EVALUATION OF THE EFFECT OF CHANGE IN THE RADIOSENSITIVE TISSUE WEIGHTS LISTED IN THE ICRP IN ESTIMATE OF EFFECTIVE DOSE

摘要

For photons and electrons, the effective dose by gender is a weighted sum of the absorbed doses in radiosensitive organs and tissue of the human body. Effective dose is estimated using Exposure Computational Models (ECM) of both genders for the same age group. The FSTA and MSTA ECMs were developed by researchers from DEN/UFPE and consist of voxel phantoms representing adults coupled to EGSnrc Monte Carlo Code, which, in the folder designed for users of EGS, codes were added to simulate some radioactive sources. The reports 60 and 103 of the ICRP provide the factors that weigh the radiosensitivity of organs and tissues (w_T) required to estimate the effective dose. The two lists were placed in the FSTA and MSTA to simulate radiodiagnostic examination in different regions of the body (cranium, abdomen and thorax). The dosimetric data produced allowed an analysis of the effect of the change in the w_T from the report 60 to the 103. The highest mean percent relative error, 64.3%, occurred in the results for the cranium due to the increase of the w_T for most of the organs and tissues in the head and trunk in the updated list. In this case, it can be concluded that the values of the effective dose with the w_T of the ICRP 60 were underestimated. Other types of simulators of radioactive sources can be used in investigating this problem and other variables related to the phantom can be considered for that proposes a w_T's list specific for the Brazilian population or recommend unrestricted use the ICRP data.