Sample content of kinesthetic educational training: Reducing scattered X‐ray exposures to interventional physician operators of fluoroscopy

Abstract Content used by Medical Physicists for fluoroscopy safety training to staff is deliverable via several formats, that is, online content or a live audience slide presentations. Here, we share one example of a kinesthetic (live, hands‐on simulation) educational program in use at our facility for some time (~10 years). In this example, the format and content specifically target methods of reducing physician operator exposures from scattered x rays. A kinesthetic format identifies and promotes the adoption of exposure‐reducing behaviors. Key kinesthetic elements of this type of training include: physician hands‐on measurements of radiation levels at locations specific to their standing positions (e.g., primary arterial access points) in the room using handheld exposure rate meters, measurement of exposure rate reduction to physicians provided by using personal protective equipment, that is, wearable aprons, hanging lead drapes, and pull‐down shields. Physician choice of procedure‐specific tableside selectable controls affecting exposure rate from optional fluoroscopy, Cine or digital subtraction angiography (DSA), along with comparative measured contribution to physician exposure is demonstrated. The inverse square exposure rate reduction to physicians when stepping back from the table during DSA is a key observation. Kinesthetic simulations in the rooms used by physicians have been found to provide the highest level of understanding giving rise to adoption of practices that are impactful for physicians. Specific training scripts are in place for physician sub‐specialization in interventional radiology, cardiology, neurosurgery, vascular surgery, and gastroenterology. This training is used for new physician staff while classroom presentations (whose content mimics in room training) are used with staff who have had previously had in room training.


| INTRODUCTION
Elevated physician operator exposure from x-ray scatter occurs primarily with specialties utilizing interventional C-arm devices. Interventional radiologists and other specialty users are consistently and historically among the highest occupationally exposed workers in a hospital system due to their extensive use of fluoroscopic imaging and in particular the incorporation of digital subtraction angiography (DSA) and Cine acquisitions. 1 Options exist in providing safety training education to physician staff, including an online educational self-guided module such as a slide presentation or live learning streamed over the internet and live audience slide presentation by a qualified medical physicist (QMP). 2 These options are widely used by hospitals as they can ensure completeness of staff as having received required education and providing documentation that this has occurred. Online options greatly facilitate scheduling of physician staff time. Less frequently used are live hands-on kinesthetic simulation sessions as its use has impediments for implementation including physician and imaging room availability.
Kinesthetic intelligence has been separately recognized among those individuals who effectively best learn by doing. 3 As early as 1983, published educational research has shown that various specialty training such as medical surgery is best learned by physical movement. It may be somewhat self-selecting that those physicians who are drawn to surgery as a career choice are natively gifted with kinesthetic intelligence. 4,5 A fluoroscopy educational format that uses a live in room simulation (kinesthetic education) to a targeted audience may be well suited for the interventional x-ray procedure physician. The added advantage of this approach is that hands-on training simulation can be specific to the specialist physician operators of interventional fluoroscopy devices including radiology, cardiology, neurosurgery, vascular surgery, and gastroenterology. This manuscript presents content used to create kinesthetic simulations at our facility with examples of the types of physical setup and teaching points found to be helpful. An overarching theme of our curricula has been to provide the specialty physician with basic educational content focused on topics controllable by their kinesthetic movements. For example, the physician directs the positioning of protective shielding during interventional procedures. The content is very basic in its focus; these sessions do not delve into the physics of the device settings or the comparative evaluation of the numerous device features which can lower scattered x rays. These items and additional fluoroscopy safety topics are available for use in separate more conventional education sessions.

1.A | Kinesthetic education
Educational science has long recognized that "viewed only" content provides about 10% retention while both audio and visual content may achieve 30%-50% retention. Kinesthetic movement and actions performed by the participants achieve nearly 90% retention. 6   actually selected for use for frequently performed procedures). As this is an interventional fluoroscopy focus training session, it is expected that procedures using cone beam CT and DSA, or Cine will be available and incorporated for class use. It is also important to note the presence of a power injector for contrast and its frequency of use with procedures. The QMP must be familiar with operating the device including modification of tableside settings, table and Carm movement controls, and location of tableside geometry display.
Another option is to enlist the aid of an x-ray technologist who is familiar with these device operations. The QMP must also be familiar with the movement of hanging drapes on the table and the range of movement and positioning of pull-down shields from their storage position to their best location for physician protection with any access points used with procedures in that room. This information is incorporated into the Script for class use.

2.A | Handheld educational devices
A handheld ionization survey meter is needed and an independent xray beam dosimetry system can be useful. A distance measurement PAVLICEK ET AL. | 197 tool is quite important. We have selected a yellow plastic cord for which three knots are created at 0.5, 1, and 2 m. This string is tied to a large metal washer to anchor the end of the string in the center of the x-ray beam. A stack of Poly(methyl)methacrylate (PMMA) is used along with a life like head, neck, trunk, and extremity phantom.
While a human like form phantom is not necessary, it has helped in quickly identifying the standing positions and measurement points for x-ray scatter.

2.B | Teaching script
A prepared script serves several functions. It ensures that the desired content is included in the exercise and that this content is discussed in the desired sequence. Each participant gets a copy of this script which they use to participate in the session. If in-room training is early in the morning before patients, a well-scripted program can ensure completion by the scheduled time. To emphasize T A B L E 1 A class handout Script is specific to the attendee's use of fluoroscopy, patient positioning and physician position with device access.
Script: Physician operator exposures from X-ray scatter fluoroscopy with interventional radiology

Teaching points
For: IR attending physicians, IR fellows and IR residents 1. Origin of scatter and C-arm geometry Distance of patient from tube, detector close to patient.
Setup: Patient phantom is supine with x-ray source under the table. Detector is 10 cm above the patient. • Where is the origin of scatter radiation to staff?
• What is scatter exposure rate at 0.5 m from point of scatter at table height?
• What is the most frequently used fluoroscopy dose rate curve?
2. Bad C-arm geometry Bad geometry can be avoided.
Setup: Patientsupine with 25 cm Detector AIR GAP and TABLE at 10 cm below IRP (25 cm below Isocenter) • What is exposure rate at 0.5 m from point of scatter at table height?
• What increase in scatter x rays to physician is seen with bad geometry?
3. Effect of patient size/steep angles Larger thicknesses increase scatter.
Setup: Patient is supine -22 cm FOV and good geometry ADD 5-8 cm PMMA.
• What is the exposure rate 0.5 m at waist? • What is the participants estimate of STAFF EXPOSURE from DSA at 1.0 m compared to 0.5 m above?
• What is the participants estimate of STAFF EXPOSURE from DSA at 2.0 m compared to 0.5 m above?
• What physicians or other staff must be tableside with patient with DSA?
• Who announces that DSA will be initiated?
6. Effectiveness of PPE Apron, hanging lead from table, and pull down shield are essential.
Setup: Large size patient supine, 10 cm air gap 22 cm FOV (good geometry) • What is staff exposure through lead apron tableside with fluoroscopy to body?
• What is staff exposure through hanging lead with fluoroscopy to point at bottom of lead apron?
• What is the staff exposure to head with and without pull-down shield? Use DSA • Do hanging lead drapes and pull-down shields locate to ALL positions used for arterial and venous access?
• Given the choice of standing tableside, which position (patients left or right) will result in less scatter to physician? • How much difference occurs in scatter rates between x-ray tube side and image receptor side? • Where is the origin of scatter?

Wrap-up
Summary of important choices and good practice for reducing physician exposures • Good geometry, choice of pulse rate, tap and pause, stand back with power-injected DSA.
• Availability of PPE for all arterial and venous access points is a must. Use of pull-down shield is hugely important. • Always use badge, placed outside of PPE at level of neck, outside of thyroid collar.
The legend organizes the content in the QMP desired presentation order of educational points. It allows for participants to interject their specific points of discussion in relation to observed levels of scattered x-rays. Bold in the Table is the title of the corresponding teaching objective.
the kinesthetic aspect of this education, the instructor engages each participant to handle all devices as much as possible. A participant that performs actions as the class is (not surprisingly) more engaged in the topic and memory of the teaching points are facilitated. Table 1 depicts a sample of scripted content that is handed out with Interventional Radiology physician in-room education sessions.
Here, the topic is reducing physician exposures from x-ray scatter  --------------X-ray Tube Focal Spot ------Detector X-ray Beam The class is joined together in visual inspection of a "dot" or marking on the tube housing which depicts the focus and the origin of x rays, the low absorbing table and pad, and the image receptor.
Where is the origin of x-ray scatter?
The origin of scatter is stated to be the area of the back of the supine patient struck by the x-ray beam. The example of a flashlight beam striking the instructors hand causing large amounts of scattered light has been used as a visual.

Good Geometry
The concept of isocenter and the need to angle the C-arm about a vessel is given, noting that the isocenter to focus is fixed while the image receptor allows movement. Having the vessel of interest at isocenter allows the image to remain in the image with Carm angulations.

3.A | Origin of scatter and C-arm geometry
The class starts with the instructor pointing to markings on the x-ray tube housing depicting the position of the x-ray tube focal spot as the point at which the x rays are produced. In turn, each participant confirms seeing the mark of the x-ray tube focus and collimation.
Collimation is simply depicted as forming the beam as it travels to the patient. All participants are asked to step closer to see these staff, these scattered x-radiations may or may not travel through and be attenuated by the patient before striking staff. This is also confirmed using the survey meter with the participants. Exposure to a physician's knees gives higher exposure rates of x-ray scatter than the waist or head as they stand tableside (measured values without PPE). A technologist standing at the foot end of the table is seen to not receive much exposure due to attenuation and distance as measured by a participant. The area of the beam landing on the patient is also a factor in the amount of scatter. This can be easily demonstrated by a participant using the handheld survey meter at the waist level as the collimation or FOV is changed.
Radiation that is not scattered (the primary beam) will pass through the patient, but this radiation is considerably absorbed with roughly only~10% passing through the patient to strike the image receptor. To emphasize the importance of knowing the origin of scatter, the instructor emphasizes to the class to remember the origin of scatter as it will be part of the test at the end of the session as indicated in the Script.
Good geometry is depicted with a phantom on a table and the table top at 15 cm below isocenter and the image receptor no more than 10 cm above the patient and preferably closer. As the vessels in mid-brain, neck, chest, abdomen and legs are nearly all mid-line, the majority of interventional imaging has these vessels at C-arm rotational isocenter so as to ensure the vessels remain in the center of the image receptor with any C-arm angulation. This table and receptor positioning is standard practice for initial patient positioning with x-ray technologists in preparation for physician use. The physician recognizes that good geometry with table and receptor positioning is a worthwhile learning objective; table height affects the amount of xray scatter and it also relates to "work height" by the operator. In this The tableside display of mGy per minute is only valid for the interventional reference point. Optionally, the SME can position an independent ionization sensor at this location to compare to air kerma at the interventional reference point.

3.B | Bad C-arm geometry
Bad geometry is depicted with lowering the  geometry. This difference is the amount of patient dose that is often controllable and often can be reduced without affecting the procedure. The learning objective with this section is to incorporate good geometry as standard practice. The table and image receptor are returned to good geometry for the next Script topic.  F I G . 1 4 . In this example, a 250% higher than an average sized patients scatter was observed. While uncontrollable, a large-sized patient could have device settings or choices that may mitigate the amount of scatter. What would be some options that would be helpful to lower the scattered x rays? slowly.The slower movement of the catheter permits the use a reduced pulse rate (even one that introduces some image jitter) which is capable of reducing the rate of scattered x rays to the patient by 50%. 8 If desired or used by the physician participants, an alternative arterial or venous access location (neck and/or arm) and use of left side access is additionally evaluated for differences in scattered x rays reaching these locations.

3.E | Effect of stepping back
The participants are directed to view the washer that is seen in the center of the image. The other end of the yellow string is extended and held outwards to 2 m by a participant. The first knot at a distance of 0.5 m is quite representative of the anterior waist of a performing physician to origin of scatter when using a femoral approach. With  This is quickly done using the handheld survey meter with participants holding the apron. The apron is shown to block scattered x rays (not primary beam) and a protection factor is estimated. Apron PPE are available in various thicknesses and the reduction in exposure rates from x-ray scatter to physician operators can achieve 90% or can be lower with lighter weight aprons. Differences in physician preferences can be identified if desired and their use in an interventional x-ray facility having Cine or DSA can be standardized. 9,10 Hanging tableside drapes are shown to reduce the exposure by more than 90% via measurement. It is an important pre-procedure

3.G | Quizlateral C-arm geometry
The C-arm sometimes is used in a lateral or near lateral projection and frequently the image receptor is found to be positioned on the meter is used to confirm the answer and the situational use of lateral projections and staff location are discussed. Surgeons, and Gastrologists. A phantom that better simulates arterial and venous accent points (or mouth access for ERCP procedures) is compelling to physicians as it correlates well with their experience and standing position relative to the patient and source of scatter. 11 In some instances during our education session, it was found that patient left side procedures had been initiated as a clinical service but left side hanging drapes and pull-down shields were not yet physically in place and available. Making changes to the ceiling mounted boom to support an additional pull-down shield is costly and generally cannot be quickly added to a fluoroscopy room. Although a post education survey was not performed, the physician staff asked for repeated hands-on classes as new staff members have joined including residents, surgical fellows, and physician assistants. For interventional fluoroscopic devices that employ DSA or Cine, the physician operator can benefit from a specialty-specific kinesthetic training experience as it provides for adoption of key behaviors into routine practice. These behaviors are gleaned during the kinesthetic session as measurements of radiation and the utility of shielding, its positioning, and device operable parameters are comparatively evaluated and the physician exhibits preference in its use.

| DISCUSSION
Conclusions are drawn with practice changes that can be replicated and incorporated into daily use. In our experience, a kinesthetic format is not needed on an annual basis for individuals who have already had kinesthetic education or for which routine practices have incorporated the applicable safe practices. 12,13 Class room presenta-

Power Injection
Step Back F I G . 2 4 . An example of stepping back with power-injected digital subtraction angiography (DSA) is given.

Quiz
• Are C-arm angulations for lateral projections used?
• Is it better to position oneself on the image receptor or x-ray tube side for lateral projected fluoroscopy?
• What is their relative scatter exposure rates? F I G . 2 5 . The "kinesthetic" quiz is posed as to where to stand (left or right side of patient) obtain lower scatter with lateral projections of the C-arm.

| CONCLUSION
A kinesthetic education format was developed and has been found to be impactful for improving operational safety of the physician staffarguably the best testimony a measure of education quality.
Physicians gained insights and recognition of the value of adopting controllable best practice behaviors. The key behaviors of table and receptor positioning, suggestions for dealing with the high exposure rates found with larger sized patients, understanding the dose rates associated with DSA relative to fluoroscopy and the value of stepping back if possible were demonstrated. While the session uses the term "controllable behaviors", a kinesthetic education format whose content is aligned for each physician specialty was anecdotally found to be highly effective as compared to generalized educational formats using online self-directed modules.

CONFLI CT OF INTEREST
William F. Sensakovic is founder of Telerad Physics Teaching, LLC.
All other authors declare that having no conflicts of interest.