InDose - An Internal Dosimetry Code Developed at Soreq

Estimation of doses to people exposed to ionizing radiation due to inhalation or ingestion of radio-active materials is often based on calculations of the activity in the tissues of the body and in excreta following a given intake. Comparison between these calculations and laboratory measurements of the activity in excreta or in tissues of the body enables estimation of the amount of radioactive material which entered the body and hence the expected committed doses. These calculations are based on a set of models recommended by the ICRP that describe the paths of the radioisotope in the body and provide the equations to calculate their transfer rates within the body and out of it. During the last decade the ICRP made major revisions in its recommendations regarding protection from ionizing radiation and in particular it recommended the use of new models for estimating doses due to inhalation and ingestion of radioisotope. Among the new models are that of the new respiratory tract presented in ICRP publication no. 66 and the biokinetic models for various radioisotopes which have been presented in publications 56 to 71. All the new models have been developed to enable dose estimation for the general public, including children. They are based on physiological processes in order to enable adjustment for age, gender, and physical condition. In a previous paper [4] we presented a new Internal Dosimetry code developed at Soreq (InDose) to enable making assessments based on these new models. Up to now, only the new model has been applied for dose estimations in generally available PC package codes (e.g., LUDEP-2 and Genmod), while the new biokinetic models have not. Recently, ICRP presented publication 78 [2] - which is a replacement of publication 54 - in which it gives monitoring data recalculated with the new biokinetic models. However, the data are only for acute or constant value chronic intakes. It employs the standard 5 vm particles in cases of intake by inhalation