Modeling radiation dose and effects from internal emitters in nuclear medicine: From the whole body to individual cells

In nuclear medicine, proper application of radiation protection principles depends on balancing the potential risks of exposure to ionizing radiation against its possible benefits. Average doses to organs, in diagnostic or th erapeutic applications, are not always representative of the doses received at the tissue or cellular level. Therefore, understanding of the relations hip between the overall biological effect and absorbed dose delivered by th e radiopharmaceutical may require study of doses at the organ, tissue, or c ell level. In this paper. we review current models for radiation dose asses sment, with consideration of the different models and assumptions employed for study at all levels of investigation.