Hepatic arterial infusion pumps (HAIPs) are used for the administration of targeted liver-directed chemotherapy in patients with hepatic metastases from colorectal cancer and intrahepatic cholangiocarcinoma. After HAIP placement, but prior to initiation of liver-directed chemotherapy, imaging is performed to ensure that agents injected into the pump reach the liver parenchyma, and only the liver parenchyma, to avoid damage to other organs. Distribution of chemotherapy can be simulated by the administration of a radiopharmaceutical that is also injected into the HAIP and then gets trapped in the liver. This is performed by the administration of 99mTc-macroaggregated albumin (99mTc-MAA) into the HAIP. The particles of this radiopharmaceutical are larger in diameter than capillaries (range, 10–90 μm; mean, 30–50 μm) and cannot permeate the intrahepatic capillary beds. Therefore, these particles become trapped (for some time, before their breakdown into smaller particles), providing sufficient time for imaging. 99mTc-MAA, therefore, serves as a surrogate marker for chemotherapy delivery. Images of the 99mTc-MAA distribution are acquired with single photon emission computed tomography/computed tomography (SPECT/CT) cameras. This chapter discusses the technique of radiotracer administration, imaging procedure, as well as normal and abnormal findings on SPECT/CT in this setting.