GUEST CONTRIBUTOR:
Linnae Campbell MSHA, MS, CMD R.T.(R)(T)
Certified Medical Dosimetrist
Northwestern Medicine
You might be thinking, “Happy WHAT?!” Medical Dosimetrists are at the center of the Radiation Oncology team.1 Patients with a cancer diagnosis entrust their health and safety to their Radiation Oncology team. Ultimately, Medical Dosimetrists complete technical tasks on computers to align imaging data, outline body organs, and create a treatment plan with Physician supervision.
How to Become a Medical Dosimetrist
Since the field isn’t well known, you might be wondering how one ends up becoming a Medical Dosimetrist. Someone may have first- or second-hand experience with radiation treatment. The individual might have been attracted to the field thanks to the work of the American Association of Medical Dosimetrists (AAMD), the professional organization for Medical Dosimetrists with a mission to further the profession.2 My exposure to the field came from job shadowing in a Radiation Oncology Department during Radiologic Science (X-Ray) clinicals. Those that enjoy topics like biology, anatomy, physics and math may thrive in this field. After completing a JRCERT-accredited Medical Dosimetry program, graduates are eligible to sit for the Medical Dosimetrist Certification Board (MDCB) exam.3 Certified Medical Dosimetrists partake in continuing education to maintain certification for the duration of their career. NAPT and AAMD provide great networking and educational resources for Medical Dosimetrists. Proton Medical Dosimetrists make up a small portion of the 4,500+ practicing Certified Medical Dosimetrists.4
Proton Dosimetry Training
Onboarding a new Proton Medical Dosimetrist can take well over a year. There are acronyms and devices to learn about, like PBS to describe Pencil Beam Scanning treatment delivery, a cyclotron to generate the proton beam, snouts for treatment field sizes, and range shifters that bring the dose proximal to the patient surface. Proton nuances must be appreciated, like how the beam will interact with body tissues and devices. With proton millimeter accuracy, there is an art to creating a treatment plan that strikes the balance of covering the disease while sparing nearby organs. After creating a treatment plan, robustness checks are completed to understand if the plan can withstand uncertainty scenarios such as a shift in patient position or breathing motion. Even with robustness checks, adaptive treatment plans are sometimes necessary to account for anatomical changes in the patient. The expertise of a well-trained Proton Medical Dosimetrist can contribute to higher-quality treatment plans and be an ally in patient safety.
Teamwork in Protons
First the Physician will delineate a target which is the disease site. Individual patient demographics must be taken into consideration during the plan generation. Each case is unique because every patient is different, whether it’s proximity of vital organs to the target, prior radiation cases, or re-irradiation. The Medical Dosimetrist creates the plan by inputting multiple objectives into a treatment planning system to increase coverage to the target and minimize dose to nearby organs. Medical Dosimetrists may generate multiple plan options for a patient. The Medical Dosimetrist and Physician collaborate to evaluate the plans. The Physician will decide if it’s better to favor target coverage or spare overlapping organs. Safe and effective hand-offs are a daily occurrence in the field. This is what makes Medical Dosimetry the glue of the radiation oncology team. Once the plan is selected, the Medical Dosimetrist needs to tell the Medical Physicist checking the plan about any highlights of the case. For example, the Physician may have directed the Medical Dosimetrist to bring down the total dose after seeing a plan summary of the previous treatment and the current proton plan. After the initial Physics check, the plan is ready for final review by the Physician. The Medical Dosimetrist needs to communicate: any concerns from the Physics check, what beam angles were utilized, verify the prescription, and evaluate the dose to the target and nearby organs. The treatment plan on the CT is reviewed slice by slice! Next, the Quality Assurance Physicists will run the plan on the treatment machine utilizing a phantom. We do quality assurance to verify doses because once the dose is delivered, we can’t take it back. Meanwhile, a report is created to document the plan for the radiation therapist/s to cross-check. All these tasks require working together with different departments and communicating vital information to keep the patients safe.
One year for Medical Dosimetrist’s Day, someone showed a picture of their new coffee cup imprinted with the words “Medical Dosimetrist, basically a Wizard.” I don’t know about all that, but it’s an honor to create proton Medical Dosimetry magic that gives our patients hope.
References
- National Medical Dosimetrists’ Day. (AAMD). Accessed August 15, 2024. https://www.medicaldosimetry.org/about/national-medical-dosimetrist-s-day/.
- Who is AAMD? American Association of Medical Dosimetrists (AAMD). Accessed August 15, 2024. https://www.medicaldosimetry.org/about/who-is-aamd/.
- Medical Dosimetrist Certification Board (MDCB). Accessed August 15, 2024. https://mdcb.org/certification-exam-information/eligibility
- About Dosimetry. Medical Dosimetrist Certification Board (MDCB). Accessed August 15, 2024. https://mdcb.org/about-mdcb/about-dosimetry.
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