Stimulation of Technetium Activity in Human Body Organs After Injection Using MIRD and ICRP Models

Abstract

Internal dosimetry deals with the measurement of the radiation dose absorbed internally by an organ after the administration of isotopes for diagnosis and treatment. The purpose of this research was to evaluate bladder-urine transfer coefficient impact on the bladder technetium activity in the MIRD bio kinetic model and propose a simplified biokinetic model using the ICRP 134 model. The residence time in the bladder and kidneys was determined using scans of five volunteer patients at three different time points (1 h, 2 h, and 3 h post-injection). To quantify activity in the kidneys and bladder, the conjugate-view method was applied to the imaging data. In the present study technetium activity has been calculated in human organs using the MIRD et ICRP bio-kinetic models. The theoretical results were obtained by simulation on the MatLab software of the matrix equations obtained from different equations of the quantity of technetium in the different organs used in the bio-kinetic models. The study showed that it is important to take into account the transfer coefficient between the bladder and urine to reduce the fraction of technetium in the bladder. The ICRP model and the proposed simplified model predict technetium fractions better than the MIRD model three hours after injection. The study also showed that the ICRP model and the proposed simplified model are in agreement in predicting the technetium fraction in the bladder and kidneys.