The field of Medical Dosimetry involves the measurement and calculation of dosage for the treatment of cancer patients, thereby making medical dosimetrists vital members of the radiation therapy team.

After a tumor is located in a patient, dosimetrists use the physician's instructions to calculate the radiation dosage. Dosimetrists explain procedures to patients and then fit patients with devices to keep them comfortable and immobile during treatment. They may also be involved in research and the development of new therapy techniques.