PET/CT is a machine for imaging in vivo functions or metabolic activities after the administration of radiopharmaceuticals labeled with radioisotope emitting positrons in the body. Recently the number of PET/CT installed in Korean medical institutions is increasing rapidly. In response, the number of PET/CT tests to be used in the diagnosis and treatment of tumors is also increasing every year, and this is increasing the necessity for developing the methods of PET/CT performance evaluation and quality control. Among the test items for the performance evaluation and quality control of PET/CT suggested in NU 2-2007, this study examined spatial resolution test, sensitivity test, image quality, attenuation accuracy & scatter correction test, scatter fraction, count losses and randoms test and accuracy( correction for count losses and randoms).