A simple preparation and evaluation of 99mTc-Dowex 1 resin: Lungs perfusion imaging agent

1474 Objectives Pulmonary embolism is a common potentially fatal condition, for which the correct diagnosis and treatment arehighly effective. The use of 99mTc-macroggregated albumin for lung perfusion imaging is well established in nuclear medicine. However, there have been safety concerns over the use of blood-derived products because of potential contamination by infective agents, for example, Variant Creutzfeldt Jakob Disease. Methods Two milliliter of Na99mTcO4 (5.4 GBq) was added to 10mg Dowex 1 anion exchange resin 1x8, 200-400mesh, equilibrated in saline. The mixture was vortex mixed for 1min and centrifuged to separate the resin from the solution. The resin was washed repeatedly with saline (3 times). Finally the radiolabeled resin dispersed in saline was used for radiochemical and biological studies. Stability of 99mTc-Dowex 1 was studied in saline, rat plasma and human plasma at various intervals. Imaging of a rabbit with 99mTc-Dowex 1 (185 MBq, 2000 particles) was performed with a γ-camera at various intervals. Results A good radiolabeling efficiency ( 90-95%) was obtained. 99m-Dowex 1 retained its radiochemical purity in saline, rat plasma and human plasma upto 90% even at 5hr. The dynamic images showed that >95% of 99mTc-Dowex 1 appeared promptly in the lungs and remained constant for at least 20 min. Conclusions 99mTc-Dowex 1 labeled with a high radiochemical purity and radiochemical stability showed a high accumulation in the lungs. It has good potential for use as a perfusion imaging agent in lung scans