Enhancement of Nanoparticles for Contrast Agents and Radiation Dose Distribution in Breast Cancer Using Monte Carlo Simulation

Abstract

Screening mammography is a very common procedure for early breast cancer diagnosis. The attenuation of x-ray similarities between breast cancer tissue and adipose/glandular tissue makes the diagnosis challenging. Many researchers have been still working to developing nanoparticles (NPs) for contrast agents. This study used Monte Carlo simulation (MCNP5), to simulate spherical tumors 1, 3 and 5 mm in diameter. Different concentrations of Gold (Au) NPs, Bismuth Oxide (Bi2O3) NPs and Iodine contrast agents (Iohexol) was used in simulation to determine the minimum concentration of these materials necessary to detect small size tumors. The criterion for detectability was a differential signal to noise ratio larger than 3. The results indicate that for a 2.8 mm tumor a minimum Bi2O3NPs and Au NPs concentration of 5% is required. A minimum concentration 3% of Bi2O3 NPs and Au NPs is required for detection of tumor diameter of 3.5 mm. For iodine contrast agent (Iohexol), a 5 mm tumor diameter is not detectable even at 5 % concentration. Minimum contrast enhancement has been achieved at minimum contrast agent concentrations in tissues without any toxic effects. The stopping power and energy range for proton was calculated by two numerical methods and other two simulation techniques. The values of stopping power have been calculated in the range of energies between 1 MeV to 100 MeV in breast tissue. The criterion of the total stopping power was compare with PSTRA and SRIM 2013 simulation programmes the result is quite agree with numerical results. The range determined numerically by Continuous Slowing Down Approximation (CSDA). The result is agrees with the PSTAR (NIST) data and SRIM 2013 within different percentage less than 3 %. The quantitative comparison done with IV other results showed that it has an overall good agreement within different percentage less than 10 %. The data will be useful for applications in radiobiology and researchers. The equation of Bethe-Bloch is meanly used to understand how to calculate the stopping power of proton, but not for radiative energy loss. Bethe-Bloch equation has been modifying and generalizing, for water and breast tissue to calculate mass stopping power of protons in specific energy range. The effective of atomic number Zeff and mean atomic mass Aavg of target were also varied with the stopping power. The result is in a good agreement with the previous work for all energy range values from 1 MeV up to 100 MeV. The variation in 𝑍𝑒𝑓𝑓, over the 1-100 MeV energy range considered, results revealed that breast tissue could be considered as water equivalent for interaction of various fundamental nanoparticles.