Radiation absorbed doses from Co-57- and Co-55 bleomycin.

Organ radiation doses to the adult patient after intravenous injection of Co-57- and Co-55 bleomycin were calculated using the MIRD methods. From these data somatically effective total-body doses for these radiopharmaceuticals were derived. Source organs are the bladder, kidney, and liver, and the remainder of the body. Residence times, i.e., cumulated activities per unit of injected radioactivity, were derived for each source organ, with their standard deviations, from measurements of Co-57 bleomycin clearance in a small number of patients. Target organs are the gonads and all organs that contribute to the somatically effective total-body dose. For Co-57- and Co-55 bleomycin the somatically effective doses are 0.26 +/- 0.03 rad/mCi (70 +/- 9 mu Gy/MBq) and 0.63 +/- 0.09 rad/mCi (171 +/- 23 mu Gy/MBq), respectively. The influences of the Co-56 impurity in Co-55, and of the Fe-55 daughter of Co-55 are discussed.