Advances in Radiation Oncology最新文献

{"title":"FLASH Stereotactic Body Radiation Therapy for Spine Tumors Using a Single-Energy Proton Pristine Bragg Peak Delivery Technique","authors":"Balaji Selvaraj PhD ,&nbsp;Xingyi Zhao MS ,&nbsp;Haibo Lin PhD ,&nbsp;Jiajian Shen PhD ,&nbsp;Chingyun Cheng PhD ,&nbsp;Alex Bookbinder BS ,&nbsp;Hui Wu MD ,&nbsp;Huifang Zhai MS ,&nbsp;J. Isabelle Choi MD ,&nbsp;Arpit M. Chhabra MD ,&nbsp;Shaakir Hasan DO ,&nbsp;Charles B. Simone II MD ,&nbsp;Yoshiya Yamada MD ,&nbsp;Minglei Kang PhD","doi":"10.1016/j.adro.2025.101776","DOIUrl":"10.1016/j.adro.2025.101776","url":null,"abstract":"<div><h3>Purpose</h3><div>To investigate the dosimetric performance and dose rate of Bragg peak FLASH (BP-FLASH) for spinal cord stereotactic body radiation therapy (SBRT).</div></div><div><h3>Methods and Materials</h3><div>Ten consecutive patients with spinal tumors treated with conventional intensity modulated proton therapy (CONV-IMPT) SBRT (40 Gy in 5 fractions) were selected for this study. These patients were reoptimized using an in-house FLASH algorithm and a single-energy Bragg peak approach. The dose distributions and dose metrics for target coverage and critical organs-at-risk (OARs) were compared. BP-FLASH plans dose rates were calculated using an average-dose-rate. The FLASH ratios (V_40Gy/s) were assessed with dose thresholds at 0.2, 2, and 5 Gy. The doses and dose rates for the 10 patients were averaged, and a <em>t</em> test was performed comparing CONV-IMPT and BP-FLASH.</div></div><div><h3>Results</h3><div>Dosimetric analysis revealed that the BP-FLASH plans deliver a similar dose as CONV-IMPT plans to critical OARs. However, in BP-FLASH, the clinical target volume received a higher maximum dose than CONV-IMPT (115.1% versus 108.9%, <em>P</em> = .001). No notable differences were observed in the maximum doses to the spinal cord (<em>P</em> = .122) or esophagus (<em>P</em> = .327). FLASH dose rates for all the OARs exceeded 80% with 2 Gy dose threshold. When increased to 5 Gy, V_40Gy/s increased to &gt;95% for composite plan doses.</div></div><div><h3>Conclusions</h3><div>BP-FLASH SBRT is a promising treatment for challenging spinal cord cancers, which achieved ultra-high-dose rates for FLASH effect and maintained the same dosimetry quality as the CONV-IMPT plans.</div></div>","PeriodicalId":7390,"journal":{"name":"Advances in Radiation Oncology","volume":"10 6","pages":"Article 101776"},"PeriodicalIF":2.2,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143890549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Representation of Radiation Oncologists on National Comprehensive Cancer Network Guideline Committees","authors":"Bismarck C. Odei MD ,&nbsp;Temitope Agabalogun MD ,&nbsp;Erika Bello-Pardo BS ,&nbsp;Christina Huang MD, MS ,&nbsp;Daniel Vanderbilt MD, PhD ,&nbsp;Seyi Omeh MD, MPH ,&nbsp;Benjamin Sterling ,&nbsp;Fumiko Chino MD","doi":"10.1016/j.adro.2025.101773","DOIUrl":"10.1016/j.adro.2025.101773","url":null,"abstract":"<div><h3>Purpose</h3><div>The National Comprehensive Cancer Network (NCCN) guideline committees (GCs) play a vital role in defining the standard of care for cancer management. Equitable specialty representation is crucial for unbiased recommendations and perspectives. This study examines the specialty and leadership representation on NCCN GCs, with a focus on radiation oncologists (ROs).</div></div><div><h3>Methods and Materials</h3><div>This cross-sectional observational study evaluated committee member characteristics on NCCN treatment GCs available in 2020 and subset of committees with guidelines containing category 1 or 2A radiation therapy recommendations. Collected data included member characteristics and committee roles. Interspecialty variance was evaluated via χ² tests.</div></div><div><h3>Results</h3><div>A total of 1768 NCCN committee members were identified, representing 54 NCCN GCs with a median committee size of 33 (range, 22-38). Among all members: 47.6% were medical oncologists (MOs), 20.9% were surgical oncologists (SOs), and 8.9% were RO; 22.6% were other specialists. Women accounted for 37.6% (316/841) of MO, 34.2%(54/158) of RO and 22.8% (84/369) of SO members (<em>P</em> &lt; .001). RO representation varied based on disease site (2.4%-29.9%; 15 individual committees had no RO representation) and in leadership roles (3% chairs, 23% vice chairs). On 38 committees with guidelines containing category 1 or 2A radiation therapy recommendations, the pattern of low representation persisted (8.4%). Although 39% of individuals on all committees were women, only 23% of committee chairs were women (<em>P</em> = .048).</div></div><div><h3>Conclusion</h3><div>There is low representation of ROs on NCCN GCs and in leadership roles, which may limit the discussion during guideline development and negatively impact the diversity of perspectives in management recommendations.</div></div>","PeriodicalId":7390,"journal":{"name":"Advances in Radiation Oncology","volume":"10 6","pages":"Article 101773"},"PeriodicalIF":2.2,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143950461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimizing Dose Reduction to the Left Anterior Descending Artery in Patients With Locally Advanced Lung Cancer Treated With Definitive Radiation Therapy: A Feasibility Study of Coplanar Treatments Using Double-Stacked Multileaf Collimator","authors":"Joshua P. Kim PhD ,&nbsp;Justine M. Cunningham MS ,&nbsp;Emily Moats CMD ,&nbsp;Ahmed I. Ghanem MD, PhD ,&nbsp;Benjamin Movsas MD ,&nbsp;Kenneth Levin MD ,&nbsp;Aharon M. Feldman MD ,&nbsp;Kundan Thind PhD","doi":"10.1016/j.adro.2025.101779","DOIUrl":"10.1016/j.adro.2025.101779","url":null,"abstract":"<div><h3>Purpose</h3><div>Recent studies have shown that cardiac substructures and particularly left anterior descending artery (LAD) dose strongly correlates with the incidence of late adverse cardiac events. We evaluated whether greater cardiac and, importantly, LAD dose sparing could be achieved using a newly introduced closed bore (O-ring gantry) linac with a double-stacked multileaf collimator (Varian Ethos) relative to conventional linacs.</div></div><div><h3>Methods and Materials</h3><div>Twenty patients with locally advanced non-small cell lung cancer previously treated with definitive chemoradiotherapy were retrospectively evaluated. Volumetric modulated arc therapy plans were retrospectively generated for the Ethos system using optimization criteria focused on reducing overall heart and LAD doses (Heart_Ethos). Plans were also reoptimized using the same optimization criteria on a conventional C-arm linac (Heart_TB). Investigational plans were compared with the original plans and with each other using standard dose-volume histogram metrics such as percentage (V) volume receiving a specific dose (x) in Gy (Vx) or mean dose (Dmean) in Gy.</div></div><div><h3>Results</h3><div>Statistically significant decreases existed between the Heart_Ethos and original plans for mean heart dose (11.3 vs 14.8 Gy; <em>P</em> &lt; .001) and V5, V30, and V50 (63.6% vs 75.2%; <em>P</em> &lt; .001, 7.1% vs 12.3%; <em>P</em> &lt; .001, 2.1% vs 2.9%; <em>P</em> = .03, respectively) and also for LAD mean dose (4.8 Gy vs 12.0 Gy [<em>P</em> &lt; .001]) and V15 (4.9% vs 21.5%; <em>P</em> &lt; .001). Compared with Heart_TB, Heart_Ethos plans had significantly less mean heart dose (11.6 vs 12.2 Gy; <em>P</em> = .006), and less heart V5 (64.4% vs 67.2%; <em>P</em> = .049) and V30 (7.7% vs 8.8%; <em>P</em> = .03), whereas other parameters were not significant. Optimal target coverage and other organs at risk constraints were maintained for all generated plans.</div></div><div><h3>Conclusions</h3><div>Heart_Ethos plans showed significant reduction in cardiac and LAD doses in comparison to the original plans while maintaining target and organ at risk goals. Our findings suggest that Ethos technology has the potential for better cardiac toxicity safety because Heart_Ethos plans were still able to reduce cardiac dose compared with Heart_TB plans.</div></div>","PeriodicalId":7390,"journal":{"name":"Advances in Radiation Oncology","volume":"10 6","pages":"Article 101779"},"PeriodicalIF":2.2,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143888277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In Regard to Niazi et al","authors":"Erkan Topkan MD ,&nbsp;Efsun Somay PhD ,&nbsp;Ugur Selek MD","doi":"10.1016/j.adro.2024.101707","DOIUrl":"10.1016/j.adro.2024.101707","url":null,"abstract":"","PeriodicalId":7390,"journal":{"name":"Advances in Radiation Oncology","volume":"10 4","pages":"Article 101707"},"PeriodicalIF":2.2,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143834115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advances in Radiation Oncology Top Downloaded Articles of 2024","authors":"Rachel B. Jimenez MD","doi":"10.1016/j.adro.2025.101749","DOIUrl":"10.1016/j.adro.2025.101749","url":null,"abstract":"","PeriodicalId":7390,"journal":{"name":"Advances in Radiation Oncology","volume":"10 4","pages":"Article 101749"},"PeriodicalIF":2.2,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143834114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Internal Target Volume Estimation for Liver Cancer Radiation Therapy Using an Ultra Quality 4-Dimensional Magnetic Resonance Imaging","authors":"Yen-Peng Liao Ph.D. ,&nbsp;Haonan Xiao Ph.D. ,&nbsp;Peilin Wang M.Sc. ,&nbsp;Tian Li Ph.D. ,&nbsp;Todd A. Aguilera M.D., Ph.D. ,&nbsp;Justin D. Visak Ph.D. ,&nbsp;Andrew R. Godley Ph.D. ,&nbsp;You Zhang Ph.D. ,&nbsp;Jing Cai Ph.D. ,&nbsp;Jie Deng Ph.D.","doi":"10.1016/j.adro.2025.101774","DOIUrl":"10.1016/j.adro.2025.101774","url":null,"abstract":"<div><h3>Purpose</h3><div>Accurate internal target volume (ITV) estimation is essential for effective and safe radiation therapy in liver cancer. This study evaluates the clinical value of an ultraquality 4-dimensional magnetic resonance imaging (UQ 4D-MRI) technique for ITV estimation.</div></div><div><h3>Methods and Materials</h3><div>The UQ 4D-MRI technique maps motion information from a low spatial resolution dynamic volumetric MRI onto a high-resolution 3-dimensional MRI used for radiation treatment planning. It was validated using a motion phantom and data from 13 patients with liver cancer. ITV generated from UQ 4D-MRI (ITV_4D) was compared with those obtained through isotropic expansions (ITV_{2 mm} and ITV_{5 mm}) and those measured using conventional 4D-computed tomography (computed tomography-based ITV, ITV_CT) for each patient.</div></div><div><h3>Results</h3><div>Phantom studies showed a displacement measurement difference of &lt;5% between UQ 4D-MRI and single-slice 2-dimensional cine MRI. In patient studies, the maximum superior-inferior displacements of the tumor on UQ 4D-MRI showed no significant difference compared with single-slice 2-dimensional cine imaging (<em>P</em> = .985). Computed tomography-based ITV showed no significant difference (<em>P</em> = .72) with ITV_4D, whereas ITV_{2 mm} and ITV_{5 mm} significantly overestimated the volume by 29.0% (<em>P</em> = .002) and 120.7% (<em>P</em> &lt; .001) compared with ITV_4D, respectively.</div></div><div><h3>Conclusions</h3><div>UQ 4D-MRI enables accurate motion assessment for liver tumors, facilitating precise ITV delineation for radiation treatment planning. Despite uncertainties from artificial intelligence-based delineation and variations in patients’ respiratory patterns, UQ 4D-MRI excels at capturing tumor motion trajectories, potentially improving treatment planning accuracy and reducing margins in liver cancer radiation therapy.</div></div>","PeriodicalId":7390,"journal":{"name":"Advances in Radiation Oncology","volume":"10 6","pages":"Article 101774"},"PeriodicalIF":2.2,"publicationDate":"2025-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143890550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In Silico Assessment of the Radiation Dose Range for Definitive Stereotactic Body Radiation Therapy of Primary Breast Cancer","authors":"I. Frank Ciernik MD ,&nbsp;Shubeen Singh MMed ,&nbsp;Akash K. Singh MS ,&nbsp;Philipp Goldschmidt MS ,&nbsp;Wilfried Budach MD ,&nbsp;Dirk Vordermark MD ,&nbsp;Jérôme Krayenbuehl PhD","doi":"10.1016/j.adro.2025.101775","DOIUrl":"10.1016/j.adro.2025.101775","url":null,"abstract":"<div><h3>Purpose</h3><div>The maximal dose for partial breast irradiation (PBI) with stereotactic body radiation therapy for definitive local therapy of nonmetastatic breast cancer has not been established. Here we evaluate the maximal achievable coverage of the planning target volume suitable for PBI without violating organs-at-risk constraints.</div></div><div><h3>Methods and Materials</h3><div>Planning computed tomography scans of 22 patients with pulmonary or cardiac risk factors and left-sided disease in prone and supine position (sp) were obtained. Plans for PBI in 5 fractions were generated according to the Guidelines of the American Society for Radiation Oncology. Maximum tolerated dose (MTD) was defined when the dose reached any constraint of a neighboring organ based on recommendations of the American Association for Physics in Medicine.</div></div><div><h3>Results</h3><div>Mean MTD was 45.9 ± 3.9 Gy (range, 38.8-53.9) in sp and 46.1 ±3.2 Gy (range, 37.3-53.9) in prone position (pp), respectively. The MTD was ≥44.3 Gy in sp and ≥44.8 Gy in pp in 95% of patients. Fat tissue was the dose limiting structure in 11 of 22 patients in sp and 15 of 22 in pp. D_max to the fat tissue reached 40.0 Gy (±3.3 Gy) in sp and pp. Skin was the dose limiting structure in 7 of 22 patients in sp and in 6 of 22 in pp. D_max to the skin was 30.5 Gy (±7.4 Gy) in sp and 31.0 Gy (±7.0 Gy) in pp (<em>P</em> = .8). Ribs were dose limiting in 4 of 22 patients in sp and in 1 of 22 in pp. D_max to the ribs was 31.4 Gy (±9.5 Gy) in sp and 21.4 Gy (±11.0 Gy) in pp (<em>P</em> &lt; .01). D_max to the intraventricular artery was 3.4 Gy (±3.1 Gy) in sp and 7.5 Gy (±5.7 Gy) in pp (<em>P</em> &lt; .01).</div></div><div><h3>Conclusions</h3><div>For definitive stereotactic body radiation therapy for early-stage breast cancer, we propose a dose escalation starting with 45 Gy in 5 fractions to be tested in a clinical trial. Prone position is advised for tumors close to the thoracic cage.</div></div>","PeriodicalId":7390,"journal":{"name":"Advances in Radiation Oncology","volume":"10 6","pages":"Article 101775"},"PeriodicalIF":2.2,"publicationDate":"2025-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143941622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Association of Circulating Inflammatory Biomarker Levels and Toxicity in Patients Undergoing Pelvic Radiation for Cancer: A Critical Review","authors":"Per Fessé PhD ,&nbsp;Per-Arne Svensson PhD ,&nbsp;Björn Zackrisson PhD ,&nbsp;Alexander Valdman PhD ,&nbsp;Per Fransson PhD ,&nbsp;Kjell Grankvist PhD ,&nbsp;Ingrid Kristensen PhD ,&nbsp;Ulrica Langegård PhD ,&nbsp;Emma Ohlsson-Nevo PhD ,&nbsp;Katarina Sjövall PhD ,&nbsp;Linda Åkeflo PhD ,&nbsp;Karin Ahlberg PhD","doi":"10.1016/j.adro.2025.101766","DOIUrl":"10.1016/j.adro.2025.101766","url":null,"abstract":"<div><h3>Purpose</h3><div>Radiation therapy (RT) causes tissue damage and inflammation. Because cytokines play a key role in such processes, their expression levels can be an indicator of cell and tissue toxicity. This critical review aims to explore whether levels of circulating inflammatory biomarkers in peripheral blood are associated with proton- or photon-based therapy in the pelvic area and how these levels vary over time. Further, we investigated whether these levels can be linked to radiation dose, the incidence of toxicity, and changes in toxicity over time.</div></div><div><h3>Methods and Materials</h3><div>A literature search was conducted in PubMed to find studies involving comparative cohorts of pelvic irradiated patients with cancer. Studies reporting on the association of markers in peripheral blood with inflammatory processes and/or toxicity were included.</div></div><div><h3>Results</h3><div>We found evidence of associations between changes in inflammatory cytokine levels and the total cumulative dose-volume together with RT-induced toxicity in patients with cancer treated with pelvic RT. Common patient-reported outcomes demonstrate an association between radiation toxicity (eg, genitourinary toxicity) and circulating inflammatory biomarker levels.</div></div><div><h3>Conclusions</h3><div>This review highlights that the total cumulative dose and irradiated tissue volume are the primary drivers of RT-induced biomarker expression, influencing both early and late toxicity outcomes. The diversity in RT techniques, total dose, and number of treatment sessions across studies likely contributes to the variation in observed results. Circulating cytokine and biomarker levels in the blood can provide valuable monitoring and predictive insights for patients undergoing proton- or photon-based RT of the pelvis. Biomarker analysis in the context of RT offers clinical value by enabling personalized treatment by helping predict which patients are at higher risk for certain toxicities, guiding clinicians in tailoring treatment, optimizing supportive care, and adjusting RT plans. This approach could improve patient outcomes and quality of life by reducing long-term complications from radiation exposure.</div></div>","PeriodicalId":7390,"journal":{"name":"Advances in Radiation Oncology","volume":"10 6","pages":"Article 101766"},"PeriodicalIF":2.2,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143854518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Re-irradiation With Carbon Ion Beams for Recurrent Adenoid Cystic Carcinoma of the Tongue Base: A Case Report","authors":"Eisuke Horigome MD, PhD ,&nbsp;Atsushi Musha DDS, PhD ,&nbsp;Nobuteru Kubo MD, PhD ,&nbsp;Naoko Okano MD, PhD ,&nbsp;Hidemasa Kawamura MD, PhD ,&nbsp;Tatsuya Ohno MD, PhD","doi":"10.1016/j.adro.2025.101761","DOIUrl":"10.1016/j.adro.2025.101761","url":null,"abstract":"","PeriodicalId":7390,"journal":{"name":"Advances in Radiation Oncology","volume":"10 5","pages":"Article 101761"},"PeriodicalIF":2.2,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143799444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Targeting Active Microglia Alleviates Distal Edge of Proton Radiation-induced Neural Damage","authors":"Keman Liao PhD ,&nbsp;Dan Ou PhD ,&nbsp;Mei Chen PhD ,&nbsp;Fei Xu MD ,&nbsp;Jianyi Zhao BS ,&nbsp;Li Zhou BS ,&nbsp;Ran Wu PhD ,&nbsp;Yingying Lin PhD ,&nbsp;Yibin Zhang BS ,&nbsp;Lu Cao PhD ,&nbsp;Jiayi Chen PhD","doi":"10.1016/j.adro.2025.101764","DOIUrl":"10.1016/j.adro.2025.101764","url":null,"abstract":"<div><h3>Purpose</h3><div>Proton therapy (PT) has distinct advantages in its ability to precisely target tumors while avoiding adjacent normal tissues. However, the distal edge effects of PT constrain its application. This study investigated the brain tissue response in the distal edge regions of protons and compared it with the effect of photons.</div></div><div><h3>Methods and Materials</h3><div>The occurrence of damage from photons and at the distal edge of protons was investigated in a murine model. Bragg peak treatment plans for murine models were optimized. Hematoxylin and eosin and immunofluorescence staining were performed along the distal margin. In addition, the approximate distance from the Bragg peak to the neuronal damage sites was calculated. Furthermore, a small-molecule inhibitor was studied for its ability to inhibit microglia activation.</div></div><div><h3>Results</h3><div>The distal edge brain injury murine model was successfully established. Reactive gliosis and granulovacuolar neuronal degeneration were observed in the right hemisphere of the brain in the proton irradiation group. Neuronal injuries were observed at multiple locations (the frontal lobe, thalamus, and cerebral cortex) along the distal border, but no injured neurons were detected along vertical photon irradiation exposed areas. Meanwhile, severe neural damage was seen with horizontal photon irradiation. At the distal edge of the Bragg peak (0.4633 ± 0.01856 cm), microglia with abnormal morphology accumulated. IBA1 and CD68 staining revealed activated microglia at the corresponding neuronal damage sites, indicating their involvement in irradiation-induced damage. Activated microglia were not observed with vertical photon irradiation, whereas many activated microglia were observed with horizontal photon irradiation. Moreover, asparagine endopeptidase inhibitors administered via intraperitoneal injection significantly reduced active microglia in the thalamus and cerebral cortex and alleviated brain damage.</div></div><div><h3>Conclusions</h3><div>This study demonstrated that proton radiation induces neuronal damage and accumulation of activated microglia at the distal edge. Targeting activated microglia may play a protective role in distal edge injury from radiation.</div></div>","PeriodicalId":7390,"journal":{"name":"Advances in Radiation Oncology","volume":"10 5","pages":"Article 101764"},"PeriodicalIF":2.2,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143816866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}