ABSTRACT
Ionizing radiation induces molecular changes leading to biological damage in living systems. This chapter presents concepts and methods used for assessing internal radiation dose from radionuclides administered systemically for medical therapies, including the treatment of cancer. It describes calculational dosimetry methods that may be used for meeting clinical research needs. The radiation dosimetry associated with high-dose radionuclide therapy is important for: evaluating tumor-uptake efficiency; treatment planning; limiting radiation doses to normal organs; and assessing the effectiveness of cancer therapy. Specialized dosimetric tools and computational methods are needed to support the dosimetry needs of a clinical research program. The chapter describes methods for estimating absorbed doses to human tumors and normal tissues. Normal tissues include the major organs, as well as intraperitoneal tissue surfaces, red marrow, and the intestinal tract. These methods use the Medical Internal Radiation Dose system; however, they also incorporate enhancements designed to solve specific dosimetry problems encountered during clinical studies.
