Ga-67 Citrate Whole-Body Scan: Agent and Timing

This whole-body scan shows posterior and anterior views at two window settings. Based on the imaging appearance and normal biodistribution seen in the liver, spleen, and bone marrow, which radiopharmaceutical was most likely used and what is its standard imaging schedule?

1. ATc-99m sulfur colloid; whole-body images are acquired 30–60 minutes after IV injection to assess liver, spleen, and bone marrow distribution
2. BIn-111 pentetreotide; whole-body images are acquired at 4 hours and 24 hours post-injection to detect neuroendocrine tumor sites
3. CGa-67 citrate; whole-body images are typically acquired at 24, 48, and 72 hours after injection to allow blood-pool clearance and adequate lesion uptake
4. DTc-99m MDP; whole-body bone scan images are acquired 2–4 hours after injection once soft tissue background has cleared