Dosimetrist

A dosimetrist is a member of a radiation oncology team who specializes in the operation of radiation equipment and calculations of dosages in cooperation with oncologists. According to the AAMD (American Association of Medical Dosimetrists), the Medical Dosimetrist is a member of the radiation oncology team who has knowledge of the overall characteristics and clinical relevance of radiation oncology treatment machines and equipment, is cognizant of procedures commonly used in brachytherapy and has the education and expertise necessary to generate radiation dose distributions and dose calculations in collaboration with the medical physicist and radiation oncologist.

Education

Medical Dosimetry programs are scattered across the U.S. accepting an average of 2-3 students per program. Admission to such a program is highly competitive and extensive knowledge and understanding in Medical Physics and mathematics is crucial to success in the field. The standard (and the fastest) route is to obtain a bachelor's or master's degree in Medical Dosimetry (highly competitive, about 15 are being accepted each year in the U.S.). Though you can still become a qualified dosimetrist through other routes such as obtain a bachelor's degree in Medical Radiation Sciences in Radiation Therapy first and work for a few year afterwards to build up the experiences to become eligible for the CMD examination [http://www.mdcb.org/examinfo/eligibility.htm] ) Medical Dosimetry Certification is optional and is not a requirement by any state. This voluntary exam certification has a very low pass rate and is not considered a must to obtain a position within the field, although more and more cancer centers are requiring the CMD certification now.

The Profession

After the Radiation Oncologist has consulted with the patient on their plan of treatment, he/she will write a prescription of radiation dose to a defined tumor volume. The medical dosimetrist will then design a treatment plan by means of computer and/or manual computation to determine a treatment field technique that will deliver that prescribed radiation dose. When designing that plan, also taken into consideration are the dose-limiting structures.

The medical dosimetrist maintains a delicate balance between delivering the prescription the physician has written while ensuring the patient will not lose important healthy organ function. He/she performs calculations for the accurate delivery of the Radiation Oncologist's prescribed dose, documents pertinent information in the patient record, and verifies the mathematical accuracy of all calculations using a system established by the Medical Physicist. In many institutions, the medical dosimetrist also has the ability to execute planning for intracavitary and interstitial brachytherapy procedures, the application of specific methods of radiation measurement including ion chamber, thermoluminescent dosimeters (TLD), or film measurement.

Following the planning process, the patient will have a simulation for tumor localization to ensure reproducibility of treatment set up and plan delivery. Here, it may be necessary to produce moulds, casts, and other immobilization devices for accurate treatment delivery. A medical dosimetrist may supervise, perform, or assist in this process. The medical dosimetrist will then work with the radiation therapists in the implementation of the patient treatment plans including: the correct application of immobilization devices, beam modification devices, approved field arrangements, and other treatment variables.

The advancements in computer technology place dosimetrists at the forefront of many new processes. Using imaging modalities such as CT scans, alone or in combination with MRI or PET scans, 3-D computerised treatment-planning that allows the delivery of higher doses of radiation to a tumor while lowering the doses to the sensitive structures around it. In some environments the medical dosimetrist plays a part in cutting edge clinical research for the development and implementation of new techniques in cancer treatment. Medical dosimetrists may also be active in teaching and research roles in an academic setting.

In 2007, the average salary for medical dosimetrists was close to 90,000$ according to the survey done by its professional association.