Paper radiochromatography for evaluation of radiochemical purity and stability of [186gRe]Re- HEDP in biological samples after human administration

[186gRe]Re-HEDP is a radiopharmaceutical used for pain palliation in bone metastases from various primary tumors. The negatron emitter with <Eβ> = 357 keV 186gRe is suitable to irradiate cancer and inflammatory cells, but it needs labeling bis-phosphonates as vectors to reach target tissue. Paper radiochromatography was used to evaluate the radiochemical purity of [186gRe]Re-HEDP in radiopharmaceutical solution as well as in biological samples (serum and urine) from treated patients, in order to follow bone-targeting and excretion. Following the activity concentration in each sample vs. time it is effective to elaborate a bio-kinetic model of the radiopharmaceutical and to optimize administration protocols.