In nuclear medicine bone imaging, which statement is true regarding technetium and gallium?

In nuclear medicine bone imaging, which statement is true regarding technetium and gallium?

• A. Technetium binds to WBCs and is seen in areas of inflammation
• B. Gallium binds to hydroxyapatite and shows high bone turnover
• C. Technetium binds to hydroxyapatite and is seen in areas of high bone turnover
• D. They should be given together with gallium first

Answer: (C)

In bone imaging, technetium-labeled diphosphonates bind directly to hydroxyapatite in bone, and their uptake rises with osteoblastic activity and bone turnover. That’s why technetium-based bone scans highlight areas where bone remodeling is occurring, such as fractures, metastases, or healing lesions. Gallium, on the other hand, localizes to inflammatory and some neoplastic processes mainly through mechanisms like transferrin binding and increased vascular permeability, not by attaching to hydroxyapatite. It’s used more for soft-tissue infection and certain tumors rather than measuring bone turnover. Therefore, the true statement is that technetium binds to hydroxyapatite and is seen in areas of high bone turnover. The idea that technetium binds to WBCs, that gallium binds to hydroxyapatite, or that they must be given together (with gallium first) doesn’t reflect how these agents operate in clinical imaging.

In bone imaging, technetium-labeled diphosphonates bind directly to hydroxyapatite in bone, and their uptake rises with osteoblastic activity and bone turnover. That’s why technetium-based bone scans highlight areas where bone remodeling is occurring, such as fractures, metastases, or healing lesions. Gallium, on the other hand, localizes to inflammatory and some neoplastic processes mainly through mechanisms like transferrin binding and increased vascular permeability, not by attaching to hydroxyapatite. It’s used more for soft-tissue infection and certain tumors rather than measuring bone turnover. Therefore, the true statement is that technetium binds to hydroxyapatite and is seen in areas of high bone turnover. The idea that technetium binds to WBCs, that gallium binds to hydroxyapatite, or that they must be given together (with gallium first) doesn’t reflect how these agents operate in clinical imaging.