Question

For a patient with intermittent GI bleeding, the best RP to locate the bleed is:

a. Tc99m SC
b. Tc99m denatured RBCs
c. Tc99m WBCs
d. Tc99m DTPA
e. none of the above

Answer 1

Tc99m labeled red blood cells (denatured RBCs) are the best choice to locate intermittent GI bleeding due to their ability to pool at bleeding sites and be detected externally.

Step-by-step explanation:

For a patient with intermittent gastrointestinal (GI) bleeding, the best radiopharmaceutical (RP) to locate the bleed is Tc99m labeled red blood cells (denatured RBCs). Technetium-99m (Tc-99m) is used in numerous diagnostic procedures because it emits a 0.142-MeV gamma ray that can be easily detected externally and has a convenient 6-hour half-life. It can be attached to many compounds for imaging different body systems. In the case of GI bleeding, labeled red blood cells enable the detection of active bleeding sites within the GI tract due to their ability to circulate within the bloodstream and pool at the site of bleeding, which can then be identified by external detectors.