Determination of energy absorption and exposure buildup factors by using G-P fitting approximation for radioprotective agents

Enhancement of Gamma-ray Shielding Properties in Cobalt-Doped Heavy Metal Borate Glasses: The Role of Lanthanum Oxide Reinforcement

The direct influence of La³⁺ ions on the gamma-ray shielding properties of cobalt-doped heavy metal borate glasses with the chemical formula 0.3CoO-(80-x)B₂O₃-19.7PbO-xLa₂O₃: x = 0, 0.5, 1, 1.5, and 2 mol% was examined herein. Several significant radiation shielding parameters were evaluated. The glass density was increased from 3.11 to 3.36 g/cm³ with increasing La³⁺ ion content from 0 to 2 mol%. The S5 glass sample, which contained the highest concentration of La³⁺ ions (2 mol%), had the maximum linear (μ) and mass (μ_m) attenuation coefficients for all photon energies entering, while the S1 glass sample free of La³⁺ ions possessed the minimum values of μ and μ_m. Both the half value layer (T_1/2) and tenth value layer (TVL) of all investigated glasses showed a similar trend of (T_1/2, TVL)_S1 > (T_1/2, TVL)_S2 > (T_1/2, TVL)_S3 > (T_1/2, TVL)_S4 > (T_1/2, TVL)_S5. Our results revealed that the S5 sample had the highest effective atomic number (Z_eff) values over the whole range of gamma-ray energy. S5 had the lowest exposure (EBF) and energy absorption (EABF) build-up factor values across the whole photon energy and penetration depth range. Our findings give a strong indication of the S5 sample’s superior gamma-ray shielding characteristics due to the highest contribution of lanthanum oxide.

Photon interaction performance of various contrast agents: Theoretical and simulation results

In this study, total mass attenuation coefficient (μ/ρ) values in the energy range from 60 keV to 15 MeV for some contrast agents (Iopamidol, Metrizamide, Iohexol, Ioxaglic acid, Iopromide, Ioversol and Iopentol) were determined with the WinXCOM computer program and GEANT4 computer simulation code. Linear attenuation coefficients (μ), half value layers (HVL), tenth value layers (TVL), mean free paths (mfp), effective atomic numbers (Z_Eff) and effective electron densities (N_Eff) in the aforementioned energy range were obtained with the help of the calculated total mass attenuation coefficients. Energy absorption build-up factors (EABF) and exposure build-up factors (EBF) for contrast agents were calculated using the five-parameter geometric progression (G-P) fitting method in the energy region of 0.015 MeV ≤ E ≤ 15 MeV for different penetration depths up to 40 mfp with the help of the equivalent atomic numbers (Z_eqv). Kerma relative to air values were investigated in the energy region 0.001 MeV ≤ E ≤ 20 MeV. It has been observed that Ioxaglic acid is a good radiation absorber according to the other studied contrast agents. The present results may contribute to various application areas of radiation research.

Medicinal Thiols: Current Status and New Perspectives

The thiol (-SH) functional group is found in a number of drug compounds and confers a unique combination of useful properties. Thiol-containing drugs can reduce radicals and other toxic electrophiles, restore cellular thiol pools, and form stable complexes with heavy metals such as lead, arsenic, and copper. Thus, thiols can treat a variety of conditions by serving as radical scavengers, GSH prodrugs, or metal chelators. Many of the compounds discussed here have been in use for decades, yet continued exploration of their properties has yielded new understanding in recent years, which can be used to optimize their clinical application and provide insights into the development of new treatments. The purpose of this narrative review is to highlight the biochemistry of currently used thiol drugs within the context of developments reported in the last five years. More specifically, this review focuses on thiol drugs that represent the standard of care for their associated conditions, including N-acetylcysteine, 2,3-meso-dimercaptosuccinic acid, British anti-Lewisite, D-penicillamine, amifostine, and others. Reports of novel dosing regimens, delivery strategies, and clinical applications for these compounds were examined with an eye toward emerging approaches to address a wide range of medical conditions in the future.