A hands‐on introduction to medical physics and radiation therapy for middle school students

Abstract Lesson plans were developed to present concepts of medical physics and radiation therapy to a middle school audience. These workshop learning units relied on hands‐on participation and collaboration within student groups to acquaint students with computed tomography simulation and treatment planning processes. These lesson plans were delivered at two different educational outreach programs targeted at student groups that have traditionally been underrepresented in science, technology, engineering, and mathematics (STEM) fields. The lesson plans are scheduled to be delivered at a third program in the future. The activities were used to introduce occupations in medical physics and radiation therapy as possible career opportunities for students, and to generate enthusiasm for continuing STEM education. Lesson plans are available upon request for educators interested in exploring medical physics educational outreach activities in their communities.

these lesson plans were developed for a middle school learning audience.

| MATERIALS AND METHODS
Lesson plans were created for two programs in the Seattle metropolitan area: the Burke Museum of Natural History and Culture's "Girls in Science" Program, and the University of Washington-Bothell's "Inspire STEM" Festival. The Inspire STEM Festival is supported by locally based organizations including the Boeing Company, and the Girls in Science Program is supported in part by a grant from the National Science Foundation. Both of these programs are designed for students in grades 6-8, with attendance especially encouraged for members of student groups traditionally underrepresented in STEM, including girls, minorities, students from low-income families, and possible future first-generation college students. 10 The workshops used overlapping content and learning materials. These lesson plans were prepared as an introduction to medical physics and radiation therapy using activities that are straightforward to implement with inexpensive classroom materials (all required equipment was donated or readily available at local hardware and art supply stores). Learner-centered activities [11][12][13] were developed to promote student engagement in solving problems, to give students control over the learning process, and to avoid the traditional active teacher/passive student roles.
These lesson plans were designed to foster active learning environments, 14

2.A | Immobilization and localization activity
The first activity was designed to introduce students to practical considerations of computed tomography (CT) simulation. For this activity, each student group was provided with simple materials including a ruler, fabric tape measure, roll of painter's tape, four meters of fabric, pencils, and paper. Students were also supplied with samples of customized thermoplastic masks used for head and neck treatments. The thermoplastic masks were used as examples of immobilization and localization equipment used clinically, though students were instructed that the masks would not likely prove useful for this activity. Photographs of the activity's supplies are included in Students were asked to choose one student to act as a patient who would receive radiation therapy treatment for bony metastases to the right and left tibia. Together the groups brainstormed how to complete the entire activity. First, the "patients" were instructed to position themselves on a classroom table surface that would represent both the CT scanner table surface as well as the linear accelerator couch surface. Students were encouraged to use any tools available to them to delineate their group's patient's position.
They were reminded to be respectful of their patient and the host institution's facilities. After a specified amount of time, the patient was asked to leave the treatment position carefully, walk across the room, and then return to their group's table. The group then arranged their patient back in the original position, and estimated how closely (in distance) their group was able to achieve the original position in the region of interest. A worksheet guided students through the process, though student groups ultimately decided together how to complete the initial positioning, how to reproduce that positioning, and how to evaluate their work in a project-based learning format. Following the activity, the responsibilities that physicists hold in the CT simulation process were discussed, such as offering expertise on patient setup; designing new procedures; and acceptance testing, commissioning, and routine quality assurance of CT scanners.

2.B | Treatment planning activity
The second activity examined the treatment planning process. Acrylic sheets and printed paper copies of enlarged, anonymized patient CT images (eContour, University of California-San Diego) were used.
Trapezoidal shapes were cut from colored transparency material to represent therapeutic radiation beams. The isocenter was delineated on the transparency beams as well as on the acrylic sheets. Anatomical structures were traced on the acrylic sheets using color-coded markers to indicate both cancerous target volumes (to be "treated"

3.A | Immobilization and localization activity
Students were asked to decide, as a group, what would be the best way to ask a patient to position herself in order to take a CT scan of her shins. All students chose to ask their patient to lie down in the supine position on the table surface, and some groups requested that their patient remove her shoes. All groups created an outline of the patient on the classroom table surface using painter's tape. After the imaging (initial) positioning session concluded, and the patient returned for the treatment (second) alignment, students were asked to decide what region of their patient was the best aligned to its original position, and to quantify the accuracy of this alignment (in cm). For the imagined bilateral tibia treatment, most students focused on the lower legs and estimated an accuracy between 1 mm and 2 cm. Photographs of student teams working on the project are included in Fig. 3. The student

3.B | Treatment planning activity
Student groups were supplied with materials to design a treatment irradiation geometry for a single treatment site. Each small group worked with a different cancer site treated using radiation, including brain, breast, esophagus, testicle, larynx, oral cavity, pancreas, and prostate. Midway through the activity, each student group traded materials with another group and discussed beam placement strategies among themselves. Photographs of students engaging with the materials are included in Fig. 4. All student groups successfully identified strategies to include the target region in their treated area, while spreading out dose to healthy tissue and avoiding critical structures when possible. In their worksheet responses, students commented on anatomical structures that should not be irradiated, and in the wrap-up discussion, students speculated about possible risks involved in irradiating anatomical structures listed on their group's materials. Students identified required compromises as well as challenges involved in irradiating given target geometries.

3.C | Student reflections
To conclude the activities, students were asked verbally as well as in a written survey to compare their knowledge of medical physics and radiation therapy before participation in the activities to after participation. Although most students had not heard of medical physics prior to participation, 100% of students responded via the survey that they were aware of the field following the activities. Furthermore, 75% of students responded affirmatively to the question, "after these activities, do you feel more interested in careers in physics, engineering, or medicine?" Students who participated received certificates of achievement indicating they qualified as medical physicists in training.  Secondary feedback from parents (who were not in attendance) was positive, with observations including, "This new topic […] was reported 'amazing'…it's a yes to add for next year," "she learned about a job she'd never even thought of," and "the activities were A++." One parent's assessment included paraphrased comments from the student participant: "It was so cool.
[…] What we learned was so amazing. It was all about radiation for cancer treatment. How to plan, measure, and deliver the radiation. It was like being at the world's fanciest private school."

| DISCUSSION
Though diverse organizations, including in science and engineering, tend to outperform their more homogeneous counterparts, 15 23 and approximately half of all cancer patients receive radiation therapy during their course of treatment. 24 Though millions of patients benefit from their work, medical physicists often remain behind the scenes, and even many patients receiving radiation therapy are not familiar with the physicists contributing to their care. [25][26][27] It is therefore unsurprising that many students are not knowledgeable about the career opportunities related to this field: when surveyed high school students were asked to list three possible careers at a hospital, many students struggled to identify options beyond nurses and doctors. 28 Targeted outreach efforts may help address this unawareness. Many medical physicists find their field to be rewarding, with the majority of surveyed physicists expressing satisfaction with their jobs and reporting a feeling of accomplishment derived from their careers. 29 As a challenging and rewarding career choice, medical physics may be used as an example of possible future opportunities to students who previously may have never heard of the field, including members of student groups traditionally underrepresented in STEM. The activities described here are inexpensive and straightforward to implement and may be adapted and used for further outreach applications by interested physicists.

4.A | Future work
Though UW-Bothell's Inspire STEM Festival has been discontinued, future work will include delivery of these lesson plans again for the Burke Museum's Girls in Science Program in the 2019-2020 school year. In addition, these workshops will be delivered for a third program: the Girls in Engineering, Math, and Science (GEMS) Program through the Seattle Chapter of the Association for Women in Science.
GEMS offers free, STEM-based after-school programming for femaleidentified students in grades 7-8 enrolled in Seattle Public Schools.
GEMS after-school sessions are designed to encourage students to work in groups to complete hands-on, workshop-based activities.
Because the intended audience and classroom format are similar across the three programs, it is expected that the lesson plans described here will require minimal revision prior to delivery at GEMS.

| CONCLUSION
Detailed lesson plans were developed using two learner-centered, active-learning educational activities giving an introduction to careers in medical physics and radiation therapy. The lesson plans were designed to accommodate a middle school learning audience, using low-cost or donated equipment. The workshops were successfully delivered at two different educational outreach programs, for students in grades 6-8. A third program will be added in future work.

CONFLI CT OF INTEREST
There are no relevant conflicts of interest to disclose.

R E F E R E N C E S
1. Falkenheim J, Burke A, Muhlberger P, Hale K. Women, minorities, and persons with disabilities in science and engineering. Technical