Application of radioactive substances in research in nuclear medicine: current trends and radiation exposure to the study subjects

Aim: Analysis of the application of radioactive substances in research in t he field of nuclear medicine in human beings and of the resulting radiation exposure to study subjects. Methods: Assessment of applications for approv al submitted is accordance with Paragraph 41 of the Radiation Protection Or dinance, evaluated by the Federal Office for Radiation Protection together with the Federal Institute for Pharmaceuticals and Medical Products, within the period from 1997 to 1999. Results: The focus of the studies on the dia gnostic application of radioactive substances in medicine evaluated has, si nce 1998, shifted from oncological to neurological and psychological aspect s, while, at the same time, the number of PET studies increased constantly. The proportion of healthy study subjects included in the diagnostic studie s increased from 7 to 22%. The number of therapeutic applications of radioa ctive substances has, since 1997, undergone a three-fold increase, and in t he process of this, the focus of attention lay within the area of radioimmu no-therapy and endovascular brachytherapy The effective dose was, among up to 49% of the investigated healthy study subjects higher than 5 mSv, and am ong up to 6% of these subjects was at levels of over 20 mSv. Up to 22% of t he patients received, within the scope of diagnostic studies, an effective dose of between 20 and 50 mSv. An exceeding of the 50 mSv limit occurred am ong up to 3% of the patients. Conclusions: In spite of the increasing numbe rs of PET applications, conventional nuclear medicine has maintained its im portance in the field of medical research. Further developments in the area s of radiochemistry and molecular biology led to an increase in the importa nce of radio-immuno therapy. The evaluation of new radiopharmaceuticals and the extension of basic biomedical research, resulted in an increase in the proportion of healthy study subjects included in the studies. The radiatio n exposure among subjects resulting directly from the studies showed, for t he period of evaluation, an overall trend towards reduction.