The Complete Guide to Becoming A Medical Dosimetrist

Chapter 1: What Does a Medical Dosimetrist Actually Do?

Let's start with the moment that defines this job. A 58-year-old man with lung cancer is lying on a CT scanner table. The images of his chest — his tumor, his lungs, his heart, his spine — are loading on a computer screen in a dimly lit office across the hall. That office belongs to you, the medical dosimetrist. Over the next two hours, you will trace the edge of his tumor on every single slice of the scan, design a set of radiation beams that hit it from several angles, and then carefully shape each beam so it delivers a killing dose to the cancer while sparing his heart and healthy lung tissue. When you're done, a physicist will double-check your math, and a radiation oncologist will approve your plan. The patient will start his treatments a few days later, five days a week for six weeks. Every one of those thirty treatments will be delivered using the blueprint you created today. That is the job in its purest form: you are the person who designs how radiation is delivered to a patient.

Medical dosimetrists are the bridge between the doctor's prescription and the machine that delivers the treatment. The radiation oncologist decides the dose — say, 60 gray (a gray is the unit of absorbed radiation dose, and 60 is a typical curative dose for lung cancer). The dosimetrist figures out how to actually get that dose to the