proton plans ranged from -0.03% to -29.77%. For total lung, dosimetric values were always smaller for plans with roll angles +2.5° to +10°, whereas the Δ ranged from -4.63% to +2.11% for roll angles -2.5° to -10°. For the Dmax of the cord, the Δ ranged from -14.47% to +15.19%.

Conclusion
The preliminary data from this study suggests that roll error of more than 5° could produce unacceptable decreased PTV coverage and increased Dmax to the cord for lung cancer in uniform scanning proton therapy.

Purpose
To investigate the feasibility of replanning due to air cavity effect for accelerated partial breast irradiation (APBI) brachytherapy.

Methods
Dosimetric data of six patients treated with Contura multilumen balloon were retrospectively assessed for adaptive planning. Two axial CT image datasets were acquired; one was CT simulation used for planning and the other was prior to the first treatment. Ribs, skin (2 mm skin rendering), air cavity, and PTV_EVAL following NSABP B-39 protocol were contoured on both CT datasets. Plans were generated using criteria including, for PTV_EVAL, V90PD (volume received 90% of prescribed dose (PD)) ≥ 90%; V150PD < 50cc; V200PD < 10 cc. For skin and rib, Dmax (0.1 cc) (maximum dose) < 125%PD. Dosimetric effect due to air cavity was evaluated by recomputing dose distributions on the second CT dataset by applying the same dwell planning time and comparing to the original plan. Differences were assessed for statistical significance (p < 0.05) using Student's t-test.

Results
50% of patients had an average 1.4 cc air volume decrease between planning and treatment day. As a result, the average maximum skin dose increased by 18.7%. Similar dosimetry effect was discovered as the air cavity shown near the rib. The air volume decreased by 1.7 cc causing the maximums rib dose change by 15.5%. Overall, there was no statically significant difference in target dosimetery (V90PD, V150PD, and V200PD) due to change in air volume.

Conclusion
Our study demonstrated a correlation between air volume change with skin and rib dose. Consideration of pretreatment 3D CT image acquisition and replanning is suggested when a significant change in air volume detected near critical structures.

Purpose
Accurate targeting of the tumor volume is crucial to the success of radiotherapy treatment and is of particular importance in hypofractionated treatments such as stereotactic body radiotherapy (SBRT). For many patients, especially those whose tumors exhibit motion due to respiration, alignment by orthogonal imaging and CBCT alone is not ideal. For these patients we use aperture gating on our TrueBeam sTx with Perfect Pitch couch. This work verifies the necessity of aperture-based treatment.

Methods
The TrueBeam STx with HD-MLC and Perfect Pitch couch is ideal for treatments requiring a high degree of accuracy and precision. A 4D CT is used to determine the exhale phase and delineate the respective margins due to respiratory motion. Fiducial markers, such as gold seeds or stents, are used as a surrogate to determine the position of the PTV during treatment. A beam's-eye-view (BEV) aperture is created in a fluoroscopic setup field and used to determine the respiratory gating window at treatment. Initially, the patient is first aligned with orthogonal kV imaging. kV images are also acquired for during-treatment verification. To verify the accuracy of this method, a plastic water phantom is placed on a moving platform to simulate the treatment. This method has been verified using EDR2 film and phantom measurement. Targets of various sizes were used.

Results
During treatment, intrafraction kV images were taken at every beam on cycle for target positioning verification. Images can be taken at the beginning or at the end of the beam-on cycle. Film measurement confirmed the accuracy of the treatment to a target size as small as 1 cm diameter.

Conclusions
The aperture-gated method allows a potential reduction of the treatment margin to less than 5 mm for lung SBRT and for liver or pancreas SBRT a margin of 2 mm could be used.

Mayo Clinic Rochester, Rochester, MN
Purpose DWI is the current standard to identify and manage stroke. We assessed the hypothesis that resting state fMRI may detect the infarcts in patients with acute ischemic stroke more effectively than DWI.

Methods
We studied ten patients within seven days of the acute onset of stroke patients retrospectively with an approved Institutional Review Board. All patients underwent multimodal MR imaging, including DWI and resting state fMRI sequences in the using a GE 3T MRI scanner. High resolution T2-weighted images were also acquired. The resting state fMRIs were processed using a published method by a single rater with extensive experience in neuroimaging data processing to avoid interrater variability. DWI data was analyzed using Analyze 11.0 software.

Results
fMRI provides more accurate information on the irreversible status of ischemic brain tissue during an acute stroke compared with diffusion weighted imaging. Similar results were observed across all the four patients studied.

Conclusion
The results of this project have direct clinical implications. fMRI show areas of damage when DWI has normalized after an acute ischemic stroke. DWI can normalize after showing an area of restricted diffusion in areas of the brain that is irreversibly injured. Therefore, fMRI reliably indicates damaged brain tissue in the setting of acute ischemic stroke where DWI is unable to detect. Such information is critical to make treatment decisions when considering which acute stroke patients should undergo reperfusion therapies. fMRI provides complimentary information to CT/MRI perfusion and has the potential to obviate the need of CT/MRI perfusion which are invasive, and time and resource intensive. Our study is limited by their qualitative nature and small sample size.

Localization for H&N Patients who Undergo Rescans: A Case Study
L Courneyea,* D Pafundi

Purpose
Study the necessity of creating new references images after a patient is resimulated.

Methods
A retrospective case study was evaluated for the impact of forgoing new reference images for patient localization after a rescan. The patient studied underwent two rescans during a course of treatment. The first rescan was prompted by the removal of a Precise Bite from the patient's immobilization. The second rescan occurred after a new mask was created. To determine the impact of updating the reference images on the ability to accurately align the patient in an acceptable time, pretreatment CBCTs were matched to each of the three CT scans. The matches were performed using the automatching tools in Aria to a structure that contained the mandible, occipital bone, C1/C2, and C7/T1. The matches between the daily CBCTs and the three simulation scans were assessed for agreement of each of these structures using margins of 3 mm and 5 mm. The stability of the match was also tested by checking if the match changed when the algorithm was re-run.

Results
The accuracy of the automatch was strongly dependent on the CT set used. The structure which maintained the highest accuracy was C1/C2. When the CT and CBCT immobilization were the same, C1/C2 was matched to within 5 mm for 94.3% of the fractions. This decreased to 81% with a change in Precise Bite, 50% with a change in mask and 0%, if both items were changed. The stability of the match also decreased when changes were present.

Conclusion
When a new mask is created, new images are essential for proper alignment. For the removal of a Precise Bite, the need for new images is dependent on site and the acceptable margin of error. Unstable matches were found to be an indication that new images are required.

Purpose
Intraoperative electron radiation therapy (IOeRT) is one of the developed technologies uses mobile linear accelerators for postresection patient treatment offers flexibility inside the operating room (OR). The overall implementation process of IOeRT is discussed here.

Methods
The IOeRT delivering mobile linac equipped with electron energies 6, 9, and 12 MeV is warmed up with 500 MUs for each beam in the morning of the patient treatment. The dose output, energy ratio and some of the safety tests are performed by a radiation physicist. The IOeRT candidate patients are resected in OR followed by a possible single fraction electron dose to the tumor bed to treat residual disease.

Results
Out of 11 patients treated to date, 30-to-75-year-old, ten male and one female, almost 75% will be receiving postsurgical chemotherapy. Along with pancreatic, retroperitoneal para-aortic, urinary bladder treatment sites, almost half of the sites were portahepatis lymph nodes (LNs) and celiac LNs. A separate work is in process of compilation of pathological data. The single fraction doses ranging 10 Gy to 20 Gy were delivered using cones of mixed bevel angles 0°, 15°, and 30°, diameter ranging 6 cm to 10 cm with 0.5 cm bolus used in almost every treatment. The radiation therapy was delivered successfully as per clinical protocols, including AAPM TG-72 guidelines. The pathological data analysis is in compilation stage for further analysis. The clinical outcomes would be presented separately after clinical follow-up data are available in coming months.

Conclusion
The IOeRT with high-energy and high-dose rate electron beams is a viable modality for pelvis and abdominal regions.

Purpose
To experimentally verify skin-to-center dose (SCD) ratios using optically stimulated dosimeters (OSLD) to provide relative measurements in high-dose-rate surface brachytherapy of the breast.

Methods
OSLDs calibrated using 6 MeV X-rays were used to perform phantom-based measurements with Accuboost applicators using an Iridium-192 high-dose-rate source. Measurements were performed at the surface and center of phantoms of various thicknesses using several applicators in order to provide measured SCD ratios specific to each applicator and phantom thickness. Measured SCD ratios were then compared to vendor-provided MCNP data. Additional measurements were made using a phantom to simulate a patient treatment in order to estimate the maximal SCD ratio.

Results
Comparison of the experimental results for SCD ratio with those generated using MCNP produces good agreement. The results also provide estimates of the relative contribution to skin dose from orthogonal beam pairs allowing for the estimation of a net SCD ratio for the entire treatment when orthogonal beam pairs are used.

Conclusion
These results provide experimental verification of the vendor-provided SCD ratios and provide estimates of the maximum SCD ratios that can be expected when orthogonal beam pairs are used clinically.

Methods
18 patients with thoracic esophageal carcinoma (the upper, the middle, and the lower thorax were six cases, respectively) were selected to design IMAT and VMAT treatment plans on Varian clinical 23IX conventional linear accelerator and Elekta Synergy new generation linac, respectively. Prescription dose of 60 Gy in 30 fractions, planning objectives for PTV were at least 95% reached the prescription dose and V110 no more than 10%. The maximum dose of spinal cord below 45 Gy and lung's V5 ≤ 55%, V20 ≤ 28%, V30 ≤ 18% were constrained. PTV and tissue dose-volume parameters, machine MU, treatment time and γ pass rate were compared. Using SPSS 19.0 software paired t-test analysis two sets of data.

Conclusion
IMAT in the treatment of time and tissue of high-dose irradiated area is less than that of VMAT; but machine MU and tissue of low-dose irradiated area is higher than that in VMAT. These two treatment methods can meet the clinical demand, can be selected according to the actual situation of the patient treatment.
The scientific research foundation of Hebei Provincial Health Department (project number: 20130253) This session will provide a refresher of RSO requirements and responsibilities under both regulatory and accrediting bodies. It will span radiation oncology, nuclear medicine, and radiology, as well as the expanding charges of the Radiation Safety Committee. In most hospitals, the RSO is a physician-authorized user who relies heavily on the consultant medical physicist to supply guidance and analytic assessment to ensure regulatory compliance. Often the Medical Physicist may be asked to address radiation safety issues outside their normal scope of practice.  2 Aurora, CO, The Ottawa Hospital Regional Cancer Ctr., 3 Ottawa, ON Treatment planning systems are indispensable for the radiation therapy treatment process. Despite the various versions implemented within different commercial systems, dose calculation algorithms generally share the same fundamental physics and can be separated into several categories. This session will review modern treatment planning algorithms, including convolution/ superposition and Monte Carlo. For each algorithm, we will go through the physics behind the dose calculations and discuss the clinical implementation considerations. We will review their limitations and accuracies. We will discuss commissioning requirements for these algorithms and provide clinical examples with treatment plans.

Orlando Regional Healthcare System, Windermere, FL
This presentation briefly introduces RadSite to the medical physics community and explains our accreditation program that was approved by the Centers for Medicare and Medicaid Services (CMS) as meeting the requirements of the Medicare Improvements for Patients and Providers Act (MIPPA). The history of RadSite is reviewed, and the accreditation program requirements for imaging and safety policies, equipment, clinical examinations, and physics testing are explained. Special attention will be given to the physics testing requirements portions of the accreditation standards.
Learning Objectives: 1. Review the RadSite accreditation process. 2. Review clinical requirements of the accreditation process. 3. Discuss the Medical Physicists role and responsibilities for RadSite accredited facilities.

Columbia University Medical Center, New York, NY
This presentation briefly introduces carotid artery stenting (CAS) and the IAC. Carotid artery disease causes about half of all strokes. The two major invasive treatments are surgery or stenting. CAS is performed using an interventional fluoroscope. The goal of IAC in this domain is to facilitate optimizing the safety and efficacy of CAS. Medical physicists play a key role both in image optimization and in radiation management. The standard includes requirements for equipment, safety, and physics testing. Data are required for both the initial application and for periodic quality management. The standard's requirements exceed those needed to minimally comply with most radiation regulations. One goal of IAC is to integrate QMPs into the CAS environment as active contributors. The presentation will review relevant portions of the standard, and provide a sampling of topics that the QMP might consider implementing in this role.
In the medical physics realm, the mention of "quality assurance" (QA) is often associated with topics such as system commissioning or per-patient verification of TPS dose calculations and machine delivery. However, in reality, a total quality system has many more components. One vital upstream component is the quantification and assessment of the actual "plan quality" (i.e., the abilities of the TPS, modality, and treatment planner to create high-quality plans that meet clinical needs and are robust with respect to potential errors). The quantification and study of plan quality across many TPS, modalities, and treatment planners has been the major point of study for a group of clinicians and researchers for the past few years. They will describe the methods, experiences, and lessons learned. Scientific studies of plan quality variation (and the root causes) will be presented, and a dedicated "Plan Challenge" on a challenging SBRT case will be performed just for this meeting. Another topic will introduce plan quality measures as a key component in a Maintenance of Certification (MOC) project at a large clinic. Yet another talk will concentrate on the role of plan quality measures in the evolving recommendations for TPS commissioning and will provide a glimpse into the upcoming TG 244 report. The session will close with discussions of practical implementation, automation, and application to commissioning new autoplanning software tools, plus other future directions to further improve radiation plan quality and safety going forward.
Learning Objectives: 1. To learn the history and methodology to create comprehensive and customizable plan quality algorithms.
2. To learn the measured variations in plan quality based on: treatment planner, TPS, and delivery modality. 3. To understand the difficulty to achieve any/all physician's objectives prior to planning (but postcontouring) and realistic expectations prior to plan optimization. To learn how to do patient-specific adjustments, or normalizations, of plan quality scores. 4. To learn a comprehensive plan quality metrics for a MOC project. 5. To discuss standard sets of clinical plans (patient data) for TPS QA along with a clear list of aggressive, multicriteria plan objectives, with the goal to be to quantify and benchmark. 6. To learn the results of the Plan Challenge planned and dedicated specifically for this AAPM meeting.  With the proliferation of CT scanners and increasing interest in accreditation, many physicists are being asked to support facilities seeking IAC CT Accreditation. IAC CT Accreditation is particularly attractive to facilities utilizing small field of view cone-beam CT (CBCT), such as ENT and dental practices, since these scanners cannot image larger size phantoms required for ACR Accreditation. This presentation addresses the specific IAC requirements for medical physicists supporting sites seeking IAC Accreditation. Some of these requirements are unique to IAC CT Accreditation, and will be addressed in detail. Common weaknesses in facility submissions relating to medical physics services will be presented. An overview of the IAC organization, Standards and the actual process of becoming accredited will also be presented. The relationship between the medical physicist and radiologist has grown in importance in the present regulatory environment, and is advocated for in the recently released AAPM Medical Physics Practice Guideline 1.a: CT Protocol Management and Review Practice Guideline. Collaborative patient image review is an important mechanism to facilitate dialogue about dose optimization and clinical requirements. Clinically significant diagnostic challenges with medical vignettes and patient images will be presented. This session will include details surrounding an important accreditation body and modality, and critical considerations in the ever-developing paradigm of the patient dose and image quality continuum with respect to collaboration between clinicians and medical physicists.

CT IAC Accreditation / Clinical CT for Physicists
Learning Objectives: 1. Review the IAC CT Accreditation program and typical facilities seeking accreditation. 2. Review relevant Medical Physics processes and responsibilities unique to IAC CT Accreditation. 3. Review common problems with medical physics reports submitted to IAC CT Accreditation. 4. Review the process of applying for IAC CT Accreditation. 5. Observe pathology-mimicking artifacts in head CT. 6. Review image characteristics necessary for accurate diagnoses in spine CT. 7. Review expectations for screening, nonscreening, and specialty chest CT. 8. Observe image features that create challenges for lesion detection in liver CT.

SA-D-Salon AB-01
Image Registration for Radiation Therapy Applications D Wang, 1 * P Balter 2 *

University of Iowa, 1 Iowa City, IA, UT MD Anderson Cancer Center, 2 Houston, TX
Image registration is an indispensable process for radiation therapy, involved in both treatment planning and image guidance at treatment. For treatment planning applications, this session will review multimodality image registrations between treatment planning CT and 4D CT, MRI, PET image set, as well as CT and dose map from previous treatment, if available. For each modality, we will discuss the clinical implementation considerations. We will also discuss deformable image registrations. For image-guidance applications, we will discuss registration between CBCT and treatment planning CT image sets. We will review the limitations and accuracies of the registrations. We will discuss the clinical considerations of selection of region of interest (ROI) and provide some clinical examples. We will also discuss the compromises needed for daily IGRT and how these are communicated among the treatment team. Clinical diagnostic medical physicists may be responsible for implementing and maintaining a comprehensive MR safety program. Hospitals and clinics will look to the physicist to not only understand guidelines, regulations, and accreditation requirements related to MR safety, but also to understand details related to patient care and employee safety. Accrediting bodies including the ACR, IAC, RadSite, and the Joint Commission each include aspects of MR safety into their imaging accreditation programs, and MIPPA regulations further raise the significance of noncompliance. In addition, the Joint Commission recently announced New and Revised Diagnostic Imaging Standards for accredited health-care organizations which include aspects of MR Safety. The clinical medical physicist must be aware of all of these requirements, which will be covered in this presentation. In addition to regulations and requirements, the clinical medical physicist must be aware of practical aspects of MR safety. These include issues of direct patient care and employee safety. How does one set up and maintain a safety program? How can proper site planning lead to improved MR safety? How can ferromagnetic detectors be used to enhance the screening process? And what can be done when faced with a new implanted medical device for which the patient has no card? This presentation will also review practical patient care and employee safety aspects of MR safety.

Vanderbilt Medical Center, Nashville, TN
The planned publication date of the revised ACR MRI Quality Control Manual is the first or second quarter of 2014. The manual will be made available in electronic form on the ACR website. The website will include a link to frequently asked questions (FAQs), as well as planned annual updates to the manual. The required performance parameters identified in the 2004 version of the manual have for the most part not changed. An exception is that the previously required test for RF "cross-talk" has been removed and is now listed as optional. As part of the revised annual performance evaluation, the qualified medical physicist/MR scientist must: (1) repeat and verify the weekly technologist's QC measurements, (2) perform the scans required for accreditation submission and evaluate those measurements with respect to the criteria specified in the most recent version of ACR Phantom Test Guidance Document, and (3) assess the site's MRI safety program as recommended by the "ACR Guidance Document for Safe MR Practices: 2013". (1) The safety assessment should include a review of written policies, signage and safety training. The revised manual also includes the description and suggested use of the ACR "Small Phantom" for extremity or other special-purpose MRI systems that may not be able to accommodate the original large phantom. The revised manual includes alternate test procedures for both SNR and magnetic field homogeneity as described in the National Electrical Manufacturers Association (NEMA) publications and in AAPM Report 100. The alternate methods include both a single-image method and a two-image method for SNR assessment in addition to the original method recommended in the 2004 ACR manual. Alternate test methods for magnetic field homogeneity include the "phase-map" method and the "bandwidth-difference" method (Chen HH, et al Medical Physics 2006; 33:4299-4306). The bandwidth-difference method can be used in systems that do not provide access to either phase images or spectroscopy. Not included in the revised manual is a specific method for testing multi-element array coils or for testing parallel imaging with acceleration. The current manual recommendation is that the maximum SNR be measured for each individual coil element in a manner similar to surface coil SNR assessment. It is anticipated that when the most appropriate method for testing multi-element arrays has been identified and approved, the method will be incorporated into the manual by means of the annual update. All discussed revisions should be considered to be preliminary until final approval has been granted by the American College of Radiology. Identifying and analyzing safety-related events is a proven way to enhance the quality and safety of care. Data demonstrate that patient outcomes are improved when health-care providers actively engage in incident reporting. This session will review existing data and discuss how incident learning systems are currently used in radiation oncology. The essential features of incidents and near-misses will be presented, along with the criteria for reportable events under the various applicable regulations. The use of incident learning system at the departmental level will be discussed, along with recommendations for structuring and operating such systems. Though incident learning is coming into wider use within clinics, there is still a major unmet need to collect and share such information between clinics. This session will highlight one new system designed to enable this: the national Radiation Oncology Incident Learning System (RO-ILS). This system, sponsored by ASTRO and AAPM, provides a means for sharing safety improvement information with the legal protections afforded by its status as a Patient Safety Organization. Early experiences with this system will be shared, along with experiences from the SAFRON system, an internationally used open-incident reporting system.  Clinical studies of digital mammography versus screen-film mammography showed limited benefits in performance for digital over screen-film leading many to conclude that the true benefit of digital mammography would be in the advanced applications made possible by that technology. Now two of those applications, digital breast tomosynthesis (DBT) and contrastenhanced digital mammography (CEDM), have advanced to the stage of clinical use. Both technologies show clear performance advantages over standard mammography, but both have their limitations in terms of cost and, in the case of CEDM, the need to inject IV contrast. This talk will review the both DBT and CEDM, including the technology, clinical evidence, current clinical status, and recent technological developments.

What Medical Physicists Need to Know about Breast Imaging with Nuclear Medicine
Technology -Carrie Hruska, PhD.
The use of dedicated nuclear medicine technologies for breast imaging, such as molecular breast imaging (MBI), breast specific gamma imaging (BSGI), positron emission mammography (PEM), and dedicated breast PET, is growing and may be coming to your site. Will you be ready? Although these technologies have been under study for over a decade, concerns about radiation dose and unclear clinical indications for their use have limited widespread acceptance. Today, improved detector technology and modified imaging protocols permit imaging at reduced radiation doses. A growing body of clinical data supports their use as a functional complement to mammography and a low-cost alternative to MRI in certain diagnostic and screening settings. Medical physicists are responsible for providing clinical service to patients undergoing diagnosis and treatment and are delegated the primary caretakers of safety. As the complexity of the technology in providing these services has increased, so have the risks to the patient, the healthcare workers, and the public. Medical physicists' unique knowledge and skills must expand on what they already know and do with the complexity of technology to minimize familiar and unexpected risks as much as possible. One way to broaden their safety knowledge and skills is to formalize their approach through use of failure mode and effects analysis (FMEA). This hands-on session will show that FMEA is simply a more systematic approach to what medical physicists currently do in identifying risks for a clinical service process. Participants will complete a process FMEA on a single process step of a 3D conformal radiotherapy (3D CRT) breast treatment case. Failure Modes and Effects Analysis (FMEA) is a quality management tool adopted from industry and introduced to radiation oncology a few years ago. Together with other QM measures-incident reporting and fault-tree analysis -FMEA helps to identify risky points in clinical processes and to devise error (or 'failure mode') mitigation measures. FMEA has been thoroughly described in several publications, including the Proceedings of the 2013 AAPM Summer School. Typically, a group of involved clinicians choose a process, list its steps (process tree), and then brainstorm as to what failure modes at each step can lead to risky situations. They then rank each failure mode (1-10, with 10 being the worst) as to its occurrence likelihood (O), potential severity (S), and likelihood of detection before reaching the patient (D). Its potential impact is summarized by the Risk Probability Number (RPN), the product of O, S, and D. FMEA is iterative, as mitigation strategies need to be reevaluated after implementation, and increased experience may bring new failure modes to light. FMEA is well-suited to both large and small-scale clinical processes. Small-scale processes, with a limited number of steps and a small number of participants, can be performed quite quickly. This lecture presents two examples of this sort. The first is an FMEA of monitor-unit calculations for simple, after-hours ('on-call') treatments. The FMEA was performed by one physicist and, through informal presentations to other physicists and periodic therapist and new resident in-services, has helped modify department policy over a several years. The second is a newly initiated FMEA of deep-inspiration breath-hold for treatment of the left breast, performed by the physicists and simulation therapists involved in the treatment. We expect this FMEA to help identify risky areas and guide development of mitigating measures for this process.
Learning Objectives: 1. To know the basic steps of an FMEA. 2. To know the definitions and relative scales for the FMEA parameters O, S, and D. 3. To understand the FMEA approach in relation to small-scale clinical processes.

BICOE Stereotactic Breast Biopsy and Ultrasound -William Geiser, MS, DABR
In October 2007, the American College of Radiology started a new program called the Breast Imaging Center of Excellence (BICOE). The BICOE designation is awarded to breast imaging centers that have earned accreditation in the ACR's voluntary breast-imaging accreditation programs, including breast ultrasound with ultrasound guided biopsy and stereotactic breast biopsy, as well as the mandatory mammography accreditation program. Significant changes have been made to the program requirements for breast ultrasound that will need to be implemented by June of 2014 in order obtain accreditation. Along with the prone stereotactic breast biopsy systems, several mammography systems have add-on stereotactic biopsy systems that will need to be accredited if the facility wishes to obtain the BICOE designation. This lecture is designed to give the medical physicist the information needed to perform the necessary quality control testing on stereotactic breast biopsy, tomosynthesis-guided biopsy, and breast ultrasound systems, to obtain accreditation for those modalities. With this information the medical physicist will be able to help the facilities that they work with obtain the designation of Breast Imaging Center of Excellence. MR imaging of the breast is an important adjunct to mammography and ultrasound for the detection of breast cancer and for breast biopsy guidance. Diagnostic breast MRI protocols typically include T2-weighted fat saturated images and 3D T1-weighted dynamic contrast enhanced (DCE) multiphase images using a Gadolinium-based contrast agent. The DCE images are used to determine the kinetic signature of enhancing tissues in order to differentiate between benign and malignant lesions. MR spectroscopy and diffusion weighted images (DWI) may also be acquired in order to provide additional diagnostic information. The diagnostic value of breast MRI scans can be improved by choosing acquisition parameters that optimize image quality parameters such as SNR, contrast, and spatial resolution. As with any MRI protocol, achieving the desired image quality must balance the need for acceptable scan times. The timing and temporal resolution of the DCE series are important considerations. Breast radiofrequency (RF) coils are phased array coils capable of simultaneous bilateral imaging. A comprehensive breast MRI quality control program is important to assess the performance of the MRI system, as well as the breast RF coils.
Learning Objectives: 1. Provide and overview of breast MR imaging and MR-guided biopsy procedures. 2. Describe breast MR image quality criteria and protocol optimization. 3. Discuss the components of a breast MRI quality control program.

Landauer Medical Physics, Charlotte, NC
Much has been made of the need for robust clinical processes in support of safety and quality management, and that is indeed a crucial element of practice in which the medical physicist typically plays a key role as the only expert in the organization with any formal engineering training. Equally critical is attention to safety in the design of medical devices and in the superdevices created when they are interconnected and interact. The role of the clinical medical physicist in promoting safety of device design is indirect, but the local implementation of any new or repurposed technology should always include a careful analysis of hazards that device design might present in a given milieu, and again it is the clinical medical physicist who plays a leadership role in performing the hazard analysis and mitigation. This presentation will focus on neither of those essential roles of the medical physicist, which get good attention elsewhere, but rather goes further into the uncomfortable territory of professional responsibility. The very heterogeneity of backgrounds and training that many tout as the long-standing strength of legacy pathways into medical physics have also tended to foster a wide diversity in the ways that both medical physicists and others view the standing, role, and responsibilities of the clinical medical physicist. The technology for which we take responsibility is complex and inherently life-threatening. It is incumbent on medical physicists to establish themselves locally as the professionals who manage reliability, to take that responsibility seriously in our training and our practice, and to always be prepared to do what must be done to protect our patients from harm. We will survey some case studies of medical radiation accidents in which patients have been harmed or killed, with a particular emphasis on the ways in which clinical medical physicists have performed exceptionally (on either side of the bell curve). Some discussion will be offered as to the specific ways in which medical physicists should think about their role and responsibilities in the provision of highly reliable care.
Learning Objectives: 1. To better understand that the medical use of radiation is inherently dangerous. 2. To understand the role medical physicists have played in some high-profile radiation accidents. 3. To review the professional role and responsibilities of the clinical medical physicist in the safety of clinical practice.

Varian Medical Systems, Las Vegas, NV
Sophisticated techniques and technologies have now become the standard of care in radiation oncology. Complexity has increased the demands on radiotherapy professionals and equipment manufacturers for assuring safe operation. The keys to radiotherapy safety are no longer found only in device reliability, training, traditional QA, and vigilance. A broader, system-wide view must be adopted, where the "system" includes the entire constellation of devices, processes, and persons. Risk analysis must not only look at the interactions among the medical devices and their operators, but also at the effects of workflows, policies, regulations, environmental disturbances, and even culture. Preventing accidents is not as much an error-prevention problem as it is a risk control problem -controlling the risk of harm when an error inevitably occurs. We present a system-theoretic approach to risk assessment and safety design in radiotherapy, and use actual radiotherapy incidents to illustrate the concepts.
Learning Objectives: 1. Understand how system safety concepts apply to radiotherapy. 2. Learn the basic concepts of system-theoretic hazard analysis. 3. Appreciate how system safety concepts manifest in actual radiotherapy incidents. Recently, the American Association of Physicists in Medicine (AAPM) established a Medical Physics Practice Guidelines (MPPG) initiative to provide a clear and concise description of the minimum level of medical physics support that the AAPM would consider to be prudent in all clinical practice settings. As accreditation of clinical practices becomes more common, MPPGs will be crucial to ensuring a consistent benchmark for accreditation programs. MPPG reports will be freely available to the general public. Accrediting organizations, regulatory agencies, and legislators will be encouraged to reference these MPPGs when defining their respective requirements. Support includes, but is not limited to, staffing, equipment, machine access, and training. This session will describe the purpose and scope of MPPGs, the procedure for the development of a MPPG, and reports from TG-

Safety 3: Radiation Oncology Safety Stakeholders
B Fraass, 1 * J Schewe, 2 * C Negrut 3 * Cedars-Sinai Medical Center, 1 Los Angeles, CA, Philips, 2 Fitchburg, WI, Accuray, 3 Sunnyvale, CA In recent years there has been an increased interest in patient safety in Radiation Oncology, in part due to highly-publicized errors, such as those described in the New York Times. Clinical practitioners, professional organizations, manufacturers, and regulatory agencies have each responded to safety concerns in their own way, generating white papers, task group reports, new product safety features, regulatory changes, and an increased emphasis on training and credentialing. There has also been an increased interest in the use of techniques related to Risk Management, Human Factors, and Usability Engineering, both in industry and in the clinic. In particular, the TG-100 Report recommends the use of risk management tools to identify and mitigate safety issues in clinical practice. In addition to each group working independently, there has also been an increased interest in stakeholders from all areas working together in a coordinated way. The Radiation Oncology Safety Stakeholders Initiative (ROSSI) was created in 2010 by members of AAPM, ASTRO, and the RT Industry, with a mission "to recommend and facilitate safety improvements in radiotherapy through a common, independent and impartial vision broadly based on diversity of experience and knowledge among radiation oncology professionals." The first speaker in this session will provide a summary of the history, goals, structure, progress to date, and future directions of the ROSSI collaboration. The second speaker will describe the role of Safety Risk Management in the development and support of medical devices, including a discussion of the similarities and differences in its use in industrial and clinical settings. The final speaker will give an overview of Usability and Human Factors issues in medical software, along with a review of recommendations from the ROSSI working groups on Usability and Error Messages. Digital mammography has become the technology of choice for breast imaging with many FDA-approved systems already available and more on the way. Currently the FDA requires facilities to use quality control manuals published by the FFDM unit manufacturer. There are several accrediting bodies that run programs approved by the FDA. This lecture will provide updates on the FDA activities, ACR requirements, the upcoming ACR DM QC Manual for digital mammography. Approval and accreditation processes for digital breast tomosynthesis will also be introduced.
Learning Objectives: 1. Understand the requirements for accrediting FFDM systems. 2. Understand the requirements for certifying tomosynthesis systems with the FDA. 3. Be able to navigate the ACR and FDA websites to find required information and documents for certification and accreditation.

Advances in Full Field Digital Mammography -Mark Seddon, MS DABR
In 2011 the FDA switched form a pre-market approval (PMA) process to approve full-field digital mammography (FFDM) systems to their 510k-approval process. Since that time 19 new systems or variations of existing systems have been approved full-field digital mammography. These systems include computed radiography systems, full-field detector systems with new and existing detector technologies, and a photon counting system. At the time of the switch there were five vendors with approved systems; there are now 13 vendors in the FFDM market. Tomosynthesis and 2D synthesized images for interpretation have also been approved for screening mammography. This lecture will give the medical physicist information on the systems approved since 2011. Included will be information on detector technology, some of the differences in QC for the different vendors, and some of the new technologies that are being used to lower dose for patient imaging.

MONDAY, MARCH 17
Therapy Symposium -SAM Salon AB It has been twenty years since the AAPM published TG-34 on cardiac pacemakers of older technology, which has been the standard document for clinical use, even today, for managing patients with pacemakers (ICPs). Management of radiotherapy patients with modern technology cardiac implantable electronic devices (CIEDs) has been widely published in literature without the provision of a new comprehensive and concise set of recommendations. This need is clearly evidenced by the numerous postings on the medical physics list server groups inquiring about advice on dealing with these devices during patient imaging and radiation treatments. As treatment delivery technologies (IMRT, SBRT, dose escalations, proton beams, etc.) and CIED technology advance, the need to address the management of patients with such devices receiving radiation treatment becomes increasingly important. As such, this session will provide updated guidance for caring for radiotherapy patients with CIEDs. Two presentations will be delivered during this session. The first will focus on the work of AAPM TG-203 and provide a summary of the recommendations to the clinical user for management of patients with CIEDs when receiving RT. The second will focus on an institutional experience of managing patients with CIEDs.

Management of Radiotherapy Patients with Implanted Cardiac Devices
Learning Objectives: 1. Review the purpose and function of CIEDs. 2. Provide a review on sources of potential malfunctions of modern CIEDs, including malfunction mechanisms from high-LET radiation and transient effects attributed to medical imaging for radiotherapy. 3. Review the management of radiotherapy patients with cardiac devices. 4. Utilize recently available data and computation methods of out-of-field/peripheral dose by scattered photons and secondary neutrons estimate cumulative doses to CIEDs during treatment. Risk of failure associated with these doses will be discussed. 5. Provide comprehensive recommendations for management of radiotherapy patients with implanted cardiac devices from initial patient consultation to treatment delivery.

Dimitris Mihailidis (New Comprehensive and Practical Guidelines for Managing Radiotherapy
Patients with Cardiac Devices -TG203) Joann Prisciandaro (An Institutional Experience Managing the Care of Patients with CIEDs) The Nuclear Regulatory Commission provides several acceptable models for release of radioactive patients from radiation safety restrictions. The more computationally rigorous models can be used instead of traditional "rule of thumb" models to significantly reduce inconvenience to the patient and procedure cost. With hospital resources becoming scarcer and scrutiny toward radiation safety practices higher than ever, understanding and exploiting NUREG-1556 radioactive patient release models can provide benefit to all stakeholders. Medical physicists are consulted for leadership in many issues associated with patient dose. This includes measurement, interpretation and, more recently, tracking of patient dose. The integration of the collected data with patients' medical records continues to evolve, with the medical physicist playing a central role in the success of these efforts. Commonly used metrics and their applicability for commonly used imaging techniques are discussed. The recording and disposition of these metrics continues to evolve. The recognized need to track patient dose has led both equipment vendors and independent software developers to introduce systems capable of recording and providing statistical analysis of patient doses delivered during imaging studies. A review of some commonly available patient dose-tracking software systems is provided. Requirements and procedures for the review of, and incorporation of, patient dose into patient records is discussed with illustrative examples. This session highlights two critical and timely issues in radiation safety: release of radioactive patients from medical facilities and lifestyle restrictions, and patient dose tracking in X-ray imaging. Fundamental physics and safety concepts are discussed and illustrated in clinical examples, along with more subtle, but important, considerations for the practicing medical physicist.

Release of Radioactive Patients / Patient Dose Monitoring Software
Learning Objectives: 1. Review risk-based goals of appropriately timed release of radioactive patients from medical facilities and lifestyle restrictions. 2. Understand the reasonable patient release models provided by NRC guidance and their differences. 3. Introduce the various patient-specific lifestyle considerations that can be used as a basis for accelerated release. 4. Review clinical case(s) demonstrating the impact of utilizing reasonable assumptions for accelerating radioactive patient release. 5. Understand regulatory requirements for recording and reporting patient dose associated with imaging studies. 6. Understand the applications and limitations of the various metrics used to quantify patient dose. 7. Develop an appreciation for the capabilities and limitations of commercially available patient dose tracking software packages. 8. Identify techniques and the steps required to include patient dose data in patients' medical records.

Methods
A Varian TrueBeam STx with an aS-1000 digital imaging panel was used to acquire RapidArc QA images for 17 patient plans totaling 27 arcs; each QA was performed at 6, 8, 10, and 15 MV. The Varian Portal Dose Image Prediction algorithm was used to create the comparison image for the EPID acquisition. The 2D correction map consists of a correction factor for each pixel, created by dividing the measured flood field readings by the predicted flood. The gamma passing rates of uncorrected EPID QAs were compared to those of 2D-corrected QAs at 1%/1 mm, 2%/2 mm, and 3%/3 mm criteria. The two-tailed Student's t-test was employed to analyze the statistical significance between the uncorrected and 2D-corrected measurements at the 95% confidence level.

Results
The results showed a statistically significant improvement (p < 0.05) under all criteria and energies when using the 2D correction matrix. The improvement ranges from 0.4% (15 MV) to 4.1% (8 MV) at 3%/3mm. When we focused exclusively on large field sizes (equivalent square ≥ 15 cm), the improvement became more pronounced (1.3% (15 MV) to 6.7% (8 MV) at 3%/3 mm). In general, 8 and 10 MV showed better improvement than 6 and 15 MV.

Conclusion
A 2D correction matrix can substantially improve gamma passing rates for the RapidArc QAs. For 8 and 10 MV fields, the differences were more pronounced. The current Varian EPID panel calibration is insufficient; a 2D correction matrix would be recommended, especially when used for large fields. The jaw field size might be a superior predictor of the utility of a 2D correction.

Methods
Two separate VMAT treatment plans using a 6 MV flattening filter-free beam were delivered three times each to the cervical spine region of a Rando anthropomorphic phantom. Dosimetric measurements were made using GAFCHROMIC EBT3 film placed in a sagittal orientation at the midplane of the phantom and analyzed with FilmQA Pro software. Two separate PTVs were used, and the prescription dose was 24 Gy delivered in a single fraction with a maximum dose to the spinal cord of 10 Gy. The two PTVs were different, in that one partially encompassed the vertebral bodies and spinal cord (PTV 1) and the other completely encompassed them (PTV 2). Each plan was calculated using the Eclipse AAA and Acuros algorithms. Gamma analysis with a passing criterion of 3%/3 mm was used to assess the accuracy of plan delivery.

Conclusion
Treatment plans were delivered very accurately to the homogeneous phantom for either PTV; however, the lower passing rates associated with PTV 2 may be indicative of a problem with AAA in handling large heterogeneities in some plans. Improved agreement between calculation and measurement was seen with Acuros. Use of this algorithm, therefore, may be beneficial for spine SBRT and other highly heterogeneous targets, such as the nasopharynx.

MO-B-Salon AB-04
Are Output Measurements Always Necessary after CT Tube Replacement?

UT MD Anderson Cancer Center, Houston, TX
Purpose TX regulations and the ACR require that CT radiation output be measured within 30 days of major service. The most common major service is tube replacement. We hypothesized that historical QC data could be used instead to determine if output measurements are necessary, reducing the need for costly output measurements.

Methods
We reviewed 66 records of OEM tube replacements to determine with what frequency output falls outside specifications. We also conducted an experiment to verify that clinically significant output changes could be identified by comparing image noise in historical QC data with the same data after tube replacement. We used 30 days of historical QC data to establish a baseline noise level and 95% confidence interval (CI) for individual noise measurements. To simulate output changes, we acquired phantom images with our QC protocol while manually changing output (mA). We acquired ten images using the baseline output and ten images at each different "output". We evaluated individual images and subsets of images at each "output" to determine if the system was within the manufacturer's specifications.

Results
None of the 66 tube replacements resulted in an output change that exceeded specifications. Analysis of 30 days of historic QC data for our experimental system indicated a mean noise of 5.4 HU with 95% CI of 5.1-.5.7 HU. When using the mean noise of ten images acquired at each of the varying outputs, we were able to identify, with 100% sensitivity, images acquired at outputs outside manufacturer's specifications.

Conclusion
The results of our review of historical OEM tube replacement data indicated the likelihood of output falling outside manufacturer's specifications is low. Considering this, it is likely that by using QC data from programs required by regulation and the ACR, physicists can reliably verify radiation output stability remotely instead of making physical measurements.

Purpose
To assess the target localization accuracy estimated from radiopaque markers in dynamic tumor tracking irradiation (DTT).

Methods
This study included 15 patients who underwent four fractionated DTT for lung cancer. They had four or five radiopaque markers around a lung tumor. Before beam delivery, the orthogonal X-ray fluoroscopic monitoring was done for 20-40 sec. First, 3D positions of the markers were detected from the X-ray fluoroscopic images, and one marker was then assumed as a target. Next, the centroid of adjacent triple markers (PC), and the nearest (Pnear) and farthest (Pfar) marker positions from the target were determined from the remaining markers. Then, the distance between the target and each P at end-exhalation on the initial day of the treatment was defined as the reference distance. The target position in every fraction was estimated by adding the reference distance to PC, Pnear, and Pfar. The |mean|+2 SD of difference between the actual and estimated target position during monitoring (E) were calculated for PC, Pnear, and Pfar. These procedures were repeated for the other markers. The overall (M), systematic (Σ), and random (σ) errors (units; mm) were calculated with each method.

Results
The median distances between the target and PC, Pnear and Pfar were 37, 28, and 65 mm, respectively. The value of M in the centroid, nearest, and farthest method was (1.6, 2.7, 2.5),

Purpose
To describe an automated dosimetric quality assurance (QA) procedure for the Pinnacle 3 radiotherapy treatment planning system (TPS) for use in commissioning validation and annual TPS quality assurance.

Methods
A Pinnacle QA script was created which functions in the clinical treatment planning mode, as opposed to the commissioning mode commonly used for data comparison. The script iterates over the different treatment machines, modalities, energies, treatment devices, jaw, and MLC defined field sizes, and SSDs which correspond to annual water phantom measurements and/or prior commissioning results. Sequentially, the script created the beams, computed dose, exported the computed dose profiles, and compared them to measured dose data, which is normalized to report dose/MU. Automated analysis included graphical profiles and dose differences, as well as distance-to-agreement values, uniformities, penumbrae, depth-dose metrices, and other associated dosimetric metrices. A single verification report for physicist review and evaluation was generated. The script was run for dose matrix resolutions corresponding to those used for clinical planning (2-4 mm). An additional automated suite of geometric tests and typical patient plans is run in conjunction with these dosimetric tests to complete the TPS QA.

Results
The automated dosimetric QA procedure enabled rapid one-click comparison of measured dose and planned dose. The verification report provided physicists a concise and organized summary of the planned dose accuracy. Results were generally within TG-53/ and ESTRO Booklet #7 criteria (± 2%, ± 2 mm); however, dose deviations at depths ≤ Dmax varied and exceeded 5% for some dose-voxel resolutions and absolute voxel placements.

Conclusion
An automated dosimetric QA procedure for comparison of measured and planned dose was developed and implemented for the clinical acceptance of the Pinnacle 3 treatment planning system. This proposed procedure will be a valuable tool for routine clinical dosimetric TPS QA required during TPS upgrades and annual QA.

Purpose
Recently individual IMRT QA have been more and more performed with GAFCHROMIC EBT series films processed in Red-Green-Blue channel. However, the efficiency of this method is relatively low, as for each new box of film a calibration curve must be established. In this study, the authors proposed a novel method to process the GAFCHROMIC EBT series: to use the 16-bit gray-scale channel to process the film, which greatly increases the efficiency and accuracy of the QA procedure.

Methods
The authors firstly calibrated the GAFCHROMIC EBT2 film using gray-scale channel in three dose ranges, and established a Pixel value-to-dose calibration curve. This calibration curve was implemented into an in-house film analyzing software. This method of film processing was then used to perform the QA of 743 IMRT cases across two radiation therapy centers, and the QA results were compared with ionization chamber measurements.

Results
The authors find that within a dose range of 0 to 600 cGy, the GAFCHROMIC EBT2 film presents a perfect linear PV-to-dose calibration curve when processed in the gray-scale channel. This fact greatly improves the accuracy and efficiency of calibrating GAFCHROMIC EBT film, as with a known linear relationship, only two data points are needed to establish the calibration curve; the fitting error is also significantly reduced. The whole procedure can be further simplified if the film is used for relative measurements only. Among the 743 clinical cases tested, 740 cases passed the 3%3 mm gamma-function assessment and the results agreed well with ion chamber measurements. The failed three were found to originate from human mistakes.

Conclusion
The authors confirm that the novel method is effective and efficient. Clinical testing has shown consistent results, proving that this method can be used to replace the conventional R-G-B method to analyze GAFCHROMIC EBT2 films in IMRT QA.

Methods
Data from 27 previously treated patients were analyzed using Oncentra treatment planning. Treatment plans were based on CT scans using a GE LightSpeed with 1.25 mm slice thicknesses. For each patient, two new treatment plans were generated, each with a catheter rotation and otherwise identical treatment parameters. The dwell-time optimizations from the original plan were used to simulate the catheter rotations. The dose-volume histogram was analyzed for each plan and compared with the sample population to determine the mean distributions and standard deviation.

Results
Coverage of the PTV was maintained for any rotation of the MLB plan, with a mean change of 2.2%. The mean changes to the skin and chest wall were 9.5% and 16.6%, respectively. While the mean dose changes to these critical organs do not appear extreme, instances of overdosing of as much as 58.3% and 79.9% were observed. The mean change to the V150 and V200 were 1.13 and 0.81 cubic centimeters, respectively.

Conclusion
During simulation, marker wires are placed in each channel by the physicist or a member of the Radiation Oncology team. There is a potential for the marker wires to be placed in the incorrect channel, which will cause the treatment to be delivered as if the balloon is rotated. The balloon may also rotate due to movement in the patient. These factors can both lead to the results above. For patients with minimum OAR separation distances of less than 9 mm or treatment plans with several dwell locations turned off, we recommend a CT scan before the first fraction of MammoSite treatment as a check against an erroneous catheter rotation or misidentification.

Purpose
To design a set of site-specific treatment tolerance tables with a customized indexing system that will insure accurate patient setup with minimal workflow interruption.

Methods
A retrospective analysis was performed on a total of 74 patients and 1428 treatments, separating them into nine distinct categories based on site of treatment and method of immobilization. Couch parameter tolerance tables were designed to encompass 95% of treatments and were generated by calculating the standard deviation of couch vertical, longitudinal, and latitudinal values using the first day of treatment as a baseline. A custom device was then constructed to be used for indexing patients who lacked a means of indexing, and the system was implemented on a linear accelerator at our cancer center in order to determine its feasibility.

Results
During this trial period, we collected data from 188 fractions from 13 patients and five sites, and analyzed the number of treatments that would have been out of tolerance and whether the tolerances or setup techniques should be adjusted. Of those 188 fractions, 52 (28%) would have required physics intervention if the original baseline was kept for further reference and 29 (15%) if the baseline was changed after every tolerance violation. The use of the indexing device allowed for pelvis sites to be set up with results similar to that of wing board/immobilized patients from the initial study (e.g., 2.02 cm vs. 1.64 cm average deviation in longitude). The results also indicate an increase in tolerance size for some sites may be necessary if issues in setup cannot be addressed.

Conclusion
Further data collection and refinements to patient indexing technique are required before the tolerance tables are implemented. Our initial results show promise that a system can be developed that will enhance patient safety without hindering clinical efficiency.

Purpose
This study was conducted to validate the Monte Carlo algorithm for electron therapy in the Eclipse treatment planning system. Irradiation with electrons offers the advantages of dose uniformity in the target volume and in minimizing the dose to deeper healthy tissue. Using the Monte Carlo algorithm will improve dose accuracy in regions with heterogeneities.

Methods
Dose distributions from film measurements were compared to dose distributions from Electron Monte Carlo, and Pencil Beam algorithms in Eclipse. These measurements were obtained for 6 MeV, 9 MeV, and 12 MeV electrons. All phantoms studied were imported into Eclipse by CT scan. A 1 cm thick solid water template with one square and two circular holes for bonelike and lung-like plugs was used. Each configuration had either all bone or all lung plugs. Film measurements were taken at two depths for each energy. The depths used were the depth of maximum dose (dmax), and a depth greater than dmax. Ionization chamber measurements were also obtained at different locations and were used for comparison and to verify the film measurements.

Results
The accuracy of Electron Monte Carlo was compared to that of Pencil Beam. The dose from Monte Carlo agreed better than that from Pencil Beam for all configurations and depths. The pass rate for Monte Carlo was in the 80%-99% range, where the pass rate for Pencil Beam was as low as 10.76%. Ionization chamber measurements verified that the dose given from the film was accurate.

Conclusion
The dose distribution from Monte Carlo agreed much better with the measured dose from the film when compared to the Pencil Beam algorithm. The pass rates for Monte Carlo were significantly higher than those from Pencil Beam. Monte Carlo should be used over Pencil Beam for regions with heterogeneities. This session will address professional aspects of the certification process and interviewing for clinical medical physics positions. It will include the latest updates relevant to medical physics certification through the American Board of Radiology processes, including initial certification, maintenance of certification, and the examination process. The second portion of the session provides a relaxed and fun session for those seeking to improve their interviewing skills. You got your foot in the door, they liked your resume, and thought you looked interesting enough to bring out to meet face to face. How do you showcase your skills, while simultaneously showing them how well you would mesh with their current team? How do you respond to these newly popular questions that seem more interested in your feelings than in your technical skills? How do you pick up on the details that might clue you in that this potential employer isn't right for you? Our session will give you concrete advice with examples to give you the tools you need to be successful in your next interview.

Safety Culture Leadership: What Can We Learn from High Reliability Organizations?
In 2011, the U.S. Nuclear Regulatory Commission enacted its Safety Culture Policy Statement requiring licensees to establish and maintain a "positive safety culture." Since that time, the NRC and state radiation regulatory agencies have begun to clarify how they will implement this policy in rule-making, inspection, and so forth. There is a great deal of room for interpretation about what it means to have a safety culture and how to achieve it. Medical physicists, in their common roles as clinical physicists and/or Radiation Safety Officers, are responsible for providing leadership in these programs, including the creation of policies and procedures and monitoring compliance within medical organizations. To provide the clinical physicist and Radiation Safety Officer with specific and actionable ways to create and maintain safety culture, this talk will examine the characteristics of High Reliability Organizations (HRO), such as naval aviation and nuclear power, that are inherently very dangerous but have established extraordinary track records of safety. These characteristics result from practices that are adopted by the leaders and taught and reinforced to all members of the organization. The behaviors that make an organization an HRO inherently create and sustain strong positive safety cultures.

"How I Learned to Love Databases and Stop Abusing Excel"
Spreadsheets are a common approach to storing lists and data that would be more useful and functional in a database. The problem is that it is very easy to create a blank spreadsheet to enter and manipulate basic data. Many spreadsheets become large and unwieldy and contain huge amounts of mission-critical information before their users begin to encounter limits on what the spreadsheet format can handle. Relational databases, on the other hand, are powerful tools, but they usually require specialized knowledge to create and maintain. This overhead seems daunting and unnecessary for a "lightweight" task, and so spreadsheets proliferate.
This lecture will explore the concepts of database design and implementation, and review how to recognize an application where a database is a superior choice to spreadsheets for data management. Participants should gain the ability to define the requirements of a database development project, discuss requirements and features with database developers and software vendors, and, if motivated, to begin learning the functional aspects and syntax of a specific database environment.

A Olch
Children's Hospital of LA, Los Angeles, CA The dosimetric impact from devices external to the patient is a complex combination of increased skin dose, reduced tumor dose, and altered dose distribution. Although small monitor unit or dose corrections are routinely made for blocking trays, ion chamber correction factors, or tissue inhomogeneities, the dose perturbation of the treatment couch top or immobilization devices are often overlooked. These devices also increase surface dose, an effect which is also often ignored or underestimated. These concerns have grown recently due to the increased use of monolithic carbon fiber couch tops, which are optimal for imaging for patient position verification but cause attenuation and increased surface dose compared to the "tennis racket" style couch top they often replace. Also, arc delivery techniques have replaced stationary gantry techniques, which cause a greater fraction of the dose to be delivered from posterior angles. A host of immobilization devices are available and used to increase patient positioning reproducibility, and these also have attenuation and skin dose implications, which are often ignored. This report of Task Group 176 serves to present a survey of published data that illustrates the magnitude of the dosimetric effects of a wide range of devices external to the patient. The report also provides methods for modeling couch tops in treatment planning systems so the physicist can accurately compute the dosimetric effects for indexed patient treatments. Both photon and proton beams are considered. A discussion on avoidance of high-density structures during beam planning is also provided. An important aspect of this report are the recommendations we make to clinical physicists, treatment planning system vendors, and device vendors on how to make measurements of skin dose and attenuation, how to report these values and, for the vendors, an appeal is made to work together to provide accurate couch top models in planning systems.
Learning Objectives: 1. What are the dosimetric effects of couch tops? 2. What are the dosimetric effects of immobilization devices? 3. How can one model couch tops in the treatment planning system? 4. How can one measure attenuation and surface dose changes due to external devices?

R Siochi
University Of Iowa, Iowa City, IA The transfer of data along the chain from imaging to treatment in radiotherapy has been a source of errors. TG201 has written a rapid communication to deal with this issue, and is also in the process of writing a full report that details the typical environments and data communication models in radiotherapy, along with recommendations on the QA tests, philosophies, and methodologies. Single database systems from single vendors, as well as systems comprised of a network of mixed vendors, will be explored in terms of the exchange of data among various subsystems. Methods for analyzing one's data transfers (e.g. the data transfer matrix), the associated risks (e.g. prospective fault tree analysis), and the required tests, will be presented. Along with these tests, the design of more robust clinical workflows involving data transfer procedures will be explained.
Learning Objectives: 1. Understand the various data communication models and identify the one used in your clinic. 2. Learn strategies for analyzing data transfer risks. 3. Understand the principles of robust clinical workflow design as it relates to data transfer procedures.

MO-D-Salon CD-01
Refresher and What's New in PET / Gamma Camera Cardiac Imaging O Mawlawi, 1 * R Quaife 2 * MD Anderson Cancer Ctr., 1 Houston, TX, University of Colorado, 2 Aurora, CO This talk will cover basic PET image acquisition and formation. Description of data formats, corrections, and quality control will be provided. The talk will also cover recent developments in PET imaging such as TOF, resolution recovery, continuous Bed motion, reconstruction, and PET/MR. Imaging of cardiovascular disease is rapidly progressing to a disease-specific quantitative diagnostic methodology. This movement is highly dependent upon physics-based improvements in reconstruction algorithms, and acquisition hardware and software, which are all focused on the goals of greater accuracy and reduced radiation dose for our patients. This push for quantitative cardiac assessment includes development of disease-specific radiotracers. These advances in tracers and technology have stimulated development of merged imaging modalities aimed at rapid imaging of both structure and function of the heart. This session includes a review of fundamental concepts in emission imaging. Recent developments in both applied physics and the clinical realm are also featured.

Houston, TX
A number of guidance documents are aimed at supporting quality care in radiation therapy. However, much can be learned by evaluating and comparing practice patterns, determining areas of deficiencies, and providing support to programs. In the United Kingdom, an audit program was established as part of a national effort to standardize and improve the quality of care. The program includes site visits by physicists from other centers where measurements are performed along with a review of the program. These visits have led to a variety of improvements nationally. In Ontario, the Cancer Care Ontario program has a similar goal of improving quality throughout the province. The collaborative quality assurance (CQA) program was established to assess the planning and delivery quality of both static-gantry IMRT and arc-based IMRT delivery (e.g., VMAT and TomoTherapy) through a standardized end-to-end test which includes planning exercise and a site visit. 14 centers have participated in the program in the first two years, with tests completed for both prostate and head and neck cancer. In addition to results comparing the planned to measured dose distributions, feedback is provided on the planning practice, phantom set up, plan delivery, beam model and machine performance. Extension of the CQA funding to 2017 enabled a program designed to assess change in planning and delivery performance through repeat visits. In North America, the quality of irradiation and beam commissioning is evaluated for radiotherapy centers participating in NIH-sponsored clinical trials. These remote dosimetry and phantom programs have supported assuring quality in trials with 1809 and 236 participants throughout North America and elsewhere in the world, respectively. These North American audits have not only improved the accuracy of dose delivery for clinical trial participants, but have also yielded secondary benefits to Radiation Oncology practice and patient safety.

Learning Objectives:
1. Learn about a mechanism to improve the quality of care through an audit program in the United Kingdom. Recent revisions to the American College of Radiology's ultrasound accreditation program requirements (http://www.acr.org/~/media/ACR/Documents/Accreditation/US/Requirements. pdf) may alter the way many ultrasound practices view quality control (QC) in ultrasound. Unlike the previous ultrasound QC recommendations, the new requirements consist of multiple components which define a comprehensive QC program. The main components of the QC program are acceptance testing, the annual survey, semiannual (or preferably quarterly) routine QC tests, and preventive maintenance. A comparison to ACR QC requirements in other modalities suggests that QC should be a team effort, with the QC program design and oversight, acceptance testing and annual survey being the responsibility of the medical physicist. The routine QC would be the responsibility of an imaging technologist, and preventive maintenance would be the responsibility of a service engineer. The best approach to meeting the new ACR ultrasound requirements is a team approach, with all of these professionals working in concert to create and sustain an effective QC program. The ACR strongly recommends that the QC program be supervised by a qualified medical physicist. As a result, we expect physicists to be asked to play a major role in the design and supervision of these QC programs. The new ACR accreditation program requirements provide no specifics regarding acceptance testing, except that that it should include the annual tests in order to provide baseline data. For the annual survey, seven tasks are specifically required: physical/mechanical inspection, uniformity/artifact survey, geometric accuracy, system sensitivity, scanner display performance, primary interpretation display performance, and evaluation of the QC program. Two additional annual tasks are optional: contrast resolution and spatial resolution. The routine QC tasks include: physical/ mechanical inspection, uniformity/artifact evaluation, scanner display performance, primary interpretation display performance, and geometric accuracy (the last is only for mechanically scanned transducers). The specifics of how to perform these tests and analyze the results are not provided, and are left in the hands of the person designing the QC program. The purpose of this session is to provide medical physicists with the tools they need to meet the new ACR requirements for ultrasound accreditation. The first part of this session will cover how to perform an annual survey of ultrasound equipment. The second part will address the physicist's role in implementing and supervising a continuous ultrasound QC program.
Learning Objectives: 1. Understand the new ACR requirements for ultrasound quality control and the roles of the medical physicist. 2. Learn the basics of how to perform an annual survey of an ultrasound system. 3. Understand the physicist's role in implementing and supervising the routine QC testing process.
Sandra Larson (ACR Requirements and the Annual Survey) Nicholas Hangiandreou (ACR Requirements for Routine Quality Control)