Which tracer can be used to assess the patency of ventriculoperitoneal shunts?

To assess the patency of ventriculoperitoneal shunts, 99mTc pertechnetate is the most appropriate tracer. This is due to its physical and chemical properties that allow it to be easily mobilized through a shunt system and detected using gamma cameras.

99mTc pertechnetate is water-soluble and can be effectively used for imaging in various compartments, making it suitable for evaluating the flow dynamics of shunts. When introduced into the ventricular system, if the shunt is patent, activity will be visualized in the peritoneal cavity on the imaging study. This capability facilitates the assessment of any obstructions or malfunctioning within the shunt pathway.

The other tracers mentioned do not provide the same level of effectiveness for this specific purpose as 99mTc pertechnetate does. For instance, 111 In chloride is primarily used in imaging specific tumors or infection sites due to its long half-life and different distribution characteristics. 99mTc MAA (macroaggregated albumin) is primarily utilized in lung perfusion studies, particularly for assessing pulmonary embolism, rather than shunt patency. 99mTc bicisate is a brain perfusion agent used for imaging cerebral blood flow