32P-Sodium Phosphate or Orthophosphate, Na2H32PO4, is an older radiotherapeutic agent used in the palliation of bone pain in patients not responsive to the usual analgesics. This pain palliation agent is efficient in about 50% of prostate and breast cancer patients. Usual dose is around 7 mCi. Above 12 mCi side-effects (myelosuppression) become more important. Pain palliation generally occurs within 14 days and the mean duration of pain relief is about 5 months. 32P also has an application in Polycythemia Vera (PCV), a disease characterized by an overproduction of red cells. This disease can be treated either by phlebotomy, chemotherapy or 32P. Median survival increases to 10 to 15 years compared to 7–8 years with phlebotomy and 2 years without treatment.

Target/Mechanism: Bones

Leading Emitter: beta electrons (β)