Radiation

Background: Cancer patients receiving or having received radiotherapy (RT) represent a clinically vulnerable group during the COVID-19 pandemic. However, systematic data on their clinical course, comorbidities, and vaccination status are limited. The German National Pandemic Cohort Network (NAPKON), established to systematically collect comprehensive clinical data on COVID-19 patients nationwide, provides a unique opportunity to address this gap. This study aimed to describe radiation therapy patterns and COVID-19-related clinical characteristics among patients documented within the NAPKON Cross-Sectoral Platform (SUEP). Methods: This multicenter, descriptive analysis was conducted within the framework of the German National Pandemic Cohort Network (NAPKON). All patients with documented RT and confirmed SARS-CoV-2 infection were identified in the SUEP database. RT was classified relative to the documented infection date as occurring before, during, or after infection. Demographic, clinical, laboratory, imaging, and vaccination data were extracted and analyzed descriptively. Due to the small sample size, no correlation or multivariable analyses were performed. Results: A total of n = 90 patients were included in the analysis. The median age was 65 years (range 22–90), and 56% were male. Most patients (93%) received one course of RT, most frequently targeting specific organ systems (54%), while total body irradiation was performed in 4%. The median radiation dose was 45 Gy (IQR 30–60). Among 68 patients with evaluable timing information, RT had been administered before infection in 53 patients (77.9%), during infection in 3 patients (4.4%), and after infection in 12 patients (17.6%). At the time of SARS-CoV-2 detection, 76% of patients experienced a phase without complications, 19% a phase with complications, and 2% a critical phase. The majority of vaccinated individuals had received Comirnaty (BioNTech/Pfizer; 80%). COVID-19-typical findings were identified in 18% of chest X-rays and 27% of CT scans. Clinical and laboratory characteristics showed no substantial differences by hospital length of stay. Conclusions: Patients with documented RT and SARS-CoV-2 infection in the NAPKON registry predominantly experienced mild or moderate COVID-19 courses and showed a relatively high vaccination uptake. However, due to the descriptive study design and the absence of a control group, these findings should not be interpreted as being attributable to RT itself but rather as a characterization of this registry cohort. Importantly, the cohort mainly comprised patients with a history of RT before SARS-CoV-2 infection, whereas only a small minority received RT during infection. Although the analysis was descriptive and limited by missing data, it demonstrates the feasibility and scientific value of integrating oncologic subcohorts within national pandemic research networks. Continued longitudinal analyses will be essential to further characterize outcomes of patients with cancer and RT in future pandemics. Full article

Cancer remains a significant global health burden, often requiring conventional treatments characterized by considerable side effects and limited tumor specificity. This review addresses the critical gap in understanding the non-thermal mechanisms by which Pulsed Electromagnetic fields (PEMFs) exert selective anti-tumor effects. Our primary objective is to analyze the molecular and cellular events through which low-intensity PEMF triggers stress responses and apoptosis in neoplastic cells without impacting normal cell viability. This comprehensive review synthesizes current evidence on the biological effects of PEMFs. Findings indicate that PEMFs disrupts intracellular homeostasis, induces reactive oxygen species-mediated oxidative stress, and activates endoplasmic reticulum stress, collectively driving malignant cells towards apoptosis or cell cycle arrest. Importantly, these effects are preferentially observed in cancer cells due to their inherent biophysical vulnerabilities—such as depolarized membrane potentials—and depend critically on specific PEMFs parameters. In conclusion, PEMFs acts as a multifaceted disruptor of cancer cell homeostasis, representing a promising non-invasive therapeutic modality. Further research is essential to optimize dosimetry and identify primary molecular sensors such as radical pair dynamics, to enhance clinical application and explore synergistic combinations with existing therapies. Full article

Background/Objectives: Hemangioblastomas are rare, benign, highly vascular tumors of the central nervous system, frequently associated with von Hippel–Lindau (vHL) disease. Case Presentation: We report a 16-year-old female with vHL presenting with recurrent headaches, abdominal distension, and ocular discomfort. Imaging revealed hemangioblastomas in the fourth ventricle and retrobulbar space, alongside multiple pancreatic cysts. The patient underwent three sessions of Gamma Knife Surgery (GKS) with initial tumor regression and symptom relief. However, long-term follow-up demonstrated progressive disease, with new lesions in the cerebellum, spinal cord, and orbit, including cystic transformation. Histopathology confirmed the reticular variant of hemangioblastoma. Despite further radiosurgical and surgical recommendations, the patient and family opted for conservative management, with lesions remaining radiographically stable over nine years. Conclusions: This case demonstrates that Gamma Knife Surgery may provide temporary local disease control for selected solid hemangioblastomas in von Hippel–Lindau disease but does not alter the underlying disease course. Long-term radiographic stability should be interpreted cautiously, as hemangioblastomas exhibit saltatory growth patterns that make it difficult to distinguish treatment effect from natural tumor quiescence. These findings emphasize that radiosurgery should be regarded as a disease-control strategy rather than curative therapy, underscoring the importance of individualized management, multidisciplinary decision-making, and prolonged surveillance. Full article

Introduction: Lattice Radiation Therapy (LRT) is an evolving spatially fractionated radiation therapy (SFRT) technique that delivers heterogeneous dose distributions to large and radioresistant tumors. The literature highlights LRT’s potential for effective tumor debulking, palliation, and immune modulation. Effective LRT planning is crucial for maximizing tumor control while minimizing toxicity to organs at risk (OARs). The process involves defining the size, spacing, and arrangement of high-dose vortexes within the GTV. Traditionally, this has been a manual and time-consuming process, prone to inter-planner variability in vortex placement. Recent research has focused on developing automated or semi-automated tools to address these challenges, enhancing planning standardization. We aimed to systematically review for the first time the available scientific evidence of automated planning tools of vortexes for Lattice Radiotherapy and to assess the efficacy of such tools for standardizing Lattice Radiotherapy delivery. Methods: A systematic review of available studies in PubMed, Web of Science, and Scopus, including the terms “Lattice radiation therapy and (automated or optimized)”. Only LRT clinical planning reports published in English and with access to the full accepted text were considered eligible. This study was conducted in accordance with the PRISMA guidelines and was registered on the PROSPERO platform (CRD420251108024). Results: A total of 82 articles were found. Twenty articles fulfilled all inclusion criteria. Automated treatment planning tools have significantly improved the efficiency, consistency, and scalability of LRT planning, addressing limitations of manual planning. In conclusion, LRT should be planned to use automated tools to improve wide clinical standardization and implementation. Full article

This retrospective study evaluated patient radiation dose during fluoroscopy-guided peripherally inserted central catheter (PICC) placement. A total of 1240 consecutive adult patients who underwent PICC placement between January 2023 and December 2024 were analyzed. Patient radiation dose indices, including air kerma (AK) and dose–area product (DAP), as well as fluoroscopy time and number of radiographic acquisitions, were obtained from the radiology information system. The mean and median AK were 2.47 mGy and 1.54 mGy, respectively, and the median DAP was 901.9 mGy·cm². The median fluoroscopy time was 1.9 min, and the median number of radiographic acquisitions was 1. Patient radiation dose during PICC placement was lower than the Japanese Diagnostic Reference Levels (Japan DRLs 2025). AK showed a strong positive correlation with fluoroscopy time (Spearman’s rank correlation, $\rho$ = 0.77), whereas correlations between AK and BMI or the number of radiographic acquisitions were weak. In some patients with high BMI, AK values exceeding 40 mGy were observed. These findings indicate that patient radiation dose during PICC placement is generally low but remains closely associated with fluoroscopy time. Optimization of the patient radiation dose should be considered, particularly for patients with high BMIs or those undergoing repeated PICC placements. Full article

Stereotactic body radiation therapy (SBRT) for localized prostate cancer delivers high doses per fraction, making dose constraints for the rectum and other organs at risk critical during treatment planning. This study evaluated the association between prostate–rectum separation, achieved with a biodegradable balloon rectal spacer at different anatomical levels, and corresponding organ-at-risk dose patterns. Thirty-three patients underwent transperineal balloon spacer implantation followed by SBRT to 36.25 Gy in five fractions. Prostate–rectum separation at the apex, mid-gland, and base were measured on CT and/or MRI and categorized as <10 mm, 10–14 mm, or ≥14 mm. Rectal dose–volume parameters and mean doses to the rectum, bladder, and penile bulb were assessed using linear regression analyses and group comparisons at 14 mm separation. Mean prostate–rectum separation was 16.6 mm overall, with minimal high-dose rectal exposure observed. Increasing separation was associated with reduced rectal dose–volume parameters at the apex and mid-gland, while greater base separation corresponded primarily to lower bladder mean dose. Increased apical separation was also associated with reduced penile bulb mean dose. No acute gastrointestinal toxicity was observed, and genitourinary toxicity was limited to low-grade events. These findings indicate that prostate–rectum separation varies by anatomical level and is associated with distinct organ-at-risk dose relationships in prostate SBRT. Full article

Proton therapy offers superior dose localization, yet the biological effects of low-energy protons relevant to superficial tissues remain underexplored. We report the design and validation of a proton irradiation setup developed at the Tandem Accelerator of NCSR “Demokritos” for controlled radiobiological experiments. Monte Carlo simulations using Geant4 and Monte Carlo Damage Simulation (MCDS—Monte Carlo Damage Simulation) were used to determine proton energy spectra, linear energy transfer (LET), and predicted DNA damage yields. A single layer (15–20 μm in thickness) of human keratinocytes (HaCaT) was irradiated at doses from 0.65 to 3.65 Gy, and γ-H2AX foci were quantified as markers of tracks including one or more DNA double-strand breaks. The system achieved a uniform dose rate of 0.37 Gy/min, as calculated with Geant4, with a mean proton energy of 4.1 MeV (LET ≈ 8 keV/μm). A strong correlation (R² = 0.93) was observed between proton dose and γH2AX foci per nucleus (~10 foci/Gy), reflecting damage-inducing proton tracks rather than individual DNA double-strand breaks. At higher doses, an increased fraction of cells exhibited pan-nuclear γH2AX staining, characterized by a diffuse γH2AX signal throughout the nucleus and commonly associated with extensive or clustered DNA damage and global chromatin phosphorylation. These responses are consistent with the well-established dense ionization patterns produced by low-energy protons, as indicated by the LET spectrum and supported by MCDS-predicted clustered damage yields. While the γH2AX assay does not directly resolve simple versus complex DNA lesions, the agreement between Monte Carlo modeling and the observed cellular stress responses indicates that the irradiation platform reliably reproduces the expected biological signatures of low-energy proton exposure. Consequently, the developed system provides a robust experimental tool for systematic investigations of cellular radiosensitivity and radiotoxicity, with potential applications in skin dosimetry and radioprotection. Full article

Anesthesia is the gold standard for immobilization of tumor-bearing mice before radiotherapy which potentially induces stress and distorts disease progression. Irradiation of preclinical cancer models with clinical MV linear accelerator (LINAC) beams can benefit the translation of new strategies in radiation oncology. However, logistical constraints prohibit widespread use of clinical facilities. Currently, there is no detailed protocol on how to safely introduce mice to a clinical environment to be intervened on using hospital equipment. Here, a facile and high-throughput handling method is described that eliminates anesthesia and enables fractionated radiotherapy of multiple mice simultaneously for high-throughput studies. Subcutaneous breast tumor-bearing BALB/c mice were restrained in plastic restraint cones within a containment tray and received four fractions of 4 Gy X-rays from a 6 MV LINAC source over two weeks (two fractions/week). Both short- and long-term follow-up revealed no identifiable health issues or complications associated with the restraint procedure or radiation exposure in terms of body weight loss, skin burns or body condition scores. This method not only benefits animal welfare but also data quality by reducing stress/discomfort levels and confounding effects of anesthetics. It can be applied to a broader range of studies where mice need to be immobilized before intervention. Full article

Background: One method for the radiation therapy of rectal cancer is to set patients supine and treat them with volumetric modulated arc therapy (VMAT). The posterior skin dose is of concern due to undesirable bolusing from mounting surfaces the patient lays upon, namely the carbon fiber couch (CFC). The posterior skin dose may be mitigated by positioning the patient on top of a low-density material that separates the patient from the CFC. Purpose: Our objective was to determine the reduction in the posterior surface dose when a mattress or foam board is used to prop the patient away from the CFC. Materials and Methods: Three clinical rectal cancer patient VMAT plans were selected. A solid water phantom with optically stimulated luminescence dosimeters (OSLDs) placed at the posterior surface was mounted using three setups: directly on the CFC, with a mattress on the CFC, and with a 10 cm thick foam board on the CFC. The three VMAT plans were delivered to this phantom, with OSLDs measuring the posterior surface dose with each setup. In the treatment planning system (TPS), the CFC only, mattress, and foam board setups were simulated on the patient’s anatomy with posterior surface doses reported. Results: The OSLD measurements in the phantom showed that the mattress reduced the posterior surface dose on average by 1.3%, and the foam board reduced the dose by 8.3%. The TPS estimates demonstrated that, on average, the mattress reduced the surface dose by 15.8%, and the foam board reduced the dose by 33.0%. It is likely that the TPS had limitations accurately modeling the surface dose, so OSLD measurements were closer to clinical reality. Conclusions: The mattress does not reduce the posterior skin dose enough to warrant its use as a skin sparing device. The CFC produces a bolusing effect that can be reduced by separating the patient from the CFC with a 10 cm thick foam board. Full article

Background: Interpretation of radiographs is prone to diagnostic errors. Artificial intelligence (AI) has shown promising results in fracture detection, although systematic evaluation of software updates remains limited. This study compares the diagnostic performance of two versions of an AI-based fracture detection software in hand and ankle radiographs and assesses the influence of AI output on diagnostic decisions. Methods: This retrospective diagnostic accuracy study included 193 hand and ankle examinations obtained during routine clinical practice at Lillebaelt Hospital, Denmark. Radiographs were analysed using two versions of the same AI software and compared with the diagnostic report as the reference standard. Diagnostic performance of both versions was assessed using diagnostic accuracy metrics. Exploratory subgroup analyses were conducted to further investigate the difference in performance. The influence of AI was evaluated by the proportion of reports revised after review of AI output. Results: The newest software version demonstrated higher diagnostic performance than the older one (accuracy 0.933 vs. 0.824; p < 0.001). Similar improvements were observed across patient subgroups. Excluding radiographs containing casts resulted in only minimal changes in performance (accuracy in version 2: 0.930 vs. 0.933). In 8 of 15 discordant cases, reporting radiographers revised the initial assessment upon reassessment. Conclusions: The newest version demonstrated higher overall diagnostic performance, indicating that software updates can enhance the accuracy of AI-assisted fracture detection. The proportion of revised assessments suggests that radiographers’ decisions may be influenced by AI output. Full article

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide. Pulmonary function tests (PFTs) and quantitative indices (QIs) of computed tomography (CT) are typically used to diagnose COPD. The purpose of this work was to determine the correlation of the vector divergence operator with PFTs and QIs in COPD patients and compare the divergence of normal lung function to that in COPD. Vector divergence is computed for 73 patients with four-dimensional CT scans retrospectively identified as normal (n = 37) and COPD (n = 36), which includes emphysema (n = 13). The divergence is the flux per unit volume at a point in a vector field and reflects the local lung tissue expansion when the data are taken during inspiration. The divergence measures are strongly correlated with both PFTs and QIs of COPD patients and therefore are a useful biomarker in analyzing regional lung function. In physical terms, the divergence shows that there is a significant difference in lung tissue expansion between normal subjects and patients with airflow obstruction as in emphysema and COPD. The divergence analysis also enables new images using color overlays to provide a functional measure (local expansion capability) to the anatomical CT image. Full article

Breast cancer remains a major global health challenge, with treatment access further constrained during the COVID-19 pandemic, particularly in resource-limited settings. This study evaluates the in vitro effects of hypofractionated versus conventionally fractionated radiotherapy on three breast cell lines: MCF-7 (oestrogen receptor-positive, ER⁺/PR⁺), MDA-MB-231 (triple-negative: ER⁻/PR⁻/HER2⁻), and MCF-10A (non-tumorigenic mammary epithelial). Cells were exposed to cobalt-60 γ-rays, and radiobiological endpoints assessed included clonogenic survival, α/β ratios, adaptive responses, migration, invasion, and cytotoxicity through lactate dehydrogenase assays. The α/β ratios ranged from 2.5 to 5.4 Gy across breast cancer subtypes. Hypofractionation reduced survival in hormone receptor-positive cells, whereas triple-negative cells exhibited increased survival. Adaptive radiation responses enhanced viability across all cell lines, while non-cancerous MCF-10A cells demonstrated reduced migration following treatment. These findings suggest that hypofractionated radiotherapy may be beneficial in hormone receptor-positive breast cancer, while triple-negative disease may show a trend toward different responses, although this was not statistically significant (MDA-MB-231, p = 0.290). The results underscore the importance of tailoring fractionation strategies to breast cancer subtype and highlight the translational potential of preclinical radiobiology in guiding personalised radiation oncology approaches. Full article

We compared scatter correction (SC) in single-photon emission computed tomography (SPECT) images using effective scatter source estimation (ESSE) and the triple-energy window (TEW) method. We acquired ^99mTc and ¹²³I images of brain, myocardial, and performance phantoms containing rods with different diameters. We assessed contrast ratios (CRs) and ROI-based noise metrics (coefficient of variation, signal-to-noise ratio, and contrast-to-noise ratio [CNR] ). Under ^99mTc, ESSE yielded higher CRs than TEW across all phantoms (mean difference 0.04, range 0.01–0.05) and produced the highest CNR in the myocardial phantom, improving the conspicuousness of the simulated defect. Under ¹²³I, CR differences between ESSE and TEW were small and inconsistent (performance phantom: −0.04 to 0.06; brain phantom: −0.01 to 0.00). A Monte Carlo simulation (point source in air) showed substantial photopeak window penetration for cardiac high-resolution collimators (40.0%) but low penetration for medium-energy general-purpose collimators (5.1%), supporting photopeak contamination as a contributor to the ¹²³I findings and potentially attenuating the apparent advantage of model-based SC that does not explicitly account for penetration photons. These findings suggest that SC selection should consider the radionuclide and imaging target and that ESSE might be a reasonable option for ^99mTc myocardial imaging under the settings examined. Full article

Radiopharmaceutical therapy (RPT) offers tumor-selective radiation delivery and represents a promising platform for combination with immune checkpoint inhibitors (ICIs). While prior studies suggest that RPT can stimulate antitumor immunity, synergy with ICIs may depend on radionuclide properties, absorbed dose, and radiation distribution within the tumor microenvironment. This study evaluated how radionuclide selection and dose influence immune stimulation and therapeutic efficacy of GD2-targeted antibody-based RPT combined with ICIs. Dinutuximab, an anti-GD2 monoclonal antibody, was radiolabeled with β⁻-emitters (⁹⁰Y, ¹⁷⁷Lu) or an α-emitter (²²⁵Ac). C57Bl6 mice bearing GD2⁺ tumors received 4 or 15 Gy tumor-absorbed doses, determined by individualized dosimetry, with or without dual ICIs (anti-CTLA-4 and anti-PD-L1). In vivo imaging, ex vivo biodistribution, survival, histological, and gene expression analyses were performed to assess therapeutic and immunological outcomes. All radiolabeled constructs demonstrated preferential uptake in GD2⁺ tumors. Combination therapy improved survival in a radionuclide- and dose-dependent manner, with the greatest benefit in the ²²⁵Ac + ICI group at 15 Gy. Treatment activated type I interferon signaling and increased MHC-I and PD-L1 expression. Notably, ⁹⁰Y reduced regulatory T cells, enhancing CD8⁺/Treg ratios, while ²²⁵Ac induced robust interferon-driven activation. Radionuclide selection and absorbed dose critically shape immune and therapeutic outcomes of antibody-based RPT combined with ICIs, underscoring the importance of delivery mechanism and dose optimization in combination therapy strategies. Full article

Purpose: This study aimed to compare QoL outcomes among patients undergoing active breathing control (ABC), voluntary deep inspiration breath hold (vDIBH), and surface-guided radiation therapy (SGRT). Methods: This was a non-randomized, three-arm clinical trial in which 55 patients were sequentially allocated to ABC (n = 19), SGRT (n = 20), or vDIBH (n = 16). QoL was assessed using the European Organization for Research and Treatment of Cancer QoL questionnaire (EORTC QLQ-C30) at baseline, treatment completion, and 6–8 weeks post-treatment. Linear regression was used to compare changed scales in QoL domains across groups. A p-value of <0.05 was considered statistically significant. Results: Baseline QoL scores were high across all groups, with physical functioning being the highest-rated domain and global health status the lowest. Fatigue, pain, and insomnia were the most highly reported symptoms at all time points. At 6–8 weeks, social functioning improved significantly in SGRT compared to vDIBH (16.67 vs. −12.50, p = 0.0053). Patients in the vDIBH group reported significantly increased pain compared to ABC at 6–8 weeks (p = 0.0240). No other significant differences were observed in QoL changes between the groups. Conclusions: The three breath-hold techniques maintained overall QoL with no differences between the groups, except for pain between vDIBH and ABC and social functioning for vDIBH and SGRT both at 6–8 weeks of follow-up. Despite the limitations of this study, each breath-hold technique has demonstrated comparable impact on QoL in patients with left-sided breast cancer and each could be used as a viable option with respect to QoL. Full article

Introduction. This study aims to conduct a cost-effectiveness analysis comparing two primary treatment approaches: radical prostatectomy versus radiotherapy plus androgen deprivation therapy (ADT) in patients with Prostate Imaging Reporting and Data System (PI-RADS) 5 lesions. Patients and Methods. Data were extracted from two published retrospective cohort studies. Using survival data from two retrospective studies, we reconstructed Kaplan–Meier curves, overlaid them for comparative metasurvival analysis, and developed a cost-function model to assess economic implications alongside clinical outcomes. The primary outcomes included biochemical recurrence-free survival (FFBF) at 2 and 5 years; the area under the survival curve; total cost per treatment strategy; and cost per recurrence-free patient at 5 years. Results. At 5 years, the estimated FFBF was 83% for radiotherapy vs. 28% for prostatectomy. Radiotherapy yielded an AUC of 80.7, while prostatectomy showed 41.9. Radiotherapy yielded a cost of 21,211 € per FFBF patient compared to 113,730 € for prostatectomy. Conclusion. Our study demonstrates that radiotherapy combined with ADT, when selected based on mpMRI stratification, may represent a cost-efficient alternative, pending prospective validation. To radical prostatectomy in patients with PI-RADS 5 prostate cancer, with a favourable cost–benefit profile. Full article

Radiation therapy (RT) has been one of the standard treatments for prostate cancer; however, its potential impact on nearby neural structures, such as the lumbosacral plexus (LSP), is often overlooked. The lack of contouring in treatment plans has led to unintended consequences. Radiation-induced lumbosacral plexopathy (RILSP) is a rare but serious complication that presents with progressive lower extremity sensory changes and weakness, mimicking radiculopathy. We report the case of a 66-year-old male who developed bilateral lower extremity neurological deficits post-pelvic radiation for prostate cancer. Radiographically, no compressive lesions were found, and the Electromyography (EMG) revealed involvement of nerves inconsistent with radiculopathy. This led to the diagnosis of RILSP. This case highlights the importance of recognition of RILSP in contrast to radiculopathy in patients with unexplained neurological symptoms after pelvic RT. This highlights the importance of incorporating the LSP as an organ at risk while planning for RT and reviewing retrospectively the dosimetry. It also emphasizes the need for improved contouring of LSP in radiation planning to minimize adverse effects. This sentiment is reflected in the literature, along with the consensus that more research is needed to address the true rate of RILSP. Full article

High doses of ionizing radiation during prenatal development can cause growth restriction, or a decrease in growth of the developing offspring. This outcome of intrauterine growth restriction (IUGR) can predispose the offspring to lifelong health outcomes, which is referred to as developmental programming. The role of the placenta in radiation-induced IUGR was investigated using a mouse model. Pregnant BALB/cAnNCrl mice were externally irradiated with 1.82 Gy x-ray irradiation on gestational day 14.5. Fetoplacental units were collected on gestational day 18.5, and growth restriction was observed in irradiated offspring. Whole placenta samples from growth restricted and sham-irradiated groups were analyzed via RNA-sequencing analysis. Differential gene expression (DEG) analysis revealed a total of 166 DEGs in the irradiated samples. Validation of these DEG findings were completed using RT-qPCR analysis. Gene ontology (GO) analysis of the DEGs supported the involvement of autoimmune response and dysregulation in retinol (vitamin A) metabolism in the placenta. Upstream prediction analysis identified a number of potential regulators responsible for the DEG profiles including Nppb, Myod1 and genes of the classic complement system (Complement C1q chains C1qa, C1qb, C1qc). Overall, these findings present an overview of the dysregulation in the mouse placenta following an acute, high-dose radiation exposure. Full article

Online adaptive radiotherapy mitigates errors in absorbed dose delivery due to daily anatomical changes during hypofractionated breast treatment, particularly when comprehensive nodal therapy includes the internal mammary chain. To illustrate this, we present a case of a 65-year-old woman with left-sided luminal B invasive carcinoma, who underwent segmentectomy and level 1–2 dissection. Pathology revealed an 18 × 15 × 13 mm primary tumor with lymphovascular invasion, two of eleven axillary nodes positive, and intramammary metastasis, staged pT1cN1a. She received adjuvant docetaxel–cyclophosphamide followed by letrozole. Hypofractionated radiotherapy (40 Gy in 15 fractions) was administered in an inspiration breath-hold setting using a CBCT-guided online-adaptive platform. Adaptive planning improved V95% coverage over the planned treatment for all targets: on average, whole breast coverage increased from 88.4% to 96.3%, supraclavicular from 93.0% to 97.1%, axilla from 90.6% to 96.7%, and internal mammary from 91.8% to 95.9%. Organ-at-risk metrics remained within limits: the mean heart dose increased slightly (from an average of 0.12 Gy in scheduled to 0.15 Gy in adaptive plans). At the same time, the LAD D0.03 cm³ decreased, and the heart V4 Gy fell modestly (from 13.3% in the scheduled plan to 8.2% in the adaptive plan), reflecting low-dose redistribution without exceeding constraints. Lung and thyroid mean doses remained comparable. The patient tolerated treatment well, with no acute toxicity or local recurrence. This case highlights the importance of daily adaptation for complex left-sided radiation treatment involving internal mammary nodes, demonstrating target recovery without exceeding absorbed dose constraints and supporting future studies on control, toxicity, and quality of life. Full article