Radiation, Volume 5, Issue 3 (September 2025) – 3 articles

The Klein–Nishina formula is used to calculate and investigate the electronic cross-section, atomic cross-section, and Compton mass attenuation coefficients for the human blood, breasts, eye lens, ovaries, and testis, using X-rays in the 0.1–20 MeV energy range. The effects of radiation energy, tissue effective charge number, tissue density, and tissue electronic density on these parameters were studied. The results show that the electronic cross-section and atomic cross-section decrease with increasing radiation energy. These parameters are found to be linearly increasing when the density and electron density of a tissue increase. This increase is more rapid with a bigger slope when the electron density increases as compared to the density of each tissue. A complex relationship between these coefficients and the effective charge number Z_eff of tissues is observed because Z_eff changes with the energy and linear attenuation coefficient of a tissue. The Compton mass attenuation coefficient is found to be dependent on the effective charge number to mass number ratio Z_eff/A_eff instead of just the effective charge number. This increase in the Compton mass attenuation coefficient with increasing Z_eff/A_eff is rapid for the lower values of Z_eff/A_eff. However, for a higher Z_eff/A_eff ratio, the increase is very slow and becomes almost constant for X-ray energies above 10 MeV. The calculated parameters are useful in determining radiation dose for the investigated tissues and their response to low and high-energy X-rays. The results and outcomes are also very useful in shielding and protecting tissues from the hazards of radiation. These parameters are also helpful in determining the scattered and optimum doses to improve image quality and treatment options in radiology and radiation therapy to offer the best care. Full article

Background: Delays in breast cancer treatment negatively affect prognosis and have increased over time. Data on waiting times in Switzerland are limited. Patients and Methods: This study analyzed cancer registry data from 2003 to 2005 (2628 patients) and 2015 to 2017 (421 patients) to evaluate waiting times for diagnosis, surgery, and radiotherapy; temporal trends; and survival in women with stage I–III invasive breast cancer treated with surgery without chemotherapy. Associations with demographic/clinical factors and overall survival (OS) were assessed using ANOVA, uni-/multivariable regression, Kaplan–Meier, and Cox regression. Results: From 2003 to 2005, mean intervals were biopsy-to-diagnosis 4.3 days, diagnosis-to-surgery 18.8 days, biopsy-to-surgery 26.8 days, and surgery-to-radiotherapy 56.7 days. Longer diagnosis-to-surgery times were associated with metropolitan areas, public hospitals, basic insurance, mastectomy, and older age (all p < 0.001). Radiotherapy delays were also longer in metropolitan areas and after mastectomy (p < 0.001). Between 2003–2005 and 2015–2017, diagnosis-to-surgery times rose in Eastern Switzerland (from 21.3 to 31.2 days), while radiotherapy timing remained stable. Five-year overall survival improved (from 76.7% to 88.4%), but was not significantly impacted by diagnosis-to-surgery intervals. Conclusions: Despite timely surgery in Switzerland (2003–2005), disparities existed, and time to surgery increased by 2015–2017. Reducing waiting times remains important despite no significant short-term OS impact. Full article

Background: We present the implementation of an in vivo dosimetry program that enhances treatment setups, ensuring high accuracy that is needed globally. This approach proves valuable in smaller departments by helping to detect and prevent errors. Evaluation studies have shown that in vivo dosimetry is a reliable method for assessing the overall accuracy of treatment delivery. Methods: Comprehensive development and validation of an in vivo dosimetry program using silicon diodes, ionization chambers, and calibrated electrometers for accurate radiation in dose measurements for treatments involving Co-60 or 6 MV X-ray beams. Results: The outcomes demonstrated that all diodes were dependable, with deviations of less than 1% (0.89 ± 0.10 cGy). Calibration curves were generated, showing dose variations of only 0.13% in the diode readings. The overall analysis revealed a mean deviation of up to 1%. Conclusions: These results provide a thorough assessment for patients’ treatment and facilitate timely interventions when needed, helping to ensure that dose variations stay within acceptable limits. Full article