Dosimetry is the scientific determination of the amount, rate, and distribution of radiation emitted from a source. Using a computer, the dosimetrist will help your radiation oncologist determine the exact area to be treated and where the radiation beams will enter and exit your body. Your general health and the size, type, and location of the tumor are a few factors considered when creating a treatment plan for you. After dosimetry, you may need to return to simulation for more measurements.