Transfer of radioactive substances to the human body

It has been of increasing importance to work out more realistic methods for estimating radiation dose to man arising from the radioactive contamination of environment. In view of this requirements, mass of organs and other characteristics of the normal Japanese was reviewed with an emphasis on the establishment of Reference Japanese Man. Considerable differences were shown in the relative weight of organs to the total body weight as well as mass of some organs important in dose estimation. Differences were pointed out in the consumption rate and major origin of fat and some minerals, i.e. calcium. Customary consumption of marine algae was confirmed to be also characteristic to the Japanese population. Importance of stable element analyses in radiological protection was discussed in view of the uptake rate, transfer from blood to tissues and bodily distribution of radionuclides, which is scarcely to be studies by radioisotope administration particularly for infants and adolescents. Radioiodine metabolism in the normal Japanese was studied and the influence of marine algae major source of stable iodine in the diet on the maximum uptake rate of 131I in the thyroid and the biological half-life was determined. The use of a transformation method in the application of MIRD dosimetry to Japanese was carried out. Lower annual limit of intake for 131I was suggested. These indicates the practical effectiveness of establishing Reference Japanese Man and related data in radiological protection. (author)