Comparison of the efficiencies of technecium-99m (TC-99M) and galyum-68 (GA-68) labelled radiopharmaceuticals used for renal imaging purposes

PET and SPECT has an obvious diagnostic advantage over anatomical techniques such as classical BT and MR in determining biochemical changes which mainly occurs before anatomical changes. Most powerful sides of PET are precision, unlimited penetration depth and ability to gain quantitative data. the technique is relatively expensive and when compared to MR, spatial resolution is limited, but imaging agents types are usable to bind specific molecular targets that's why the technique is highly flexible. PET scans has more counting rate so it produces more images with less noise. In addition, PET allows for attenuation correction not possible with SPECT imaging and provides quantitative data. Unlike radiological imaging modalities, both PET and SPECT require small amounts of imaging agents (nanogram to milligram range). Both PET and SPECT are used for the imaging of a wide range of biological processes and disease states for clinical and research purposes. Kidney imaging provides significant functional data to evaluate the treatment and diagnosis for various kidney diseases using the Nuclear Medicine imaging techniques. Physiologically stable metal chelates such as EDTA, DTPA are disposed by glomerular filtration and are labeled with various radioisotopes to evaluate glomerular filtration rate. Based on this information, EDTA and DTPA were radiolabeled with Ga-68 and Tc-99m for Renal imaging in our study. Then, the labeled compounds quality control have been tested by RTLC and UHPLC to determine their radiochemical purity and optimum labeling conditions. The stability of the labeled compounds has been determined using an in vitro stability test and these compounds have been shown to be clinically suitable for use according to the pharmacopeia recommended limits (>95%). Tc-99m labeled EDTA and DTPA and Ga-68 labeled EDTA and DTPA were injected i.v. from the tail veins of mice. Static and dynamic images of the mice were taken. In red blood cell binding studies, Ga-68 labeled compounds were found to bind to red blood cell in low amounts, and as a result of in vivo PET imaging studies, Ga-68 labeled compounds were found to have high renal uptake.