Influence of Iodinated Contrast Media and Paramagnetic Contrast Media on Changes in Uptake Counts of Tc-99m

Abstract

The purpose of this study is to figure out how uptake counts of technetium (Tc-99m) among radioisotopes in the human body are affected if computed tomography (CT), magnetic resonance imaging (MRI) and isotope examination are performed consecutively. Tc-99m isotope material, iodinated contrast media for CT and paramagnetic contrast media for magnetic resonance (MR) were used as experimental materials. First, Tc-99m was added to 4 cc normal saline in a test tube. Then, 2 cc of CT contrast media such as Iopamidol and Dotarem were diluted with 2 cc normal saline, and 2cc of IVIRI contrast media such as Primovist and Gadovist were diluted with 2 cc normal saline. Each distributed contrast media was a total of 4 cc and included 10m Ci of 99"Tc. A gamma camera, a LEHR (Low energy high resolution) collimator and a pin-hole coffimator were used for image acquisition. Image acquisition was repeated a total of 6 times and 120 frames were obtained and uptake counts of Tc-99m were measured (from this procedure). In this study, as a result of measuring the uptake counts of Tc-99m using the LEHR collimator, the uptake counts were less measured in all contrast media than normal saline as a reference. In particular, the lowest uptake counts were measured when Gadovist, contrast media for MIRE, was used. However, the result of measuring the uptake counts of Tc-99m using the pin-hole collimator showed higher uptake counts in all contrast media, except for Iopamidol, than normal saline as a reference. The highest uptake counts were measured particularly when Primovist, contrast media for MIRE, was used. In performing the gamma camera examination using contrast media and Tc-99m, it is considered significant to check the changes in the uptake counts to improve various diagnosis values.