Why are the legs wrapped with elastic bandages before performing a venogram with Tc99-MAA?

Wrapping the legs with elastic bandages before performing a venogram with Tc99-MAA serves the purpose of suppressing superficial circulation. By compressing the superficial veins, the bandaging helps redirect blood flow into the deeper venous system. This is important for nuclear medicine procedures involving radiopharmaceuticals, such as Tc99-MAA, because it enhances the accuracy of the imaging results by minimizing the interference from the superficial structures.

Suppressing superficial circulation allows for a clearer imaging of the venous structures and better distribution characteristics of the radiotracer, ensuring that the diagnostic goal of the venogram is met. Effective imaging is crucial for evaluating conditions such as venous obstruction or other vascular abnormalities, making this technique critical in nuclear medicine protocols.

This approach contrasts with reasons like preventing blood clots, which is not the primary purpose of elastic bandaging in this context, nor is it aimed at enhancing patient comfort.