The purpose of the study was to identify how isotope and magnetic resonance imaging (MRI) contrast media impact on noise to computed tomography (CT) examination. For the study, divide the phantoms to two groups: 1) saline, saline + different kinds of contrast agent without To obtain an image, we used CT scanner. With an obtained image, we set the 1 cm 2 region of interest in the middle of bottle to measure the noise and CT number. As a result, there was no difference in CT number before and after inserting 99m Tc into all contrast media including Normal Saline. However, when it comes to Noise, there was a difference before and after inserting 99m Tc into every contrast media except MRI contrast media such as Primovist ® and Gadovist ® .