RHENIUM-188(SN)HEDP FOR TREATMENT OF OSSEOUS METASTASES

Rhenium-188 (tin) hydroxyethylidine diphosphonate [Re-188(Sn)HEDP] is a new radiopharmaceutical that localizes in skeletal metastases and em its beta particles that may be therapeutically beneficial. Methods: it was evaluated by in vitro and in vivo testing in the laboratory, in a nimals and in humans using Re-188 from a variety of sources. it may be produced by a desk-top method developed previously for Re-186(Sn)HEDP using Re-188 produced through neutron irradiation of either enriched Re-187 or naturally occurring rhenium targets or the use of a W-188/Re -188 generator. Results: So long as the mass of rhenium in the Re-188- perrhenate to be processed into Re-188(Sn)HEDP is at least 100 mu g, s atisfactory radiochemical yields and purity may be obtained by all met hods, The Re-188(Sn)HEDP has biodistribution and radiation dosimetry c haracteristics that are similar to those noted previously for Re-186(S n)HEDP and appears to result in similar benefits and toxicities in pat ients with skeletal metastases. External radiation exposure monitoring indicates that, only 4 hr after a therapeutic administration of 1110 MBq (30 mCi) of Re-188(Sn)HEDP, average exposure rates at 1 meter from the patient would be only 0.5 mR/hr. Conclusion: Same-day, on-demand, outpatient therapy of disseminated skeletal metastases appears to be feasible with Re-188(Sn)HEDP.