Influence of pretreatment with 3-amino-1-hydroxypropylidene-1,1-bisphosphonate (APB) on organ uptake of At-211 and I-125-labeled amidobisphosphonatesin mice

To minimize nontarget organ uptake in animals receiving radiolabeled amidob isphosphonates, the influence of pretreatment with cold 3-amino-1-hydroxypr opylidene-1,1-bisphosphonate (APB, pamidronate) was studied. Three groups o f animals were given pure 3-[I-125]iodobenzamide-N-3-hydroxypropylidene-3,3 -bisphosphonate (IBPB) and 3-[At-211]astatobenzamide-N-3-hydroxypropylidene -3,3-bisphosphonate (ABPB) (control); co-injection of APE and IBPB/ABPB; an d 1 h preinjection of APE followed by IBPB/ABPB, respectively. A significan t reduction of uptake in normal tissue was observed, whereas the bone uptak e remained constant at 35-50%ID/g tissue. This study suggests that co- or p reinjection of pamidronate may reduce the normal organ radiation doses when using these radiohalogenated bisphosphonates for endoradiotherapeutic proc edures. NUCL MED BIOL 26;1:791-794, 1999. (C) 1999 Elsevier Science Inc. Al l rights reserved.