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Comprehensive and Detailed Explanation: The usual adult dose of Tc-99m medronate (MDP) or oxidronate (HDP) for a whole-body bone scan is 20–30 mCi (740–1110 MBq), with many laboratories using approximately 25 mCi. Lower activities may be used in pediatric patients (scaled by weight or body-surface area) or when SPECT/CT is the primary examination. Higher activities increase radiation dose without proportional diagnostic benefit. Proper hydration and frequent voiding after injection reduce bladder and radiation dose to the pelvic organs. Imaging is performed 2–4 hours post-injection to allow soft-tissue clearance. Technologists must verify the prescribed activity, assay the dose in a calibrated dose calibrator, and confirm patient identity and pregnancy status before administration. Dose ranges may be adjusted for specific clinical indications or institutional protocols, but 15–30 mCi remains the widely accepted adult range.