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 ^99mTc administration; 2) ^99mTc administration: saline, saline + different kinds of contrast agent with ^99mTc administration. CT contrast agent was used for Iopamidol^® and Dotarem. And MRI contrast agent was used for Primovist^® and Gadovist^®. To obtain an image, we used CT scanner. With an obtained image, we set the 1 cm2 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 ^99mTc into all contrast media including Normal Saline. However, when it comes to Noise, there was a difference before and after inserting ^99mTc into every contrast media except MRI contrast media such as Primovist^® and Gadovist^®.