Single photon emission computed tomography (SPECT) was performed in conjunction with 99mTc-macroaggregated albumin (Tc-MAA) hepatic arterial perfusion scintigraphy, and Tc-MAA activity was measured quantitatively. Three patients with colorectal liver metastasis were examined. In the first patient, the ratio of radioactivity in the area of the tumor was 3 times that in the surrounding liver. In the second patient, the right hepatic artery was ligated and Tc-MAA was injected into the left hepatic artery. Radioactivity in the right lobe was as much as in the left lobe. In the third patient, the left hepatic artery was ligated and Tc-MAA was injected into the right hepatic artery. Radioactivity was higher in the left lobe than in the right lobe. Previous reports suggested that Tc-MAA distribution accurately reflects the drug distribution injected into a regional blood supply. SPECT is useful in quantitative evaluation of Tc-MAA distribution.