The Basic Principles in Assessment and Selection of Reference Doses: Considerations in Nuclear Medicine (invited paper)

The possible ways to optimise the relation between diagnostic information and patient absorbed dose differ between nuclear medicine and X ray imaging. In nuclear medicine, very little has been done to find an optimal dosage of radiopharmaceuticals. Current nuclear medicine methods are discussed in the light of the recent ICRP Publications and the new EU Patient Directive. The paper also discusses how reference levels for administered activity may be derived from patient studies. In order to eliminate the most inappropriate choices (too low or too high activities), knowledge of the current statistical distribution of administered activities may be helpful. Different methods to estimate the amount of activity that should be administered to children of various body sizes to guarantee the same image quality as for adults are also discussed. Examples of current activity levels for common nuclear medicine procedures, indicating the state of the practice, are given. (author)