New radiotherapy techniques have been innovative in recent decades with the aim of maximizing the dose to tumor tissue and reducing the dose to healthy tissue. One of the modalities that has gained prominence, using low-energy beams, is intraoperative radiotherapy (IORT), as it is a method based on high radiation doses (10–20 Gy) administered to the tumor bed immediately after surgical excision. IORT can be achieved through treatment with low-energy X-ray beams with some devices available on the market. However, such devices provide little dosimetric information and lack a calibration protocol. According to the recently updated recommendations of the TRS 398 standard (2024), for the use of low-energy beams, the ideal is to use a parallel plate ionization chamber calibrated in terms of absorbed dose in water. Based on TRS 398, this work established a calibration protocol for parallel plate dosimeters in terms of absorbed dose in water at the Center for Ionizing Radiation Metrology (CEMRI) of the Institute for Energy and Nuclear Research (IPEN).

Pulmonary embolism (PE) is a life-threatening condition for which computed tomography pulmonary angiography (CTPA) is the standard diagnostic modality. However, conventional CTPA protocols require relatively high iodine contrast and radiation doses, raising concerns about renal injury and radiation exposure. In this study, we propose a deep learning-based framework for PE diagnosis under low-iodine and low-radiation CTPA conditions. The proposed two-stage framework integrates image enhancement and classification by jointly leveraging original low-exposure images and their super-resolved counterparts. We further construct and publicly release a low-iodine, low-radiation CTPA dataset developed in collaboration with a clinical institution to support reproducible research in safe imaging. Experimental results demonstrate that the proposed method substantially improves diagnostic performance compared with single-branch baselines, achieving an area under the ROC curve (AUC) of 0.928 while maintaining balanced sensitivity and specificity. These findings suggest that the proposed framework enables accurate and safer PE diagnosis under reduced contrast and radiation exposure, offering a practical solution for improving diagnostic safety in clinical CTPA imaging.

Computed tomography is acknowledged as the most widely used imaging technique in both adults and children. Although computed tomography offers valuable diagnostic information, it contributes to a high radiation dose and poses relatively high risks of stochastic effects to patients. Stochastic risks are of special concern in pediatric imaging since children are more vulnerable to effects of ionizing radiation than adults. Therefore, the justification of pediatric computed tomography examinations is of paramount importance to critically weigh the benefits of computed tomography against the individual detriment. This study evaluates the current radiological justification for pediatric computed tomography in Kenya and propose strategies to enhance justification. An extensive literature review on pediatric computed tomography justification was explored based on the international guidelines of ICRP and IAEA and individual publications. The foundation of the review focused on the 3 A's: awareness, appropriateness, and audits as tools to ensure proper justification. The recommendations and guidelines proposed in this study can guide in the implementation of the 3 A's in the country.

Osteosarcoma is a rare malignant bone tumor that is difficult to manage with traditional methods. The technique of delivering single fraction high-dose radiation directly to the bone, extracorporeal irradiation (ECI), minimizes radiation-induced damage to adjacent healthy tissues. Planning the ECI technique as patient-specific as possible and mimicking the real radiotherapy process will increase the potential advantages. In this case report, we aimed to present our patient-specific designed ECI technique managed by a multidisciplinary team of orthopedics and traumatology and radiation oncology clinics and 6 years follow-up data. As a limb preservation therapy approach, a 14-year-old female patient diagnosed with osteosarcoma underwent en-block resection, ECI with a total prescribed radiation dose of 75 Gray and reimplantation of the left femur bone. Our case results revealed that patient-specific ECI is fully effective on 6 years of local recurrence control and disease-free survival, with no postoperative complications and concomitant preservation of limb functionality.

Radiotherapy is essential for rectoanal cancer, but pelvic anatomy and high radiation doses increase radiodermatitis risk, potentially compromising treatment efficacy. No specific meta-analysis exists for this group. We systematically searched PubMed, Embase, Cochrane Library, and Web of Science up to September 2025. Pooled meta-analysis, network meta-analysis, and dose-effect meta-analysis were performed on 50 included studies (n = 4,892). The overall radiodermatitis incidence was 58.7% (95% CI: 55.2%-62.1%), including severe (Grade ≥ 3, 12.3%) and moist desquamation (34.5%). Key independent risk factors (P < 0.05) were tumor distance ≤ 5cm from anal verge (OR = 2.86), stoma absence (OR = 3.12), total dose > 50Gy (OR = 2.59), concurrent chemotherapy (OR = 2.73), HIV infection (OR = 5.82), 3D-CRT vs. IMRT (OR = 8.76), and tumor skin invasion (OR = 36.0). Effective interventions included spray-type skin protectants (SUCRA = 92.3%), volumetric modulated arc therapy (VMAT; OR = 0.29 vs. 3D-CRT), recombinant human epidermal growth factor, and amifostine. A dose inflection point occurred at 50Gy, with a 29% increased risk of severe dermatitis per additional 5Gy above this threshold. Skin toxicity is common in rectoanal cancer radiotherapy and linked to tumor, treatment, and patient factors. Optimized techniques (e.g., VMAT) combined with spray-type protectants enable precision management, improving outcomes.

Accurate 3D reconstruction of guidewires is crucial in minimally invasive surgery and interventional procedures. Traditional biplanar X-ray–based reconstruction methods can achieve reasonable accuracy but involve high radiation doses, limiting their clinical applicability; meanwhile, single-view images inherently lack reliable depth cues. To address these issues, this paper proposes a multimodal guidewire 3D reconstruction approach that integrates magnetic field information. The method first employs the MiDaS v3 network to estimate an initial depth map from a single image and then incorporates tri-axial magnetic field measurements to enrich and refine the spatial information. To effectively fuse the two modalities, we design a multi-stage strategy combining nearest-neighbor matching (KNN) with a cross-modal attention mechanism (Cross-Attention), enabling accurate alignment and fusion of image and magnetic features. The fused representation is subsequently fed into a PointNet-based regressor to generate the final 3D coordinates of the guidewire. Experimental results demonstrate that our method achieves a root-mean-square error of 2.045 mm, a mean absolute error of 1.738 mm, and a z-axis MAE of 0.285 mm on the test set. These findings indicate that the proposed multimodal framework improves 3D reconstruction accuracy under single-view imaging and offers enhanced visualization support for interventional procedures.

Low-dose simulation for grating-based X-ray dark-field radiography using a virtually decreased irradiation area.

3D tibial HU reconstruction from biplanar X-rays utilizing a hybrid PCA-CNN framework.

Thermoluminescent dosimetry properties of calcium oxide obtained from eggshells.

Combining high-dose stereotactic body radiation therapy (SBRT) with FOLFIRINOX (FFX) is promising as neoadjuvant strategy for pancreatic ductal adenocarcinoma (PDAC). This study provides an in-depth histo-molecular characterisation of resected PDAC samples from patients treated with FFX ± SBRT. Residual tumour tissues from 56 non-metastatic PDAC patients were analysed: seventeen underwent upfront surgery, seventeen received neoadjuvant FFX alone and twenty-two FFX followed by radiotherapy (sixteen SBRT, six radiochemotherapy [RT-CT]). Samples were assessed using RNAseq and immunohistochemistry/fluorescence, including multiplex. Addition of SBRT to FFX favourably remodelled PDAC, influencing stromal, immune, metabolic and molecular features. Unlike RT-CT, SBRT counteracted several detrimental effects induced by FFX alone. Notably, FFX + SBRT enriched tumours with 'Classical' and 'Inactive stroma' signatures-linked to better prognosis - while reducing 'Basal-like' cell enrichment. SBRT promoted COL1A1-driven stromal remodelling while globally preserving T-lymphocyte infiltration, including cytotoxic T cells, which maintained close proximity to tumour cells despite increased desmoplasia. Key transcriptional alterations induced by SBRT were identified, offering targets for future combination therapies. Highlighting a more favourable stromal and molecular profile after integration of high-dose SBRT to FFX, this study supports the development, rationale and validation in prospective trials of using this treatment combination in non-metastatic PDAC.

Children receive high radiation doses during interventional cardiology procedures and their sensitivity to radiation is higher than that of adults. A 4-year follow-up study was conducted in two large cardiovascular hospitals and a pediatric polyclinic with the objective of providing typical values. The median values of 454 cases obtained for fluoroscopy time, cumulative reference point air kerma (Ka,r) and air kerma-area product (PKA) by age range were 5.6min, 53.6mGy, and 4.1Gycm2 for <1y; 4.3min, 77.9mGy, and 7.2Gycm2 for 1 to <5y; 4.0min, 41.4mGy, and 7.4Gycm2 for 5 to <10y; 4.4min, 90.1mGy, and 16.1Gycm2 for 10 to <16y, respectively. The median values of 144 cases obtained for Ka,r and PKA by weight bands were 84.4mGy and 7.4Gycm2 for <15kg, 25.8mGy and 3.7Gycm2 for 15-30kg, 46.4mGy and 9.2Gycm2 for 30-50kg, and 154.0mGy and 25.6Gy·cm2 for >50kg. Our results can serve as a dose comparison with local practice and as a basis for optimization between facilities.

Genetic and Carcinogenic Risks of Radiotherapy for Nonmalignant Diseases.

Spatiotemporal variations and environmental behavior of activity concentrations of natural and artificial radionuclides in soils of Fukuoka, Japan (1980-2019).

Rationale: The efficacy of radiotherapy in triple-negative breast cancer (TNBC) is often limited by an immunosuppressive tumor microenvironment (TME), requiring high radiation doses that cause systemic toxicity. There is a critical need for theranostic strategies capable of guiding therapy and amplifying the efficacy of low-dose radiation. Methods: We developed a multifunctional organolutetium nanosensitizer (LSPA) for image-guided, low-dose radioimmunotherapy. Lutetium (Lu) serves as both a contrast agent for CT imaging and a radiosensitizer through the generation of reactive oxygen species (ROS). The LSPA nanoparticles were engineered to selectively accumulate in tumors and release their therapeutic payload in response to the acidic TME. Results: At a low 6 Gy X-ray dose, LSPA synergized with the PARP inhibitor Olaparib to induce extensive DNA damage. This activated the cGAS-STING pathway and remodeled the TME. The treatment promoted immunogenic cell death, dendritic cell maturation, and M1 macrophage repolarization. It also decreased regulatory T cells, leading to increased CD4+ and CD8+ T cell infiltration in both primary and metastatic tumors. Conclusion: This theranostic strategy suppressed primary and distant (abscopal) tumors, prevented recurrence, and established durable immune memory with low-dose irradiation. Our findings present a clinically translatable approach that combines a nanosensitizer with PARP inhibition to turn immunologically "cold" tumors into "hot" ones, thereby enhancing the efficacy of low-dose radioimmunotherapy while limiting systemic toxicity.

Ultra-high-dose rate (FLASH) radiotherapy is a promising cancer treatment method in which high doses of radiation are delivered in a very short time, minimising damage to healthy tissue while effectively targeting tumour cells. In this study, the IORT AQURE accelerator was used in FLASH mode to irradiate breast cancer cells. Dosimetric verification was carried out to confirm the quality of the beam used in the study and to control the doses (5, 10, and 15 Gy) administered to the cells. Gamma index analysis confirmed the accuracy of dose distribution, with results exceeding 96% for all cell samples. Radiobiological testing demonstrated a 90% reduction in the viability of HCC38 breast cancer cells at a dose of 15 Gy. These results validate the film dosimetry for controlling the beam and doses and the use of the AQURE accelerator in the FLASH mode for preclinical research and confirm its potential for future preclinical studies and clinical applications.

BackgroundMelanoma is an aggressive malignancy with high metastatic potential, often requiring systemic treatment with immune checkpoint inhibitors (CHI) in advanced stages. While CHI has significantly improved outcomes, its combination with local radiotherapy — particularly brachytherapy (BT) — may further enhance therapeutic efficacy by promoting immunogenic tumor cell death. BT enables precise delivery of high radiation doses, providing rapid symptom relief and potentially triggering local and systemic immune responses. This case series presents the first known clinical experience with noninvasive contact high-dose-rate brachytherapy (HDR-BT) combined with CHI in patients with metastatic melanoma treated in a palliative setting.Materials and methodsWe retrospectively analyzed four patients with stage IV melanoma and symptomatic subcutaneous metastases, all receiving ongoing CHI (nivolumab or pembrolizumab). Each underwent a single HDR-BT session (5–7 Gy) using a Freiburg Flap applicator. The primary goal was symptom relief. Treatment response was assessed clinically and radiologically, focusing on local control, response of non-irradiated lesions, progression-free survival (PFS), and overall survival (OS).ResultsAll patients experienced rapid clinical improvement and significant regression of the irradiated lesion, with minimal (Grade 0–1) acute skin toxicity. In two cases, complete remission of treated sites was achieved. One patient demonstrated long-term remission in both subcutaneous and visceral metastases. Median PFS was 3.4 months (range: 1.5–15.0), and OS ranged from 8.5 to 22 months.ConclusionsSingle-fraction contact HDR-BT in combination with CHI appears to be a safe and effective palliative strategy for metastatic melanoma, offering fast local control, minimal toxicity, and potential systemic immune benefits.

Lattice radiotherapy (LATTICE) is a technique of spatially fractionated radiation therapy (SFRT) that delivers high radiation doses to specific regions (vertices) within a large tumor, forming a spatially modulated "lattice" pattern, while surrounding areas receive lower doses to minimize damage to healthy tissues. Although the original conception of LATTICE did not prescribe any rigorous symmetry, and early clinical implementations relied on manual vertex placement tailored to tumor shape and anatomical constraints, more recent automated approaches have introduced regular patterns such as simple cubic or hexagonal arrangements. These rigid configurations, while convenient, may reduce the flexibility needed to accommodate irregular tumor geometries and nearby critical structures, potentially resulting in unintended hotspots or under-treatment. Optimizing the placement of vertices in LATTICE is beneficial for precisely targeting high-dose regions within the tumor while minimizing radiation exposure to adjacent healthy tissue, but there is still no optimization method available for solving the positions of fully flexible placed vertices. The great challenge in such optimization lies in handling the constraints on the relative positions between different vertices. This work aims to develop a new treatment planning method for LATTICE with fully flexible placement of vertices and simultaneous optimization of the position of each lattice vertex and dose, to improve overall plan quality compared with conventional LATTICE planning methods relying on manual regular placements of lattice vertices. The proposed method simultaneously optimizes each lattice vertex position and other plan optimization variables (proton spot weights or photon fluences) during the dose optimization process. This is formulated as a new constrained optimization problem by adding each lattice vertex position to optimization variables with appropriate constraints to meet the requirements of the LATTICE vertices placement guideline on the 1) center-to-center distance between lattice vertices and 2) distance of lattice vertices to the target boundaries. The optimization problem is solved by the alternating direction method of multipliers and iterative convex relaxation methods. Plans generated using our proposed method (NEW) were compared with conventional LATTICE plans for two representative patient cases presented in the main manuscript: one abdominal and one lung tumor. To maintain brevity, two additional patient cases are included in the Supporting Information to further demonstrate the performance and generalizability of the proposed method. For each case, we generated 100 LATTICE plans with varying vertex positions. From these, three plans-termed BEST, MID, and WORST-were selected based on the largest, median, and smallest total optimization objective value . All LATTICE plans optimized with the NEW method showed results comparable to, or better than, the BEST plans. For example, for photon LATTICE abdomen plans, the values of F were 1.92 (NEW), 2.79 (WORST), 2.27 (MID), and 1.96 (BEST), representing a 31.1% improvement from WORST to NEW; the PVDR values were 5.88 (NEW), 3.00 (WORST), 4.33 (MID), and 5.16 (BEST), representing 96.0% and 14.0% improvements relatively from WORST and BEST, respectively to NEW. A new LATTICE treatment planning approach is introduced, in which lattice positions are fully flexible and optimized simultaneously with dose distribution, leading to improved target PVDR and OAR sparing compared to conventional LATTICE methods with regularly spaced vertices.

Mini-GRID enhances survival and reduces toxicity in an orthotopic murine model of oral squamous cell carcinoma: A proof-of-concept study

BackgroundComputed tomography is a highly effective diagnostic tool for evaluating pathological conditions of the temporal bone. However, the relatively high radiation doses pose risks to radiosensitive organs, making dose optimization essential in accordance with the ALARA principle. Recent technological advances, such as tin‐based photon‐shaping filters, have enabled significant dose reduction in both dual‐ and single‐energy CT without compromising image quality.PurposeTo evaluate the impact of a spectral shaping tin filter on image quality and radiation dose in temporal bone CT examinations.MethodsThirty‐six patients undergoing temporal bone CT were retrospectively analysed. Group A (n = 13) underwent standard CT, while Group B (n = 23) underwent CT examination using 150 kVp beam with additional tin filtration. Images were reconstructed with model‐based iterative reconstruction (ADMIRE, level 3) and assessed by two neuroradiologists using a 3‐point Likert scale. Radiation dose was quantified via CTDIvol, DLP, and eye lens dose using Monte Carlo simulations.ResultsBoth protocols provided diagnostic‐quality images. The protocol with tin filter achieved slightly superior image quality (median scores: overall 3.00 vs. 2.88, contrast 3.00 vs. 2.96, resolution 2.58 vs. 2.53; p < 0.05) with substantial inter‐rater agreement (κ = 0.75–0.97). Mean CTDIvol and DLP decreased from 59.1 ± 12.1 mGy and 551.8 ± 226.8 mGy×cm (Group A) to 39.9 ± 1.7 mGy and 302.4 ± 33.8 mGy×cm (Group B) (p < 0.001). Eye lens dose was reduced by 34% (54.7 ± 10.9 mGy vs. 36.4 ± 2.2 mGy, p < 0.001).ConclusionsIncorporating a tin filter into temporal bone CT significantly reduces radiation exposure, including lens dose, without compromising—and in some cases slightly improving—image quality. Routine implementation of spectral shaping may enhance patient safety in clinical practice.

BackgroundSpinal chondrosarcomas are rare, aggressive bone tumors with limited data on optimal radiotherapy strategies, particularly regarding the comparison between proton and photon therapies. This study aims to evaluate long-term survival outcomes and identify effective treatments and risk factors using the National Cancer Database.MethodsPatients diagnosed with spinal chondrosarcomas were categorized into radiation and no-radiation groups. The radiation group was subdivided into proton and photon therapy cohorts. Univariate and Kaplan–Meier analyses assessed demographic, clinical, and survival outcomes. Multivariate Cox proportional hazards models identified prognostic factors, and survival predictive models were evaluated using Area Under the Curve (AUC) metrics.ResultsOf 1971 patients, 343 (17.4%) received radiation. Surgery was less common in the radiation group (53.9% vs 82.6%, P < .001). Combined surgery and radiation had the best survival outcomes, with proton therapy showing superior survival to photons (P < .001). High-dose radiation (Biologically Effective Dose [BED] >70 Gy) and Stereotactic Body Radiation Therapy (SBRT) improved survival (P < .001). Surgery was associated with increased mortality risk (hazard ratio [HR] = 0.35, P < .001), while radiation showed increased risk (HR = 1.31, P = .003). Machine learning identified tumor size thresholds of 75 mm for photon and 70 mm for proton therapy as predictive of mortality. DeepSurv (AUC = 0.708) identified distant metastasis, tumor size, and age as important prognostic factors for 10-year survival.ConclusionGross total resection (GTR) is the most effective treatment for spinal chondrosarcoma. High-dose radiation therapy (BED > 70 Gy) can be combined with surgery to improve survival in advanced cases. Proton therapy offers superior long-term survival compared to photons, and dose-escalated techniques (Stereotactic Radiosurgery [SRS] and Intensity-modulated radiation therapy [IMRT]) show potential in enhancing outcomes.