The number of PET/CT tests for diagnosing and treating tumors are increasing every year, and thus it is considered necessary to compare PET/CT images among medical institutions or among different PET/CT systems within the same medical institution. We present to get the variation of standardized uptake values (SUV) among PET/CT systems, to derive an SUV calibration table that enables quantitative comparison of PET/CT systems, and to test the usefulness of the calibration table through comparing patient's SUV with the SUV calibration table. The correlation coefficients that inter-compared the calibration constants of normal patients and the calibration constants of the mean standardized uptake value with the calibration constants of the standardized uptake value of phantom are 0.88938 (P<0.0001).