Medical Dosimetrist

Medical Dosimetrist Job Description


The medical dosimetrist works as a vital member on the radiation oncology team. Radiation therapy involves treating cancer through a directed radiation beam or the insertion of radioactive seeds into or near a cancerous tumor. This therapy is designed to help shrink the tumor, but it can also cause damage to surrounding healthy tissues and organs. The job of the medical dosimetrist is to ensure that radiation treatment does the most good with a minimal amount of harm to the patient.

Radiation oncology teams usually include a radiation oncologist, a medical dosimetrist, a medical physicist, radiation therapists and nurses. When radiation therapy is prescribed for a cancer patient, a medical dosimetrist is responsible for determining exactly how to deliver the prescribed dose of radiation.

The medical dosimetrist first uses a three-dimensional computer model to calculate the exact location of the tumor and how to best distribute the radiation. Beam modification devices may be used to better target the radiation, thus minimizing the damage to surrounding tissues. To protect the patient’s body against exposure in non-cancerous areas, specialized equipment may be used to immobilize or cover body parts.




The medical dosimetrist is responsible for running computer simulations before the patient receives treatment, in order to make needed adaptations. This procedure is designed to make sure the plan will work as designed before the patient is exposed to it. The medical dosimetrist will then supervise the radiation therapist as he or she implements the treatment plan. The plan for radiation treatment may include only one dose or it may require several treatments to be scheduled over days or weeks.

According to the American Association of Medical Dosimetrists (AAMD), common responsibilities of medical dosimetrists include:

  • Designing radiation treatment plans to deliver precise levels of radiation doses with optimal beam geometry.

  • Identifying and contouring normal and dose-limiting structures by utilizing images from one or more data sets.

  • Creating and transferring reference images and localization markers for portal verification and treatment delivery.

  • Using specified imaging devices, such as CT, MRI, and PET scans, to supervise, perform, or assist in simulations or tumor localization.

  • Planning and implementing the fabrication of compensation filters, wedges, custom shields, and other beam-modifying devices.

  • Performing calculations to ensure accurate delivery of the prescribed radiation dose.

  • Documenting all pertinent information in patient records.

  • Verifying the mathematical accuracy of all calculation by an approved method.

  • Providing support and assistance to the medical physicist.




Good communication is a necessary skill for a medical dosimetrist. He or she must be able to pay close attention to the radiation oncologist in order to understand the treatment goals. The medical dosimetrist must accurately document the treatment plan, and must be able to clearly explain the plan to the radiation therapist who will be responsible for implementing the course of treatment.


Working Conditions


A medical dosimetrist will usually work a normal 40-hour week in a cancer treatment center or hospital. Medical dosimetrists use computers to design radiation treatments and test the effectiveness of the treatment. They are required to precisely document treatment plans, a responsibility that takes a good deal of time. They frequently consult with physicians, with patients and their families and with the radiation oncology team.

The very nature of this work places the medical dosimetrist in close proximity to radioactive materials. Proper safety precautions are absolutely necessary to minimize exposure.



How to Become a Medical Dosimetrist:


1. Earn a Bachelor's Degree (4 Years)


Aspiring medical dosimetrists should first pursue a bachelor's degree program in radiation therapy, or a closely related field such as biology, microbiology, physics, chemistry, biochemistry, or premed. 


The preparation timeline below provides an example premed undergraduate curriculum:


Grade Level Example Courses

Freshman Year


  • Health Care Systems
  • Biology I & Lab
  • Biology II & Lab
  • Calculus I
  • Chemistry I & Lab
  • Chemistry II & Lab
  • English I
  • Psychology 
  • Humanities Requirements
  • Electives

Sophomore Year

  • Public Health
  • Anatomy & Physiology I & Lab
  • Anatomy & Physiology II & Lab
  • Statistics
  • Organic Chemistry I & Lab
  • Organic Chemistry II & Lab
  • Basic Skills for Healthcare
  • Nutrition
  • Humanities Requirements
  • Electives

Junior Year


  • Healthcare Communication
  • Healthcare Professional Writing
  • Genetics & Microbiology I & Lab
  • Physics I & Lab
  • Physics II & Lab
  • Problems in Healthcare
  • Healthcare Research
  • Biochemistry I & Lab
  • Humanities Requirements
  • Electives

Senior Year

  • Health in the US
  • Health Education and Planning
  • Healthcare Management
  • Health Policy
  • Capstone
  • Remaining Requirements
  • Remaining Electives


2. Complete a JRCERT Accredited Medical Dosimetry Program (1 Year)


The educational program to become a medical dosimetrist is rigorous. It requires a thorough understanding of the effects of cancer on the body and how radiation is used as a treatment for cancerous cells. A medical dosimetrist must be able to calculate the exact dose of radiation needed to achieve the objectives of the treatment plan. Higher-level math is required to accurately calculate dosages. Computer-generated models must be used to visualize bodily structures, thus requiring an ability to accurately interpret these images.

A medical dosimetrist must learn all about the equipment used in radiation therapy and the proper techniques to deliver radiation treat in a safe manner. Protecting the safety of the patient and other medical personnel is paramount.

Classroom education as well as clinical practice is included in the program of study.


Search JRCERT Accredited Medical Dosimetry Programs


3. Become a Certified Medical Dosimetrist


Medical dosimetrists must pass an examination and meet continuing education requirements in order to maintain certification through the Medical Dosimetrist Certification Board (MDCB).



Salary Outlook