Portal vein embolization (PVE) has been carried out for various hepatobiliary malignancies such as hepatocellular carcinoma (HCC). 1-9 PVE for HCC was first introduced in 1986 by the Osaka City University group in Japan. 1 PVE is mainly done to obtain a larger future liver remnant (FLR) to expand the safety zone of liver resection. Even for HCC patients with fibrous livers, liver resectability is increased after PVE without increasing morbidity and mortality. 3,5,7 Previous studies have assessed liver resectability based on liver function and FLR volume using computed tomography (CT)volumetry. [8][9][10][11] Nowadays, functional liver volumetry using 99m Tc-galactosyl human serum albumin scintigraphy single-photon emission CT is used to assess partial liver function after PVE. 12-16 PVE can provide a larger functional volume of the FLR as compared to those before PVE. Additionally, the functional volume ratio after PVE has