A new approach for the calculation of critical organ dose in nuclear medicine applications.

The geometrical factor that is calculated to keep in mind the radiation source and detector position is rather frequently used in radiation measuring and calculating methods. In this study, using the geometrical factor is intended to suggest a new model to measure the absorbed dose in nuclear medicine applications. Therefore, the source and target organ's geometries are accepted to be disc and parallel to each other. In this manner, a mathematical model for the geometry of these discs is proposed and a disc-disc geometry factor is calculated. Theoretical calculations have been carried out with the MIRD (medical internal absorbed dose) method, which is widely used to the absorbed dose calculations in nuclear medicine. Absorbed radiation dose is separately calculated for a target organ, which is the testis, with disc-disc geometry factor model and MIRD model. Both the results are compared and the results of disc-disc geometry factor model are shown to be harmonious and acceptable with the results of MIRD model.