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

[(186)gRe]Re-HEDP is a radiopharmaceutical used for pain palliation in bone metastases from various primary tumors. The negatron emitter with = 357 keV (186)gRe 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 [(186)gRe]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.