What is a common method for imaging infection or inflammation using Tc-99m?

• A. Using Tc-99m MDP for bone scans
• B. Using Tc-99m HMPAO for white blood cell labeling
• C. Using Tc-99m Sestamibi for cardiac evaluation
• D. Using Tc-99m EDTMP for thyroid imaging

Answer: (B)

Using Tc-99m HMPAO for white blood cell labeling is a common method for imaging infection or inflammation because it allows visualization of areas where there is an active immune response. HMPAO (hexamethylpropyleneamine oxime) is a radiopharmaceutical that is utilized to label white blood cells, specifically for the diagnosis of infections, abscesses, and inflammatory conditions. When white blood cells are labeled with Tc-99m HMPAO, they can accumulate in regions of infection or inflammation due to the increased blood flow and the attraction of immune cells to sites of pathology. This process enhances the sensitivity and specificity of imaging infections and inflammatory processes, making it a valuable technique in nuclear medicine.

In contrast, other options listed have different clinical applications. For instance, MDP (methylene diphosphonate) is typically used for assessing bone metabolism and detecting bone pathology rather than directly imaging infections or inflammation. Sestamibi is primarily utilized in evaluating cardiac function and myocardial perfusion, while EDTMP (ethylenediaminetetramethylene phosphonic acid) is not associated with thyroid imaging but is more relevant for certain bone procedures. These distinctions highlight the specialized role that Tc-99m HMPAO plays in imaging