In which organs does Tc HDP and Tc MDP normally distribute in the body?

• A. Liver and spleen
• B. Muscles and heart
• C. Bones, excreted through kidneys and bladder
• D. Brain and lungs

Answer: (C)

Technetium-99m labeled compounds like Hydroxyethylene Diphosphonate (HDP) and MDP (methylene diphosphonate) are specifically designed for bone imaging due to their preferential accumulation in skeletal tissue. These radiopharmaceuticals have a high affinity for osteoblastic activity, which means they concentrate in areas of bone growth or repair. This characteristic makes them particularly useful in diagnosing bone diseases, such as fractures, infections, and tumors.

Once these compounds are administered, they are distributed throughout the bones in the body, allowing for clear imaging of skeletal structures using gamma cameras. Following their uptake in the bones, the residual technetium is primarily excreted by the kidneys and eliminated from the body through the urinary tract. This pathway of distribution and excretion is a key factor in the utility of Tc HDP and Tc MDP in clinical settings, as it allows for precise imaging of bone-related issues.

In contrast, the other organs mentioned in the other options do not have a similar relationship with HDP and MDP. For example, while the liver and spleen are important organs in the body, they do not accumulate these radiopharmaceuticals in significant amounts. Likewise, muscles and the heart, as well as