Which of the following tracers may be used to confirm brain death?

The use of Tc99m-Exametazime, also known as Tc99m-HMPAO, is particularly pertinent in the context of confirming brain death due to its function as a radiotracer that assesses regional cerebral blood flow. In brain death, a significant decrease or absence of cerebral perfusion is expected. Tc99m-Exametazime distributes in brain tissue based on regional blood flow; therefore, during a scan, if there is no uptake seen in the cerebral hemispheres but activity is present in the brainstem or heart, it supports the diagnosis of brain death.

In contrast, the other tracers listed have different specific applications but are not utilized for confirming brain death. For instance, Tc-99m MDP (methylene diphosphonate) is primarily used in bone scans to detect bone diseases or metastatic disease, and therefore does not provide information on cerebral blood flow. Similarly, Tc99m-Sulfur Colloid is mostly used for liver, spleen, and bone marrow imaging, while Tc99m-PMT (positron emission tomography) may refer to systems that are not directly applicable for assessing cerebral perfusion in the same way. Thus, their roles are distinct, and they lack the specific functionality needed