Evaluating dose-response of cataract induction in radiotherapy of head and neck cancers patients

Background: Head and neck cancers are currently the most common types of cancers. 3D-conformal radiation therapy is the most common dose delivery technique for head and neck cancers. Eye Lens is a radio sensitive structure and cataract formation as a visual disorder associated with exposure to ionizing radiation which is documented. Objective: Determining the radiation dose to eye lens during head and neck radiography and estimating the probability of cataract induction are essential. Material and Methods: This experimental study was performed on 14 patients with head and neck cancers through experimental study analysis. The maximum opacity of the eyes lens were measured by pentacam� before radiation therapy. CT data of patients were transmitted to Isogray treatment planning Software, and dose calculations for each patient was performed. At the end of radiation treatment, 3 and 6 months after radiotherapy, the eye lens opacity of the patients was assessed. Results: Overall, 28 lenses were studied. Statistical one sample K-S test proved normality of obtained data. Using repeated measures test, the relation before and 3 months after radiotherapy, as well as the relationship before and 6 months after radiotherapy proved a significant relationship. Conclusion: The opacity caused by radiation in eyes is a non-statistical and linear-quadratic response curve with no threshold. This opacity can also appear within 3 months after completion of radiation therapy. © 2021, Shriaz University of Medical Sciences. All rights reserved

Cancer-selective, single agent chemoradiosensitising gold nanoparticles

Two nanometre gold nanoparticles (AuNPs), bearing sugar moieties and/or thiol-polyethylene glycol-amine (PEG-amine), were synthesised and evaluated for their in vitro toxicity and ability to radiosensitise cells with 220 kV and 6 MV X-rays, using four cell lines representing normal and cancerous skin and breast tissues. Acute 3 h exposure of cells to AuNPs, bearing PEG-amine only or a 50:50 ratio of alpha-galactose derivative and PEG-amine resulted in selective uptake and toxicity towards cancer cells at unprecedentedly low nanomolar concentrations. Chemotoxicity was prevented by co-administration of N-acetyl cysteine antioxidant, or partially prevented by the caspase inhibitor Z-VAD-FMK. In addition to their intrinsic cancer-selective chemotoxicity, these AuNPs acted as radiosensitisers in combination with 220 kV or 6 MV X-rays. The ability of AuNPs bearing simple ligands to act as cancer-selective chemoradiosensitisers at low concentrations is a novel discovery that holds great promise in developing low-cost cancer nanotherapeutics

An Investigation to Determine an Optimum Protective Garment Material in Nuclear Medicine

Aim: The aim of this study is to find an optimum material to protect garment for protection against 99Tcm radionuclide. Materials and Methods: Monte Carlo simulation code was applied to investigate radiation attenuation of 13 shielding materials including: Ba, gray Sn, white Sn, Sb, Bi, Bi2O3, BaSO4, Sn/W, Sb/W, Pb and W with thicknesses of 0.5 and 1 mm to determine an optimum protective garment material in nuclear medicine against 99Tcm. Furthermore, the dose enhancement on the staff body was investigated for shielding materials such as tungsten and lead. Results: The findings of the simulations show that the maximum and minimum attenuation obtained with thicknesses of 1 mm W and 1 mm BaSO4 were 96.46% and 14.2%, respectively. The results also demonstrate that tungsten does not cause any dose enhancement on staff body but this is not true for lead. Tungsten provides the highest radiation attenuation without dose enhancement on the body of staff. Conclusion: Among materials evaluated, tungsten is the optimum material and it can be applied for the design of protective garment for nuclear medicine staff against 99Tcm