In Tc bicisate (ECD), which organ receives the highest radiation dose?

• A. Heart
• B. Liver
• C. Kidneys and bladder
• D. Brain

Answer: (C)

In the context of Tc bicisate (ECD), the kidneys and bladder receive the highest radiation dose due to the pharmacokinetics of the radiopharmaceutical. Tc bicisate is primarily used for brain imaging in nuclear medicine, but it is also significantly excreted through the renal system. This means that after administration, a considerable amount of the radioactivity localizes in the kidneys as they filter the blood, and subsequently in the bladder as the urine accumulates.

The concentration of the radiopharmaceutical in these organs is a result of both their function in excretion and the distribution characteristics of ECD. While the brain is the primary target for imaging with Tc bicisate, the rapid clearance through the kidneys highlights their significant exposure to radiation. Therefore, when looking at organ doses, the kidneys and bladder indeed receive the highest dose due to their role in processing and eliminating this radiopharmaceutical from the body.