Calcium-41 (41Ca) Chloride Aqueous Solution in Diagnosing Patients With Prostate Cancer and Bone Metastasis

OBJECTIVES: Primary * To measure the pharmacokinetics of a single oral dose of calcium-41 (41Ca) chloride aqueous solution (\^41Ca) over 18 months in patients with hormone-refractory prostate cancer and bone metastasis. * To correlate the \^41Ca-tracer kinetics with time to disease progression, skeletal-related events, and death. Secondary * To correlate modulations in baseline urinary \^41Ca clearance with changes in clinically relevant disease parameters, including isotope bone scan data and PSA. * To combine bone turnover assessments with \^41Ca and collagen/bone cell biomarkers with clinical imaging techniques, especially isotope bone scans, to provide improved stratification of disease stage. OUTLINE: Patients receive oral calcium-41 (41Ca) chloride aqueous solution (\^41Ca) on day 1. Some patients also receive oral calcium-46 (46Ca) chloride aqueous solution (\^46Ca). Urine and blood specimens are collected periodically for 18 months. Blood samples are assayed for bone collagen residues, bone alkaline phosphatase, and PSA. Urine specimens are assessed for \^41Ca/Ca. Isotope bone scintigraphy is use to measure radioactivity. After completion of study treatment, patients are followed up periodically for 3 years.