Journal of Medical Imaging and Radiation Sciences最新文献

{"title":"Automatic field-of-view planning for magnetic resonance shoulder imaging using Deep Learning","authors":"Anton Sheahan Quinsten ,&nbsp;Simon Joshua Hornisch ,&nbsp;Marcel Gratz ,&nbsp;Mathias Holtkamp ,&nbsp;Michael Forsting ,&nbsp;Kai Nassenstein ,&nbsp;Lale Umutlu ,&nbsp;Armin Lühr ,&nbsp;Jens Kleesiek ,&nbsp;Moon-Sung Kim ,&nbsp;Aydin Demircioğlu","doi":"10.1016/j.jmir.2026.102197","DOIUrl":"10.1016/j.jmir.2026.102197","url":null,"abstract":"<div><h3>Introduction</h3><div>Accurate prescription of oblique coronal and oblique sagittal field of views (FOV) is essential for diagnostic shoulder MRI. Manual planning is radiographer-dependent, time-consuming, and subject to inter- and intra-operator variability, leading to inconsistent image quality and incomplete coverage. Although deep learning (DL) has advanced automated scan planning in non-oblique planes, oblique shoulder prescriptions remain underexplored; an automated DL approach could standardize FOV prescription, reduce operator dependence, and improve reproducibility and workflow without compromising diagnostic quality.</div></div><div><h3>Methods</h3><div>In this retrospective multicenter study, 575 shoulder MRI examinations (2019–2025) from four sites were included. Sites A (n=151) and B (n=220) were used for training; testing was performed on sites C (n=61), and D (n=143). A two-stage pipeline was implemented using five oriented bounding box (OBB) variants of YOLOv11 (n, s, m, l, x): Stage 1 performed slice selection; Stage 2 performed FOV prescription. Performance was evaluated against radiographers' prescriptions using mean absolute slice difference (MASD, slices), intersection over union (IoU), and mean absolute angle difference (MAAD, degrees). Clinical utility was assessed by three raters.</div></div><div><h3>Results</h3><div>The YOLOv11-OBB-l model achieved the lowest MASD for Stage 1 (1.016±0.153 slices). For Stage 2, YOLOv11-OBB-x performed best (coronal IoU, 0.847±0.003; sagittal IoU, 0.852±0.007; MAAD, 3.259±0.190°). During testing across each site, MASD ranged from 0.700±0.837 to 1.192±2.550 slices; MAAD from 2.811±2.348 to 4.396±7.158°; coronal IoU from 0.800±0.092 to 0.872±0.065; and sagittal IoU from 0.824±0.111 to 0.887±0.047. Mean clinical utility was 97.2%. Performance was noninferior to interrater variability across all sites and metrics.</div></div><div><h3>Conclusion</h3><div>DL–based automated FOV prescription for shoulder MRI achieves performance comparable to radiographers, generalizes across institutions, and demonstrates high clinical utility.</div></div>","PeriodicalId":46420,"journal":{"name":"Journal of Medical Imaging and Radiation Sciences","volume":"57 3","pages":"Article 102197"},"PeriodicalIF":2.0,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192513","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":"MR guided uncertainty quantification of tumour motion in open face masks versus closed face masks in head and neck radiotherapy","authors":"James Tallon ,&nbsp;Claire Nelder ,&nbsp;Benedict Dobby ,&nbsp;Alice Greenwood-Wilson ,&nbsp;Rachael Bailey ,&nbsp;Michael Dubec ,&nbsp;Andrew McPartlin ,&nbsp;John Gaffney ,&nbsp;Marcel van Herk ,&nbsp;Ananya Choudhury ,&nbsp;Cynthia L. Eccles","doi":"10.1016/j.jmir.2026.102196","DOIUrl":"10.1016/j.jmir.2026.102196","url":null,"abstract":"<div><h3>Purpose</h3><div>To assess positional reproducibility and tumour motion using standard of care (SoC) masks versus open face masks (OF) on an MR Linac (MRL) in head and neck (H&amp;N) cancer radiotherapy (RT).</div></div><div><h3>Materials/Methods</h3><div>Four H&amp;N cancer patients, oral cavity (<em>n</em> = 1), and oropharynx (<em>n</em> = 3) undergoing RT (60–66 Gy in 20–30 #) consented to an ethics approved imaging study. Patients underwent three MRI sessions on a 1.5 T MR Linac (Elekta, Sweden) that included six dynamic T₂-weighted Fast Spin Echo 3D images acquired over an 8-minute period during the first, middle and final week of RT. Patients were imaged to compare the OF mask to SoC mask. Each dynamic image (<em>n</em> = 6) was registered to the first image, to assess tumour motion using rigid registration performed by three observers. A clip box was used to establish rotations and translations in the tumour region of interest (ROI). Intra and inter-fraction tumour motion were calculated over the three sessions.</div></div><div><h3>Results</h3><div>Intra-fraction tumour motion was greater in X (pitch) and Z (yaw) rotations when wearing an OF mask compared to SoC, however displacements were within institutional tolerances. Translations were similar for both immobilisation devices.</div></div><div><h3>Conclusions</h3><div>A small intra fraction tumour motion increase was seen with the OF mask, but all displacements were within institutional tolerances. Larger cohort studies are needed to improve strength of this work.</div></div>","PeriodicalId":46420,"journal":{"name":"Journal of Medical Imaging and Radiation Sciences","volume":"57 3","pages":"Article 102196"},"PeriodicalIF":2.0,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192482","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":"Radiographers' perspectives on interactions with patients exhibiting cognitive impairment and dementia during magnetic resonance imaging examinations","authors":"Sarah Hanley ,&nbsp;Mark F. McEntee ,&nbsp;Peter Murphy ,&nbsp;Rena Young ,&nbsp;Andrew England ,&nbsp;Salman Mohammed Albeshan ,&nbsp;Mohammadreza Elhaie","doi":"10.1016/j.jmir.2026.102187","DOIUrl":"10.1016/j.jmir.2026.102187","url":null,"abstract":"<div><h3>Background</h3><div>Dementia and cognitive impairment are prevalent among older adults and present significant challenges during magnetic resonance imaging (MRI) examinations, particularly regarding compliance, communication, and procedural adaptations. Despite MRI’s central role in diagnosing neurodegenerative disorders, limited research has examined radiographers’ experiences with this vulnerable patient group.</div></div><div><h3>Objective</h3><div>To quantitatively investigate radiographers’ interactions with patients exhibiting dementia or cognitive impairment during MRI examinations, focusing on procedural barriers, adaptations, and implications for patient care.</div></div><div><h3>Methods</h3><div>A prospective cross-sectional study was conducted in the MRI department of a tertiary public hospital in Ireland. Eight state-registered MRI radiographers completed structured questionnaires (<em>n</em> = 20 patient encounters) immediately following examinations of patients with documented or observed cognitive impairment or dementia. Descriptive statistics and cross-tabulations were used to analyze procedural outcomes, communication effectiveness, and modifications implemented.</div></div><div><h3>Results</h3><div>Patients had a mean age of 77 years (range 65–89). Cognitive status was undocumented on referral in 85% of cases and most often identified via ward communication (50%). Only 25% of patients fully comprehended instructions, with 75% unable to cooperate. Procedural modifications were required in 30% of cases, primarily reduced scan duration and motion correction. Examination disruptions included incompleteness (25%) and abortion (15%). Patient distress was observed before (10%), during (30%), and after (15%) scanning. Radiographers employed strategies such as increased communication and interaction, though no carers were present during scans.</div></div><div><h3>Conclusion</h3><div>Radiographers face substantial challenges in managing MRI examinations for patients with dementia or cognitive impairment, including poor referral documentation, communication barriers, and frequent procedural disruptions. Findings highlight the need for dementia-friendly protocols, environmental adaptations, carer involvement, and targeted radiographer training to optimize diagnostic quality and patient-centered care.</div></div>","PeriodicalId":46420,"journal":{"name":"Journal of Medical Imaging and Radiation Sciences","volume":"57 3","pages":"Article 102187"},"PeriodicalIF":2.0,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146135722","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":"Explainability-informed benchmarking of two deep learning models for organ-at-risk segmentation in MR-guided adaptive radiotherapy","authors":"H. Sekkat ,&nbsp;A. Khallouqi ,&nbsp;Y. Hammouga ,&nbsp;A. Halimi ,&nbsp;O. El mouden ,&nbsp;A. Bannan ,&nbsp;Y. Berrada ,&nbsp;O. El rhazouani","doi":"10.1016/j.jmir.2026.102200","DOIUrl":"10.1016/j.jmir.2026.102200","url":null,"abstract":"<div><h3>Introduction/Background</h3><div>Segmentation of gastrointestinal (GI) organs-at-risk (OARs) is a critical yet time-consuming step in MR-guided adaptive radiotherapy (MRgRT), with manual delineation prone to inter- and intra-observer variability. While deep learning approaches have shown promise, their clinical adoption requires not only accuracy but also interpretability and reliability. This study benchmarks two widely used convolutional architectures, U-Net and Residual U-Net (ResUNet), for abdominal OAR segmentation, with an emphasis on explainability-oriented quantitative analysis.</div></div><div><h3>Methods</h3><div>An anonymized abdominal MRI dataset was used to train and evaluate U-Net and ResUNet using a 5-fold stratified group cross-validation strategy. Segmentation performance was assessed using the Dice Similarity Coefficient (DSC), Intersection-over-Union (IoU), and the 95th percentile Hausdorff Distance (HD95). Explainability was investigated using Gradient-weighted Class Activation Mapping (Grad-CAM) computed from the final convolutional layer of each network. To enable objective analysis beyond qualitative visualization, Grad-CAM activation maps were quantified using numerical localization metrics relative to ground-truth organ masks, including in-organ energy ratio, boundary energy ratio, pointing accuracy, activation Dice coefficient, centroid distance and activation entropy. Grad-CAM metrics were aggregated across gastrointestinal organs and averaged over the five validation folds.</div></div><div><h3>Results</h3><div>Both architectures demonstrated comparable segmentation performance across organs, with no statistically significant differences across evaluated metrics. Grad-CAM analysis showed similar region-level attention patterns, with in-organ activation ratios of 71.4 ± 8.6% for U-Net and 66.2 ± 9.1% for ResUNet, boundary energy ratios of 24.1 ± 4.9% and 21.8 ± 5.2%, respectively, and pointing accuracies exceeding 70% for both models. Uncertainty analysis based on inter-fold variability and boundary error dispersion indicated comparable stability and bounded worst-case behavior.</div></div><div><h3>Discussion/Conclusion</h3><div>By integrating performance, uncertainty and explainability quantitative indicators, this study provides an informed benchmarking of two deep learning models for abdominal OAR segmentation. The results suggest that both U-Net and ResUNet exhibit stable and interpretable behavior under the evaluated configurations, supporting their potential use in MR-guided adaptive radiotherapy workflows where reliability and clinical trust are essential.</div></div>","PeriodicalId":46420,"journal":{"name":"Journal of Medical Imaging and Radiation Sciences","volume":"57 3","pages":"Article 102200"},"PeriodicalIF":2.0,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192514","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":"Embedding clinical education skills in pre-registration radiography programmes: An evaluation of a novel approach utilising assessment","authors":"Christine J. Heales,&nbsp;Demelza J. Green","doi":"10.1016/j.jmir.2026.102194","DOIUrl":"10.1016/j.jmir.2026.102194","url":null,"abstract":"<div><h3>Introduction</h3><div>Clinical teaching is increasingly recognised as a core responsibility for all radiographers within the United Kingdom, as reflected in the Health and Care Professions Council Standards of Proficiency and the College of Radiographers’ Education and Careers Framework. However, workload pressures, curriculum unfamiliarity, and limited confidence present barriers to effective clinical teaching. To address this, a clinical education assessment was, novelly, introduced in the final year of BSc and MSc pre-registration diagnostic radiography apprenticeship programmes The aim of this Educational Perspective is to describe the evaluation of this innovative initiative aimed at supporting the development of clinical education skills in pre-registration radiography learners.</div></div><div><h3>Method</h3><div>The assessment method required learners to prepare a lesson plan and deliver a 30-minute workplace teaching session, assessed as pass/fail with structured feedback. MSc learners undertook an additional practical component to differentiate the academic level from the BSc programme The graded element comprised a reflective account encompassing planning, theoretical underpinnings, delivery, and feedback received, marked by academic staff. Evaluation of the novel assessment utilised mid- and end-of-module feedback and External Examiner commentary under the authors’ Higher Education Institute’s delegated review process.</div></div><div><h3>Results</h3><div>Mid-module feedback (51%, (<em>n</em> = 18) response rate) indicated learners felt more confident in clinical teaching, valued assessor feedback, and reported improved skills in delivering constructive feedback. They also highlighted increased confidence in public speaking and lesson delivery, though requested further support in lesson planning and assessment guidance. End-of-module responses (40%, <em>n</em> = 14) echoed these themes, with some nervousness around being assessed noted. External Examiner feedback affirmed the novelty and value of the initiative.</div></div><div><h3>Discussion</h3><div>This evaluation suggests that embedding clinical education assessments within pre-registration curricula fosters self-perception of learner preparedness for future teaching roles. Further research should explore the longer-term impact post-qualification.</div></div>","PeriodicalId":46420,"journal":{"name":"Journal of Medical Imaging and Radiation Sciences","volume":"57 3","pages":"Article 102194"},"PeriodicalIF":2.0,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146183950","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":"Message from the Editor-in-Chief","authors":"Tara Rosewall PhD, FCAMRT","doi":"10.1016/j.jmir.2026.102188","DOIUrl":"10.1016/j.jmir.2026.102188","url":null,"abstract":"","PeriodicalId":46420,"journal":{"name":"Journal of Medical Imaging and Radiation Sciences","volume":"57 2","pages":"Article 102188"},"PeriodicalIF":2.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147350056","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":"Can daily online imaging be avoided in head and neck cancer patients treated with Halcyon E: A retrospective analysis of a large number of daily imaging-based corrections","authors":"Animesh Saha ,&nbsp;Mani Tirthankar Das,&nbsp;Ajoy Banik,&nbsp;Saubhik Ghosh,&nbsp;Prakash Das,&nbsp;Sujata Sarkar","doi":"10.1016/j.jmir.2025.102162","DOIUrl":"10.1016/j.jmir.2025.102162","url":null,"abstract":"<div><h3>Introductions</h3><div>Integrated daily online image guidance is the default practice in Halcyon E; which costs extra time and additional imaging dose. This retrospective study aimed to evaluate the feasibility of less than daily imaging with off-line no action level (NAL) correction protocol in head and neck cancer patients.</div></div><div><h3>Materials and methods</h3><div>Set-up data of 2969 fractions of 100 head and neck cancer patients were analysed. Using summary data, we calculated the systematic error (∑), random error (δ), PTV margin separately for each of the three axes, as well as the error vector. We then simulated two NAL offline correction protocol where set-up errors of the first three (protocol Fraction-3) or five fractions (protocol Fraction-5) were averaged and implemented for the remaining fractions. The residual errors in each axis for these fractions were determined together with the residual ∑ and δ. PTV margins using the van Herk formula (PTV= 2.5∑ + 0.7δ) were generated based on the uncorrected errors as well as for the residual errors after NAL-based Fraction-3 and Fraction-5 protocols. For each protocol, we tabulated the number of fractions where the residual errors were more than 5 mm. We also assessed whether errors tended to differ based on intent of treatment and anatomical subsite.</div></div><div><h3>Results</h3><div>In our study, uncorrected set-up errors resulted in systematic and random errors of ∑x,y,z of 1.6. 1.6 and 1.7 mm and σx,y,z of 1.6, 1.7 and 1.7 mm with a required PTV margin in x,y,z axes of 5.1, 5.2 and 5.4 mm. Therefore, without image guidance and correction, 5 mm margins would not be adequate. Protocol Fraction-3 resulted in a significant reduction in the residual systematic error to ∑x,y,z of 1.0, 1.2 and 1.3 mm, whereas random errors remained unchanged. Protocol fraction -5 resulted in a further small improvement in systematic errors to ∑x,y,z of 0.9, 0.8, 1.1 mm. PTV margin was within 5mm in both protocol and proportion of fraction with &gt;5mm residual shift was small. PTV margin for Fraction-3 protocol was &gt;5 mm for Larynx-Hypopharynx subsite but within 5 mm for other subgroups.</div></div><div><h3>Conclusion</h3><div>NAL offline imaging implementing average shifts of first five fraction seems possible in this retrospective study. This resource sparing IGRT protocol may result in a significant reduction in time and imaging dose. Patients with larynx/hypopharynx subsites and those treated with Radical intent may require more careful evaluation and daily online matching.</div></div>","PeriodicalId":46420,"journal":{"name":"Journal of Medical Imaging and Radiation Sciences","volume":"57 2","pages":"Article 102162"},"PeriodicalIF":2.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145624942","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":"SPLIT PRIT: A Novel Clearing Agent-Independent Approach for Pretargeted Alpha Therapy with 212Pb","authors":"Sofia Frost ,&nbsp;Alexander Haas ,&nbsp;Alexandre Pichard ,&nbsp;Annabelle Mouchotte ,&nbsp;Agnès Colmont ,&nbsp;Julien Torgue ,&nbsp;Sara Colombetti ,&nbsp;Christian Klein ,&nbsp;Pablo Umana","doi":"10.1016/j.jmir.2026.102246","DOIUrl":"10.1016/j.jmir.2026.102246","url":null,"abstract":"&lt;div&gt;&lt;h3&gt;Introduction&lt;/h3&gt;&lt;div&gt;Pretargeted radioimmunotherapy (PRIT) aims to improve the therapeutic index of systemic radiotherapy, typically involving a tumour-targeting bispecific antibody (BsAb) followed by a rapidly clearing small radiolabelled molecule. This strategy minimises healthy tissue exposure while increasing the absorbed dose to tumours. Rapid radioligand pharmacokinetics are particularly critical for efficacy and tolerability when using short-lived radionuclides like 212Pb (t1/2 = 10.6 h). While earlier PRIT regimens required an intermediate clearing agent to neutralise circulating BsAb, efforts are now focusing on developing clearing agent-independent approaches to decrease logistical complexity and mitigate safety risks.&lt;/div&gt;&lt;/div&gt;&lt;div&gt;&lt;h3&gt;Objectives&lt;/h3&gt;&lt;div&gt;We developed a novel two-step, clearing agent-independent PRIT regimen for carcinoembryonic antigen (CEA)-positive tumours. This regimen involves a complementary SeParated v-domains LInkage Technology (SPLIT) antibody pair and a 212Pb radioligand. We asse&lt;/div&gt;&lt;/div&gt;&lt;div&gt;&lt;h3&gt;Materials and Methods&lt;/h3&gt;&lt;div&gt;Two human SPLIT antibodies were developed that bind specifically and bivalently to human CEA, each fused to one half of a split high-affinity sub-pM 1,4,7,10-Tetrakis(carbamoylmethyl)1,4,7,10-tetraazacyclododecane (DOTAM) antibody variable region fragment: one antibody with the variable heavy (VH) and the other with the variable light (VL) domain. Bound to CEA on the cell surface, these split VH/VL domains assemble to form the active binding site for the subsequently administered therapeutic radioligand, 212Pb-DOTAM, capturing it significantly more efficiently than circulating SPLIT antibodies. To assess the functionality of this approach, we treated mice bearing subcutaneous CEA-expressing BxPC3 xenografts with the two pretargeting SPLIT antibodies, followed 7 days later by 212Pb-DOTAM. Another group of mice received a CEA-DOTAM BsAb, followed 7 days later by a dextran-based clearing agent to neutralise circulating BsAb, and then 212Pb-DOTAM after 24 hours. The two- and three-step CEA-PRIT regimens were compared for 212Pb biodistribution, tumour growth inhibition, and tolerability after three treatment cycles of 0.74 MBq (20 μCi).&lt;/div&gt;&lt;/div&gt;&lt;div&gt;&lt;h3&gt;Results&lt;/h3&gt;&lt;div&gt;Both CEA-PRIT regimens achieved significant and comparable tumour growth delay. Only mild transient body weight loss was observed in both groups, confirming comparable tolerability. Excellent 212Pb tumour specificity was confirmed in both regimens. Tumour uptake for the two-step PRIT was 25–30% IA/g at 24 h p.i., compared to 36–45% IA/g for the three-step PRIT. Importantly, blood and kidney retention remained low for both regimens (&lt;0.5% IA/g and &lt;2 %IA/g, respectively).&lt;/div&gt;&lt;/div&gt;&lt;div&gt;&lt;h3&gt;Conclusion&lt;/h3&gt;&lt;div&gt;The novel two-step CEA-targeted SPLIT PRIT approach demonstrated therapeutic efficacy and tolerability comparable to the three-step regimen. Biodistribution data confirmed the preferential retent","PeriodicalId":46420,"journal":{"name":"Journal of Medical Imaging and Radiation Sciences","volume":"57 2","pages":"Article 102246"},"PeriodicalIF":2.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147578593","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":"Combining Radioimmunotherapy with Immune Checkpoint Inhibitors to Enhance Colorectal Cancer Treatment Efficacy","authors":"Tongshuo Hu,&nbsp;Rubin Jiao,&nbsp;Kevin John Harvey Allen,&nbsp;Connor Frank,&nbsp;Mackenzie E Malo,&nbsp;Ekaterina Dadachova","doi":"10.1016/j.jmir.2026.102242","DOIUrl":"10.1016/j.jmir.2026.102242","url":null,"abstract":"&lt;div&gt;&lt;h3&gt;Introduction&lt;/h3&gt;&lt;div&gt;Colorectal cancer (CRC) has become the fourth leading cause of cancer-related death worldwide, accounting for 10% of all newly diagnosed cancers. Immunotherapy with immune checkpoint inhibitors (ICIs) is an effective cancer treatment to restore the T cell activity by blocking inhibitory pathways such as PD-1/PD-L1 and CTLA-4. However, ICIs show limited efficacy treating CRCs due to tumor-infiltrating regulatory T cells (ti-Treg), which suppress T cell activity in the tumor microenvironment (TME). By targeting ti-Tregs with radioimmunotherapy (RIT), a targeted radionuclide therapy that combines the specificity of monoclonal antibodies with the cytotoxic potential of therapeutic radionuclides, we aim to eliminate ti-Tregs, and thus improve CRC therapeutic outcomes. Utilizing C-C chemokine receptor type 8 (CCR8) as a biomarker of ti-Tregs would specifically direct our RIT.&lt;/div&gt;&lt;/div&gt;&lt;div&gt;&lt;h3&gt;Objectives&lt;/h3&gt;&lt;div&gt;The objective is to optimize the CCR8-targeted RIT in CRC murine models by determining how different antibody forms, intact IgG vs Fab, impact tumor and non-specific organ uptake. We are able to utilize 111Indium (111In) as a surrogate radioisotope for t&lt;/div&gt;&lt;/div&gt;&lt;div&gt;&lt;h3&gt;Materials and Methods&lt;/h3&gt;&lt;div&gt;2.5% papain was added to intact anti-CCR8 IgG and incubated at 37°C for 20h. Both Fab and Fc were detectable after the papain digestion, therefore protein G MagBeads (10μl:25μg) were used to remove Fc and clarify the mixture. Intact IgG and Fab were conjugated to DOTA (a bifunctional chelating agent) and radiolabeled with 111In. Isotope uptake was compared for IgG and Fab in an in vivo MicroSPECT/CT imaging study performed in the syngeneic CT26-BALB/c and MC38-C57BL/6 mouse models. Mice were injected with 3.7 MBq of either [111In]In-α-CCR8-DOTA-IgG or [111In]In-α-CCR8-DOTA-Fab. MicroSPECT/CT imaging time course was conducted between a 2-72hrs post injection. Mice were humanely sacrificed at 72h and a full ex vivo biodistribution was performed.&lt;/div&gt;&lt;/div&gt;&lt;div&gt;&lt;h3&gt;Results&lt;/h3&gt;&lt;div&gt;While both [111In]In-α-CCR8-DOTA-IgG and [111In]In-α-CCR8-DOTA-Fab showed high uptake in the tumor, the [111In]In-α-CCR8-DOTA-IgG demonstrated increased tumor uptake relative to the Fab starting at the 24h timepoint. [111In]In-α-CCR8-DOTA-Fab group also exhibited significantly higher uptake in kidney compared to [111In]In-α-CCR8-DOTA-IgG group, this was observed in both models.&lt;/div&gt;&lt;/div&gt;&lt;div&gt;&lt;h3&gt;Conclusion&lt;/h3&gt;&lt;div&gt;From the SPECT/CT imaging and biodistribution, we can conclude that both [111In]In-α-CCR8-DOTA-IgG and [111In]In-α-CCR8-DOTA-Fab demonstrated high tumor uptake in both colorectal cancer models, which could lead to effective tumor killing in radioimmunotherapy. However, the high kidney uptake of [111In]In-α-CCR8-DOTA-Fab which could result in nephrotoxicity during treatment, excluding this as a viable therapy option. Future pre-clinical RIT studies utilizing 225Ac and 177Lu will be completed with intact anti-CCR8 IgG.&lt;/div&gt;","PeriodicalId":46420,"journal":{"name":"Journal of Medical Imaging and Radiation Sciences","volume":"57 2","pages":"Article 102242"},"PeriodicalIF":2.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147578597","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":"Evaluation of in vivo relative biological effectiveness (RBE) of alpha and Auger/conversion-electron therapies in prostate cancer xenograft models","authors":"Robin Peter ,&nbsp;Anil P. Bidkar ,&nbsp;Kondapa Naidu Bobba ,&nbsp;Juan Antonio Camara Serrano ,&nbsp;Veronica Steri ,&nbsp;Scott Bidlingmaier ,&nbsp;Bin Liu ,&nbsp;Robert R. Flavell ,&nbsp;Youngho Seo","doi":"10.1016/j.jmir.2026.102284","DOIUrl":"10.1016/j.jmir.2026.102284","url":null,"abstract":"&lt;div&gt;&lt;h3&gt;Introduction&lt;/h3&gt;&lt;div&gt;Alpha-particles are more cytotoxic per unit absorbed dose than photons or beta particles because their high linear energy transfer (LET, often &gt;100 keV/μm) causes dense ionization and DNA double-strand breaks. However, the limited consensus on the relative biological effectiveness (RBE) of alpha-particle radiopharmaceuticals creates uncertainty. This complicates the cross-comparison of absorbed doses between internal and external radiation modalities, motivating direct in vivo RBE estimation. Even less data exist on the efficacy of Auger and conversion electrons, which are also of therapeutic interest due to their extremely short range and intermediate LET (1-20 keV/μm).&lt;/div&gt;&lt;/div&gt;&lt;div&gt;&lt;h3&gt;Objectives&lt;/h3&gt;&lt;div&gt;Our goal was to directly estimate RBEs for therapeutic radiopharmaceuticals, 225Ac-DOTA-YS5 and 134Ce/La -PSMA-617 in vivo, in comparison to the reference biological effect by external x-ray beam to the tumors in murine prostate cancer models.&lt;/div&gt;&lt;/div&gt;&lt;div&gt;&lt;h3&gt;Materials and Methods&lt;/h3&gt;&lt;div&gt;Two prior radiopharmaceutical therapy studies (225Ac-DOTA-YS5 and 134Ce-PSMA-617) in human prostate cancer (22Rv1 and PC3-PIP) xenograft models in mice were used to estimate in vivo RBE with respect to 320 kVp collimated external beam therapy in 2-Gy daily fractions. For each irradiation mode, transplanted tumors were administered a control dosage (saline or 0 Gy) and at least two levels of dose escalation or injected activity, then measured for tumor growth during the treatment and follow-up. Tumor dosimetry was conducted with ex vivo 225Ac-progeny gamma counting or 134Ce/La-PET imaging and OLINDA/EXM sphere models, respectively. Tumor growth delay (1-6 mo.) and mean tumor burden (10-90% reduction) were assessed to estimate RBE in each model.&lt;/div&gt;&lt;/div&gt;&lt;div&gt;&lt;h3&gt;Results&lt;/h3&gt;&lt;div&gt;The in vivo RBE value for 225Ac-DOTA-YS5 was between 2-3 for all endpoints calculated, mostly contribution from all four alphas in the decay chain. Calculations for 134Ce-PSMA-617 showed greater endpoint variance, with RBE values between 0.1 and 0.7, but were dominated by contributions from dose-delivering positrons from 134La that is generated in vivo from the 134Ce decay with the same half-life (3.16 d) at a secular equilibrium.&lt;/div&gt;&lt;/div&gt;&lt;div&gt;&lt;h3&gt;Conclusion&lt;/h3&gt;&lt;div&gt;The estimated in vivo RBE of 225Ac-DOTA-YS5 was lower than the commonly cited alpha-particle RBE value of 5, suggesting that some of the perceived efficacy from 225Ac is attributable to the significant absorbed doses imparted by its multiple-alpha decay chain, not solely its high biological effectiveness of alpha particles. This result may suggest that in vivo factors such as microscale heterogeneity or chelator instability caused by the nuclear recoil effect resulting in daughter radionuclides redistribution may reduce the biological efficacy of alpha particles emitted from 225Ac. The estimated RBE of 0.1–0.7 for 134Ce/La-PSMA-617 suggests the potential of therapeutic positro","PeriodicalId":46420,"journal":{"name":"Journal of Medical Imaging and Radiation Sciences","volume":"57 2","pages":"Article 102284"},"PeriodicalIF":2.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147578710","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}