The effect of contrast agents and Tc-99m radionuclide simultaneously to increase the dose in cancer therapy

Aim and Background: One of the methods of cancer treatment is the use of beta and alpha emitter radionuclides such as iodine-131 and radium -223. Gamma-radionuclides are not usually used for treatment due to high gamma-ray penetration and lower absorption in the tissue, and they are mostly diagnostic. In this study, a new method is proposed in which the feasibility of using 99mTcO-4 as a gamma-emitting radionuclide for the treatment of cancer by adding high-atomic substances such as iodine and gadolinium to increase the surface area of ​​photon absorption in the tissue and Finally, an increase in the absorbed dose of the tumor is investigated. Material and methods Radiopharmaceutical 99mTcO-4 was milked from a 99Mo/99mTc generator, and after injection, the mice were killed at different times and the percentage of injected dose per gram of each member was determined by direct counting of mice data. Then, by transforming the mice results into humans, the dose of internal radiation was calculated. In the next step, by introducing contrast agents (I, Gd) at different concentrations in the target organs, the rate of change in absorbed dose of organs was calculated using the MCNP simulation code. MCNP results show that the absorbed dose has increased in the presence of contrast agents (I, Gd) in the liver and lung, taking into account the human accumulation activity (derived from healthy mice). Dose enhancement factor was evaluated using contrast agents. The results showed that with increasing concentrations, the dose enhancement factor in the target region increases in the presence of contrast agent and the dose outside the target position decreases. As a consequence of the increased dose resulting from the presence of contrast agents, the diagnostic radionuclide 99mTc can be used as a radionuclide for treatment in future.