How to Become a Medical Dosimetrist

What is dosimetry?

Lead dosimetrist Kenn Florell looks over a cancer patient's image scan to help plan a radiation treatment at Cape Fear Valley Cancer Center August 4, 2010 in Fayetteville, North Carolina.
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A medical dosimetrist is a certified professional therapist who is part of the radiation oncology team, helping to treat cancer patients via radiation therapy. They are responsible for the treatment plan that ensures the correct dosage of radiation reaches the targeted tissues while protecting healthy tissue.

Dosimetrists typically work in a hospital or cancer center. They must be able to work well as part of a medical team, consulting with professionals including physicians (radiation oncologists), radiation therapists, oncology nurses, and medical physicists.

Requirements to Become a Medical Dosimetrist

The typical path to becoming a medical dosimetrist is for a registered radiation therapist to apply to attend a Medical Dosimetry JRCERT accredited program, which will last at least 12 months. Some of these programs may accept applicants who have a bachelor's degree with physical science pre-requisites. Accredited schools have a competitive admissions process. They also usually require that the applicants complete an observation of medical dosimetry so they understand the nature of the profession.

Upon completion of this year-long program, the candidate can apply to take the certification exam from the Medical Dosimetrist Certification Board (MDCB) and earn their CMD (Certified Medical Dosimetrist) designation. Previously, there was a path to certification based on clinical experience, but as of 2017 only graduates from the 12-month accredited programs who hold a bachelor's degree can take the certification exam.

Job Responsibilities and Required Skills for Dosimetrists

According to the American Association of Medical Dosimetrists (AAMD), the medical dosimetrist is responsible for the "radiation dose distributions and dose calculations" used in radiation therapy, which is typically a daily regimen over the course of several weeks, depending on the type and location of the patient's cancer. Dosimetrists must have thorough knowledge in the areas of cancer treatment and brachytherapy. The dosimetrist helps deliver the radiation in the precise doses necessary to treat cancer without harming healthy tissue and organs near the tumor. Designing the treatment plan for the cancer patient is a key responsibility of the dosimetrist.

Dosimetrists must be critical thinkers, and be able to analyze data and implement a course of therapy based on the data, such as images and measurements. Dosimetrists must have strong math skills, as they perform calculations as well as verify the accuracy of calculations in determining the course of treatment to deliver the precise dosage of radiation to the pinpoint location of the tumor.

Additionally, dosimetrists must have strong technical skills, as they are often responsible for ensuring the calibrations and functionality of medical equipment used in radiation therapy, including an ion chamber, or thermoluminescent dosimeters (TLD), according to the AAMD website. Technology is constantly changing in radiation oncology, requiring a dosimetrist to keep up with evolving treatment methods.

How Much Do Dosimetrists Earn?

According to, the salary range for dosimetrists ranges from about $76,500 to $120,000 with an average of around $96,000 annually. With additional experience, salaries can reach over $130,000.

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