ABSORBED DOSE CALCULATIONS IN HAVERSIAN CANALS FOR SEVERAL BETA-EMITTING RADIONUCLIDES

A mathematical model of a Haversian canal was used to calculate absorb ed dose factors for Sr-90, Y-90, Ca-45, Sr-89, P-32, I-131 and Sm-153. The regions of interest considered in this study were the blood canal , the wall or bone surface and the bone matrix. The source regions wer e the blood canal ard the bone surface. Absorbed dose calculations wer e performed with the EGS4-PRESTA Monte Carlo transport code. Dose fact ors were calculated for Haversian canals of 5-mum to 50-mum radius. Th ese data are also tabulated so that dose factors can be evaluated for other radii. An example is given in which these data are used along wi th a biokinetic model of a radioactive material in bone to assess dose s from diagnostic and radiotherapy procedures.