Dosimetrists

Dosimetrists are radiation therapy professionals who specialize in calculating and optimizing the doses delivered to cancer patients undergoing radiation treatment. Working under the supervision of radiation oncologists and medical physicists, they convert a physician’s prescription into a practical plan that defines beam arrangements, energies, and dose limits to maximize tumor control while protecting normal tissue.

Their duties include creating and refining treatment plans for techniques such as 3D-conformal radiotherapy, IMRT, VMAT, SBRT, and brachytherapy; performing dose calculations; selecting beam geometries; computing monitor units; and performing plan quality assurance. They collaborate with physicians, physicists, and therapists, review imaging, delineate target volumes and organs at risk, and ensure plans meet treatment objectives and safety standards.

Education and certification: Most dosimetrists hold a bachelor’s degree in medical dosimetry, medical physics, physics, or a related field, and complete an accredited dosimetry program. In the United States, the common credential is Certified Medical Dosimetrist (CMD) from the Medical Dosimetrists Certification Board.

Work settings and tools: Dosimetrists are employed in hospitals, cancer centers, and academic medical centers. They work with computer-based planning systems and imaging data from CT, MRI, and PET. They play a key role in quality assurance to verify dose distributions and treatment parameters before and during patient treatment.