Quantitative Bone Single-Photon Emission Computed Tomography for Prediction of Pain Relief in Metastatic Bone Disease Treated With Rhenium-186 Etidronate

PURPOSE: To calculate radiation doses of rhenium-186 (186Re) etidronate in painful bone metastases using quantitative bone single-photon emission computed tomography (SPECT) and to determine the threshold dose for predicting pain relief. We also wanted to determine whether technetium-99m (99mTc) methylene diphosphonate (MDP) concentrations predict radiation doses of 186Re etidronate in painful lesions. MATERIALS AND METHODS: Forty-eight patients with breast and prostate cancer were evaluated. Patients received therapeutic doses of 186Re etidronate. The area under the pain over time curve (AUPC) was measured for 8 weeks after treatment. Response was calculated as the percentage of change in AUPC. Quantitative bone SPECT (QBS)–measured concentration of 186Re etidronate was used for calculating radiation doses. Receiver operating characteristics curve analysis determined the radiation dose threshold that best separated responders from nonresponders. SPECT-measured concentration of 186Re etidronate in the uri...