ABSTRACT
Estimating radiation dose to organs or tumors in the body is important in determining injected activity limits for radiopharmaceuticals and in targeted radiotherapy treatment (TRT) planning. This chapter will concentrate on the latter application and the potential improvements in the accuracy of dose estimation that singlephoton emission computed tomography (SPECT)/computed tomography (CT) provides. This improved accuracy results from the existence of a CT image registered to planar or SPECT images that can both provide the improved image quantitation and allow the use of improved dose estimation methods.
