Founded in 1999 under the bilateral U.S.-Russian Agreement on International Cooperation for Minimization of the Effects of Prolonged Radiation Exposure, the Human Radiobiological Tissue Repository (HRTR) at the Southern Urals Biophysics Institute aims to collect, store, annotate, and disburse biological materials from individuals occupationally exposed to ionizing radiation, to support scientific investigations of the effects of radiation exposure on human health. In compliance with international best practices guidelines, the RHTR has assembled a collection of over 100,000 biospecimens donated by workers of the Mayak Production Association, and by non-occupationally exposed persons living in the same city. Included in its biobanks are fully annotated autopsy tissues stored in formalin, formalin-fixed paraffin-embedded tissue blocks, microscope slides, frozen surgical tissues, whole blood and blood components, and genomic DNA from parental-offspring triads. The biorepository's database contains information on radiation dose characteristics, occupational history, non-radiation risk factors, detailed medical history, and social and demographic characteristics of each donor. This comprehensive approach has resulted in a unique resource that has supported both molecular and non-molecular studies of radiation health effects.

Paediatric patients are particularly sensitive to ionizing radiation, and accurate surface dose estimation is crucial in diagnostic X-ray imaging. Standard homogeneous phantoms inadequately reproduce tissue heterogeneity, leading to errors in backscatter evaluation. This study aimed to characterize backscatter factors (BSFs) in a heterogeneous, tissue-equivalent paediatric head phantom under conventional radiography conditions. An in-house epoxy-based heterogeneous phantom was fabricated with five inserts simulating bone, brain, cerebrospinal fluid, eye lens and air cavities. Entrance surface dose (ESD) and BSF measurements were performed using an ionization chamber and a Fujifilm digital X-ray system (40-150 kVp, field sizes: 10 × 10, 20 × 20, 25 × 25cm²). Additional aluminium filtrations of 2.5mm and 3.0mm were applied to evaluate beam hardening effects. Measured ESD increased from 0.82 mGy at 40 kVp to 18.93 mGy at 150 kVp (no filtration, 25 × 25cm²). Applying 3.0mm Al filtration reduced ESD by up to 57% at 60 kVp. Experimental BSFs ranged from 1.1 to 2.1, increasing with tube potential and reaching a maximum under small field size and hardened beam (120 kVp, 10 × 10cm², 3.0mm Al), reflecting enhanced cumulative backscatter energy from heterogeneous tissue interfaces. Compared with IAEA TRS-457 reference data, the heterogeneous phantom yielded higher BSFs than PMMA or water for 10 × 10cm² fields, demonstrating enhanced scatter from realistic tissue interfaces, while lower BSFs were observed for larger fields. The study confirms that homogeneous phantoms may underestimate paediatric backscatter under specific conditions, while heterogeneous phantoms provide more representative dosimetric references, improving BSF estimation and dose optimization.

Radiation-related dental caries (RRC) is a rapidly progressing and treatment-resistant condition commonly observed after head and neck radiotherapy. It has traditionally been attributed to radiation-induced salivary gland dysfunction; however, RRC often develops even when appropriate oral care is provided, including fluoride application and regular hygiene practices. This clinical inconsistency suggests that salivary dysfunction alone cannot fully explain the onset and severity of RRC. The direct physicochemical effects of radiation on the organic and inorganic components of dental hard tissues remain poorly understood. In this study, extracted human third molars were subjected to a clinical IMRT protocol, using either a single high dose (20Gy × 1) or a fractionated regimen (2Gy/day × 35, total 70Gy). We then evaluated radiation-induced changes in tooth structure by measuring Vickers microhardness, acid resistance (calcium elution), collagen degradation (autofluorescence), and internal dentin pH. Radiation exposure significantly altered enamel hardness: it increased after 20Gy but decreased following 70Gy. Calcium release increased in crown enamel (70Gy) and root dentin (20Gy), while decreasing in crown dentin (20Gy). Autofluorescence imaging showed a significant reduction in dentinal collagen after fractionated exposure. Both groups exhibited an alkaline shift in dentin pH, more pronounced in the single-dose group. These findings provide physicochemical evidence for a non-salivary mechanism contributing to RRC. To effectively prevent RRC, additional strategies to reduce direct radiation damage to dental tissues may be necessary alongside conventional salivary-focused approaches.

The rapid evolution of cancer treatment modalities has positioned proton therapy as a highly effective approach for targeting specific tumours. Proton therapy takes advantage of the Bragg peak phenomenon to deliver a concentrated dose to the tumour while minimizing exposure to surrounding healthy tissues. This feature has spurred interest in further enhancing proton therapy through the integration of advanced technologies, such as image-guided proton therapy and nanoparticle (NP) application. The incorporation of NPs into tumour tissues has emerged as a promising strategy to enhance the delivered dose in radiation therapy. This study investigates the dose enhancement factor (DEF) resulting from the presence of various NPs, when irradiated by a spread-out Bragg peak of a 120MeV proton beam. Additionally, the magnetic dose enhancement factor (MDEF) under transverse magnetic fields of 3 T and 7 T is examined using the Geant4 simulation toolkit. The findings clarify the NP-mediated dose enhancement in proton therapy, particularly in the context of MRI-guided treatments. The highest DEF occurs within NPs (e.g., 1,341% for Ir), while the surrounding tissue exhibits negligible enhancement (< 10% up to a radial distance of 500nm). The results indicate that magnetic fields up to 7 T do not significantly alter dose distributions around NPs. While validating the compatibility of NP-enhanced proton therapy with MRI guidance, this work provides a comparison of metallic (Au, Ir, Gd, and SPION) and non-metallic (B, C) NPs, establishing a foundation for clinical NP selection and future radiobiology studies.

In 1994, the United States and the Russian Federation signed an agreement to cooperate in research on radiation effects, establishing the Joint Coordinating Committee for Radiation Effects Research (JCCRER). Over the past 30 years, the JCCRER has focused on understanding the health effects of chronic radiation exposure, particularly in the Mayak Production Association facilities and surrounding areas. The research has led to significant advancements in radiation protection, with projects categorized into public exposures and effects, and worker exposures and effects. Key projects include dose reconstruction, cancer risk estimation, and the development of dosimetry models. The collaboration has resulted in numerous scientific publications and has set a precedent for future international scientific partnerships. This article summarizes the intent and results of each of the projects performed under the JCCRER over the past 3 decades.

The choice of a CT-RED calibration curve directly influences the accuracy of dose calculation in treatment planning systems (TPS), depending on treatment technique, anatomical site and calculation algorithm. This study aimed to evaluate the impact of variations in CT-RED calibration curves due to different tube voltages (kVp) on breast cancer treatment plans as a function of calculation algorithm. CT-RED calibration curves were generated using a CIRS M062 phantom scanned with a 16-slice HITACHI Supria CT scanner at 80, 100, 120, and 140 kVp. These curves were applied to treatment plans for left breast cancer using the Collapsed Cone (CC) and X-ray Voxel-based Monte Carlo (XVMC++) algorithms in MONACO TPS (v6.6.2). Dose-volume histograms and dose statistics were analyzed to assess dose metrics for planned target volumes (PTV) and organs at risk (OAR). Monte Carlo-based dose calculations showed significant sensitivity to kVp settings, while CC results exhibited clinically negligible effects, underscoring that the impact of kVp on dose calculation depends on the algorithm used. Thus, to ensure accurate dose calculations, it is important to adjust calibration curves for each kVp setting when using Monte Carlo algorithms. Furthermore, it is recommended to include this adjustment into the CC algorithm, despite the minimal differences observed, in order to ensure consistency with the ALARA (As Low As Reasonably Achievable) principle.

This study investigates the radiation shielding performance of lead borosilicate waste glass when incorporated as an additive into cement-bitumen composites. The utilization of lead borosilicate glass, a byproduct of industrial processes, offers a dual advantage: it enhances the gamma-ray attenuation capacity of the composite achieving a mass attenuation coefficient of 7.85 × 10⁻² cm²/g and simultaneously contributes to the sustainable management of radioactive waste by improving the compressive strength to 32.9MPa. Cement-bitumen mixtures were prepared with varying concentrations of the waste glass and evaluated through both experimental measurements and theoretical modeling. The linear attenuation coefficients demonstrated a marked improvement in shielding efficiency with increasing lead content. Computational tools, including XCOM and Geant4, were employed to simulate photon interactions and validate the experimental findings. The simulation results were in strong agreement with experimental data, confirming the enhanced attenuation properties at higher glass concentrations. These findings suggest that lead borosilicate waste glass is a promising additive for improving the gamma radiation shielding properties of cement-bitumen matrices, with potential applications in nuclear waste immobilization and radiation protection. Furthermore, the approach promotes sustainable recycling of industrial waste, aligning with environmental conservation goals. Further research is recommended to optimize glass loading and assess the long-term durability and structural performance under diverse environmental conditions.