Search

This research aimed to determine the dose of radiation received in cancer therapy for each decay of Gadolinium atomic nuclei with isotope 157 (157Gd) in Gadolinium Neutron Capture Therapy using the SHIELD-HIT12A program. Knowing the amount of dose given to cancer tissue should aid in minimizing the damage that could occur in the healthy tissue around the cancer tissue, effectively killing only the cancer cells. The simulation employed in this research used the SHIELD-HIT12A program by providing input on beam.dat, mat.dat, detect.dat, and geo.dat files. The output data from the program comprised the value of recoil energy lost (energy absorbed into the target materials) for each of the 157Gd atomic nuclei, which was then processed by the dose determination equation to determine the dose given by the 157Gd nucleus to soft tissue. Based on the results, the amount of the dose given by each atomic nucleus 157Gd to soft tissue was 5.44 × 1011 Gy/decay.

The purpose of this study was to determine the in vitro and in vivo doses of boron neutron capture cancer therapy (BNCT) using the SHIELD-HIT12A program. To be able to determine the recoil energy, the research was conducted using the Monte Carlo method. Running data obtained the value of ionization activity and recoil lost. The results showed that in vitro and in vivo doses of BNCT for soft tissue irradiation had a value of 0.312 × 10-2 Sv, which is safe and does not harm healthy body tissue around the cancer cells because it is below the threshold of 1.5 Rem or 15 × 10-3 Sv, in accordance with the provisions of the upper value permitted by the International Commission on Radiation Protection in 1966. While the comparative targets are water, the optimal target absorption dose was obtained at concentrations of 3.232 × 10-3 Gy. The dose of carbon equivalent in water with the type of thermal neutron radiation was 16.16 × 10-3 Sv; this dose is classified as unsafe.

The Monte Carlo particle transport code SHIELD-HIT12A is designed to simulate therapeutic beams for cancer radiotherapy with fast ions. SHIELD-HIT12A allows creation of antiproton beam kernels for the treatment planning system TRiP98, but first it must be benchmarked against experimental data. An experimental depth dose curve obtained by the AD-4/ACE collaboration was compared with an earlier version of SHIELD-HIT, but since then inelastic annihilation cross sections for antiprotons have been updated and a more detailed geometric model of the AD-4/ACE experiment was applied. Furthermore, the Fermi–Teller Z -law, which is implemented by default in SHIELD-HIT12A has been shown not to be a good approximation for the capture probability of negative projectiles by nuclei. We investigate other theories which have been developed, and give a better agreement with experimental findings. The consequence of these updates is tested by comparing simulated data with the antiproton depth dose curve in water. It is found that the implementation of these new capture probabilities results in an overestimation of the depth dose curve in the Bragg peak. This can be mitigated by scaling the antiproton collision cross sections, which restores the agreement, but some small deviations still remain. Best agreement is achieved by using the most recent antiproton collision cross sections and the Fermi–Teller Z -law, even if experimental data conclude that the Z -law is inadequately describing annihilation on compounds. We conclude that more experimental cross section data are needed in the lower energy range in order to resolve this contradiction, ideally combined with more rigorous models for annihilation on compounds. [ABSTRACT FROM AUTHOR]