PURPOSE The purpose of this study was to evaluate the accuracy for quantitative predictor of hepatic functional reserve using planar and single photon emission computed tomography (SPECT) images. METHODS We acquired planar and SPECT images of the myocardial torso phantom and calculated LHL (uptake ratio of the liver to the liver plus heart). Planar images were used with and without scatter correction. Myocardial torso phantom was simulated radioactivity distribution of normal liver function and poor liver function. This study compared the LHLplanar (calculated by planar images) and the LHLSPECT (calculated by SPECT images) with the true value (calculated by radioactivity concentration in the phantom) and evaluated the error rate. RESULTS Error rate of LHLSPECT was improved compared with the LHLplanar. The error rate of LHLplanar (with scatter correction) was increased in the poor liver function than in the normal liver function. CONCLUSIONS The SPECT images have higher advantage to predict the liver function than the planar images.