Red marrow dosimetry for radiolabeled antibodies that bind to marrow, bone, or blood components

Hematologic toxicity limits the radioactivity that may be administered for radiolabeled antibody therapy. This work examines approaches for obtaining biodistribution data and performing dosimetry when the administered antibod y is known to bind to a cellular component of blood, bone, or marrow. Marro w dosimetry in this case is more difficult because the kinetics of antibody clearance from the blood cannot be related to the marrow. Several approach es for obtaining antibody kinetics in the marrow are examined and evaluated . The absorbed fractions and S factors that should be used in performing ma rrow dosimetry are also examined and the effect of including greater anatom ical detail is considered. The radiobiology of the red marrow is briefly re viewed. Recommendations for performing marrow dosimetry when the antibody b inds to the marrow an provided. (C) 2000 American Association of Physicists in Medicine. [S0094-2405(00)01009-9].