Final answer:
Technetium-99m (99mTc) is typically the radiopharmaceutical used for imaging prior to Y-90 radioembolization of malignant hepatic lesions, due to its helpful imaging properties and low radiation exposure.
Step-by-step explanation:
The radiopharmaceutical utilized for the work-up prior to Y-90 radioembolization of malignant hepatic lesions is typically technetium-99m (99mTc). This radioisotope is often used in many compounds for medical imaging due to its properties, such as emitting a single, identifiable gamma ray and having a short half-life of 6 hours, which minimizes radiation exposure to the patient. In the context of hepatic lesions, technetium-99m can be used to image the liver and identify damaged tissues, as it is preferentially absorbed by such areas. The emitted gamma rays from the radioisotope are then detected, which allows for the creation of an image that can show the size, shape, and position of liver tumors, providing valuable information for treatment planning in interventional radiology.