Physics and Imaging in Radiation Oncology最新文献

{"title":"Partial adaptation for online-adaptive proton therapy triggered by during-delivery treatment verification: Feasibility study on prostate cancer treatments","authors":"Virginia Gambetta ,&nbsp;Victoria Pieta ,&nbsp;Jonathan Berthold ,&nbsp;Tobias Hölscher ,&nbsp;Albin Fredriksson ,&nbsp;Christian Richter ,&nbsp;Kristin Stützer","doi":"10.1016/j.phro.2025.100755","DOIUrl":"10.1016/j.phro.2025.100755","url":null,"abstract":"<div><h3>Background and Purpose</h3><div>Online treatment verification during proton therapy delivery may detect deviations due to anatomical changes occurring along the treatment course and trigger immediate intervention, if necessary. We investigated the potential of partial plan adaptation in two-field prostate cancer treatments as a solution for online-adaptive proton therapy (OAPT) after the detection of relevant treatment deviations during the first field delivery.</div></div><div><h3>Materials and Methods</h3><div>In a retrospective study, ten fractions from eight prostate cancer patients with prompt gamma imaging (PGI) detected treatment deviations, which were confirmed on respective in-room control computed tomography (cCT) scans, were considered. For each cCT, a dose-mimicking-based robust partial adaptation reoptimized the second field by considering the suboptimal dose delivery of the first non-adapted, PGI-monitored field. The results were compared to the non-adapted scenario and upfront full adaptation (both fields) in terms of achievable target coverage (prescription: 48 Gy/60 Gy to low-risk/high-risk target) and organ-at-risk (OAR) sparing.</div></div><div><h3>Results</h3><div>Partially adapted plans showed comparable target coverage (median <em>D</em>_98%: 99.9%/98.0% for low-/high-risk target) to fully adapted plans (100.3%/98.7%) and were superior to non-adapted plans (98.7%/94.5%). Achievable OAR sparing was patient-specific depending on the proximity to the target region, but within clinical goals for the partially and fully adapted plans.</div></div><div><h3>Conclusions</h3><div>Partial adaptation triggered mid-delivery of a fraction can still generate plans of comparable conformity to full adaptation, even in the case of plans with only two, opposing fields. A verification-triggered OAPT may therefore become an alternative to upfront OAPT, saving time and imaging dose in fractions without relevant anatomy changes.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"34 ","pages":"Article 100755"},"PeriodicalIF":3.4,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143739446","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":"Ultra-low field magnetic resonance breast imaging in prone and seated positions for radiation therapy","authors":"Friderike K. Longarino ,&nbsp;Sheng Shen ,&nbsp;Neha Koonjoo ,&nbsp;Torben P.P. Hornung ,&nbsp;Rachel B. Jimenez ,&nbsp;Elie K. Mehanna ,&nbsp;John T. Burge ,&nbsp;Zoelle Wilson ,&nbsp;Kathryn E. Keenan ,&nbsp;Thomas R. Bortfeld ,&nbsp;Matthew S. Rosen ,&nbsp;Susu Yan","doi":"10.1016/j.phro.2025.100758","DOIUrl":"10.1016/j.phro.2025.100758","url":null,"abstract":"<div><h3>Background &amp; purpose</h3><div>The aim of this first-in-human study was to investigate the potential of ultra-low field (ULF) magnetic resonance imaging (MRI) at 6.5<!--> <!-->mT for breast imaging in healthy female participants in prone and seated positions for radiation therapy, especially compact proton therapy systems.</div></div><div><h3>Materials &amp; methods</h3><div>An experimental setup for breast imaging in prone and seated positions utilizing an ULF MRI scanner and a conical RF coil was developed. ULF MR images of the left breast of ten healthy women were acquired in prone and seated positions using a 3D balanced steady-state free precession sequence without the use of contrast agents. The visibility of the breast outline, chest wall, and cardiac silhouette in prone and seated position ULF breast MR images was evaluated by two radiation oncologists (ROs) and two radiation therapists (RTTs), respectively.</div></div><div><h3>Results</h3><div>ULF breast MRI obtained at 6.5<!--> <!-->mT can show breast outline, chest wall, and cardiac silhouette in prone and seated positions. ULF prone/seated images were found to be acceptable by the ROs (RTTs) for treatment planning (setup) purposes in 100%/95% (95%/85%) of cases for breast outline visibility, in 70%/50% (75%/70%) of cases for chest wall visibility, and in 65%/65% (0%/10%) of cases for cardiac silhouette visibility.</div></div><div><h3>Conclusions</h3><div>This proof-of-concept study demonstrated that breast imaging is feasible in prone and seated positions utilizing ULF MRI and partially suitable for treatment planning and setup in proton therapy. Yet an increased spatio-temporal resolution is required for applications to MRI-guided proton therapy. ULF MRI may enable position monitoring and adaptive treatment procedures in radiation therapy.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"34 ","pages":"Article 100758"},"PeriodicalIF":3.4,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143725298","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":"A systematic review of tumour position reproducibility and stability in breath-hold for radiation therapy of the upper abdomen","authors":"Briana Farrugia ,&nbsp;Kerryn Brown ,&nbsp;Kellie Knight ,&nbsp;Caroline Wright","doi":"10.1016/j.phro.2025.100751","DOIUrl":"10.1016/j.phro.2025.100751","url":null,"abstract":"<div><h3>Background and purpose</h3><div>Upper abdominal malignancies are relatively rare, and although surgery is considered the primary treatment option, radiation therapy has an emerging role in the management of liver, pancreas, kidney and adrenal gland tumours. Furthermore, stereotactic radiation therapy for the management of upper abdominal metastases is an expanding clinical indication. Breath-hold is one respiratory motion management strategy used in upper abdominal radiation therapy, and the reproducibility, and stability of breath-hold is critical for overall treatment accuracy.</div></div><div><h3>Materials and methods</h3><div>A systematic review of the literature was conducted in Medline, Embase and Cochrane databases with keyword and vocabulary terms related to radiation therapy, breath-hold and upper abdominal tumours.</div></div><div><h3>Results</h3><div>Following screening against the selection criteria, 41 studies were included. Breath-hold reproducibility was the most commonly reported outcome and exhale breath-hold was the most common type. Studies were either prospective or retrospective cohort studies, and the mean sample size was 19 participants. The risk of bias of each included study was assessed, and the mean quality assessment score for included studies was 90 % (77–100 %). Median exhale breath-hold cranio-caudal inter-fraction reproducibility was 0.6 mm, (IQR 0.3–1.6 mm), compared to inspiratory breath-hold 0.0 mm (IQR −0.6–2.97 mm). Stability measurements were ≤3 mm in 71 % of studies, irrespective of breath-hold type.</div></div><div><h3>Discussion</h3><div>Formulating institutional protocols for best clinical practice regarding breath-hold for upper abdominal tumours is challenging, given the significant variation in practices, interventions and definitions observed in the literature. Further investigation to individualise breath-hold strategies and safety margins is warranted.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"34 ","pages":"Article 100751"},"PeriodicalIF":3.4,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143715190","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":"Dose calculation accuracy of clinical radiotherapy plans using next generation cone beam computed tomography imaging technology","authors":"Peter R. Martin ,&nbsp;Amanda Cherpak ,&nbsp;R. Lee MacDonald ,&nbsp;Abigail Yashayaeva ,&nbsp;David McAloney ,&nbsp;Natasha McMaster ,&nbsp;Kenny Zhan ,&nbsp;Slawa Cwajna ,&nbsp;Nikhilesh Patil ,&nbsp;Hannah M. Dahn ,&nbsp;James L. Robar","doi":"10.1016/j.phro.2025.100756","DOIUrl":"10.1016/j.phro.2025.100756","url":null,"abstract":"<div><h3>Background and purpose</h3><div>Next generation cone beam computed tomography (CBCT) technology has shown improved Hounsfield unit accuracy over standard CBCT, and comparable to that of fan beam CT simulators (CTsim), potentially allowing direct dose calculation on CBCT. In this study, we evaluated the dose calculation accuracy of clinical treatment plans calculated using this technology, compared with standard CBCT.</div></div><div><h3>Materials and methods</h3><div>Thirty subjects with thoracic or upper abdominal cancer were imaged on CTsim, standard CBCT and next generation CBCT, and treated using breath hold techniques. Both CBCT image sets were rigidly registered to CTsim, and clinical treatment plans were forward calculated on all images. 3D Gamma analysis was used to evaluate CBCT dose distributions relative to CTsim, and DVH analysis compared PTV and OAR dose metrics.</div></div><div><h3>Results</h3><div>The median (±IQR) 3 %/3 mm gamma pass rate was 96.7 ± 3.1 % for next generation CBCT and 93.3 ± 14.0 % for standard CBCT. Next generation CBCT gamma scores were statistically significantly higher than standard CBCT for all gamma criteria. Median DVH metrics were within ± 2.3 % and ± 2.7 % of the corresponding values from CTsim, for next generation and standard CBCT respectively. Standard CBCT showed an underestimation of ipsilateral lung dose for breast subjects, while next generation CBCT did not.</div></div><div><h3>Conclusions</h3><div>Next generation CBCT allows for good average DVH agreement with CTsim, and improved dose calculation accuracy over standard CBCT across 3D dose distributions. While further clinical investigations are warranted, this technology may allow for the use of CBCT in direct-dose calculation in adaptive radiotherapy.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"34 ","pages":"Article 100756"},"PeriodicalIF":3.4,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143695917","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":"Investigation of changes in planning target volume and regression probability of rectal boost using in-silico cone-beam computed tomography-guided online-adaptive radiotherapy","authors":"Julien Pierrard ,&nbsp;David Dechambre ,&nbsp;Geneviève Van Ooteghem","doi":"10.1016/j.phro.2025.100757","DOIUrl":"10.1016/j.phro.2025.100757","url":null,"abstract":"<div><h3>Background and purpose</h3><div>Radiotherapy boost to the primary tumour may enable organ preservation in locally advanced rectal cancer (LARC). This study evaluated cone-beam computed tomography (CBCT)-guided online-adaptive radiotherapy (ART) to reduce rectal boost planning target volume (PTV_Boost) margins and allow dose escalation.</div></div><div><h3>Materials and methods</h3><div>Eleven LARC patients were included in this <em>in silico</em> study. Population-based PTV_Boost margins were computed for non-adaptive and online-ART using van Herk’s formalism. Dose/volume results were compared between: non-adaptive RT with a 25 x 2.16 Gy boost (Non-ART_54Gy), ART with a 25 x 2.16 Gy boost (ART_54Gy), and ART with an escalated boost of 25 x 2.4 Gy (ART_60Gy). Tumour regression probability was compared between each plan using a dose–response model.</div></div><div><h3>Results</h3><div>PTV_Boost margins for non-adaptive vs. online-ART were 14.2 vs. 3.3 mm in the antero-posterior, 5.0 vs. 3.2 mm in the left–right, and 12.3 vs. 8.7 mm in the supero-inferior axes. PTV_Boost and pelvic lymph node PTV coverage (V95%) were significantly improved with ART_54Gy and ART_60Gy compared to Non-ART_54Gy (p &lt; 0.001). High-priority organ-at-risk constraints (priority 1&amp;2) were violated in 26.8 % of cases for Non-ART_54Gy, 21.2 % of cases for ART_54Gy, and 20.8 % of cases for ART_60Gy. Tumour regression probability was superior for ART_60Gy (20.8 %) compared to ART_54Gy (17.0 %, p &lt; 0.001) and Non-ART_54Gy (16.9 %, p &lt; 0.001).</div></div><div><h3>Conclusions</h3><div>Online-ART significantly reduce rectal boost PTV margin. It allows better target volume coverage with a similar risk of radiation-induced toxicities, even when escalating the dose. Therefore, online-ART should be considered to perform dose-escalation in LARC patients with the objective of organ preservation.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"34 ","pages":"Article 100757"},"PeriodicalIF":3.4,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143725297","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":"Magnetic resonance imaging in glioblastoma radiotherapy − beyond treatment adaptation","authors":"Viktor R. Paczona ,&nbsp;Zoltán Végváry ,&nbsp;Gyöngyi Kelemen ,&nbsp;Ágnes Dobi ,&nbsp;Emőke Borzási ,&nbsp;Linda Varga ,&nbsp;Adrienne Cserháti ,&nbsp;Angéla Csomor ,&nbsp;Bence Radics ,&nbsp;Sándor Dósa ,&nbsp;Márton Balázsfi ,&nbsp;Emese Fodor ,&nbsp;Ferenc Borzák ,&nbsp;Árpád Puskás ,&nbsp;Zoltán Varga ,&nbsp;Judit Oláh ,&nbsp;Katalin Hideghéty","doi":"10.1016/j.phro.2025.100754","DOIUrl":"10.1016/j.phro.2025.100754","url":null,"abstract":"<div><h3>Background and Purpose</h3><div>The treatment of glioblastoma remains a challenging task for modern radiation oncology. Adaptive radiotherapy potentially improves local control and reduces toxicity to healthy brain tissue. The purpose of the study was to examine the safety of adaptive radiotherapy in glioblastoma, using a margin-reduction approach based on an interim magnetic resonance image (MRI). Furthermore, it aimed to identify radiomorphological features that may correlate with disease outcome.</div></div><div><h3>Materials and Methods</h3><div>108 glioblastoma patients receiving standard chemoradiotherapy underwent repeated MRI after 40 Gy. The images were compared to the pre-radiotherapy MRI, based on the following criteria: midline shift, perifocal edema, contrast enhancement, ventricular compression, new lesion outside the radiation field, gross tumor volume (GTV) and planning target volume (PTV) size. Target volumes were adjusted by taking into consideration the new intracranial conditions and the remaining 20 Gy was delivered. Statistical analysis consisted of the comparison of the radiomorphological features to overall and progression free survival.</div></div><div><h3>Results</h3><div>Increased or unchanged contrast enhancement (HR: 2.11 and 1.18 consecutively) and ventricular compression (HR: 13.58 and 2.53) on the interim MRI resulted in significantly poorer survival. GTV size (initial: 61.4 [3.8–170.9], adapted: 45.3 [0–206.8] cm3) reduction (absolute: −16.2 [-115.3–115.5] cm3, relative: −24.5 [-100–258.9] %) also had demonstrable impact on survival. Changes in PTV, however, did not significantly correlate with survival.</div></div><div><h3>Conclusions</h3><div>By reducing PTV based on an interim MRI, we achieved substantial sparing of critical normal tissues, without compromising survival. The established evaluation categories can facilitate the systematic review of interim MRI findings.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"34 ","pages":"Article 100754"},"PeriodicalIF":3.4,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143725370","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":"A planning approach for online adaptive proton therapy to cope with cone beam computed tomography inaccuracies","authors":"Michelle Oud ,&nbsp;Sebastiaan Breedveld ,&nbsp;Kelvin Ng Wei Siang ,&nbsp;Roberto Cassetta ,&nbsp;Steven Habraken ,&nbsp;Zoltán Perkó ,&nbsp;Ben Heijmen ,&nbsp;Mischa Hoogeman","doi":"10.1016/j.phro.2025.100752","DOIUrl":"10.1016/j.phro.2025.100752","url":null,"abstract":"<div><h3>Background and purpose</h3><div>In online-adaptive proton therapy planning based on cone beam computed tomography (CBCT), CT number errors can pose challenges. We propose an approach for coping with CT number uncertainties by increasing range robustness settings (RRS) in online-adaptive planning. This was compared to our trigger-based offline (TB-Offline) adaptive approach, and to daily replanning using in-room CT-on-rails (CTOR).</div></div><div><h3>Material and methods</h3><div>For 23 head-and-neck cancer patients, a CTOR and CBCT were acquired in a single fraction. CTOR contours were copied rigidly onto the CBCT. CBCT-based plans were generated with 3, 6, 8, 10, and 12 % RRS, each with 1 mm setup-RS, followed by a forward dose calculation on the reference CTOR. This was compared to dose distributions from our TB-Offline approach (3 mm/3% SRS/RRS), also recomputed on the CTOR. Coverage (voxelwise-minimum) of the primary clinical target volume (CTV₇₀₀₀) and elective lymph nodes (CTV₅₄₂₅) and grade ≥ II normal tissue complication probabilities were compared between strategies.</div></div><div><h3>Results</h3><div>When going from RRS = 3 % to RRS = 10 %, the population 90th percentiles of CTV₅₄₂₅ V_94% improved from 89.6 % to 96.4 %, and CTV₇₀₀₀ V_94% from 92.8 % to 96.4 %. Substantial coverage loss (V_94%&lt;95 %) with CBCT-based online adaptive and RRS = 10 % was observed in 1/23 evaluated patients for CTV₇₀₀₀ and 2/23 for CTV₅₄₂₅. This was an improvement compared to 3/23 and 4/23 with TB-Offline. Moreover, for RRS = 10 % the average risk of xerostomia improved by 2.4 percentage point compared to TB-Offline.</div></div><div><h3>Conclusions</h3><div>Robust optimization with increased range robustness settings effectively mitigated dose degradation from CT number errors in CBCT-based online-adaptive proton therapy.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"34 ","pages":"Article 100752"},"PeriodicalIF":3.4,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143685850","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":"Recent innovations in offline and online Magnetic Resonance Imaging guided radiation oncology","authors":"Luca Boldrini,&nbsp;Daniela Thorwarth,&nbsp;Lorenzo Placidi","doi":"10.1016/j.phro.2025.100753","DOIUrl":"10.1016/j.phro.2025.100753","url":null,"abstract":"","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"34 ","pages":"Article 100753"},"PeriodicalIF":3.4,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143698153","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":"Accuracy of manufacturer integrated quality control for helical radiotherapy","authors":"Frederik Crop,&nbsp;Maeva Bocquet,&nbsp;Clémence Kirie,&nbsp;Julien Laffarguette,&nbsp;Romain Cayez,&nbsp;Mohamed Tahar Ladjimi,&nbsp;Erwann Rault,&nbsp;Pauline Comte,&nbsp;Ludovic Vanquin,&nbsp;Thomas Lacornerie,&nbsp;Camille Decoene","doi":"10.1016/j.phro.2025.100750","DOIUrl":"10.1016/j.phro.2025.100750","url":null,"abstract":"<div><h3>Background and Purpose</h3><div>Manufacturer-integrated quality control (MIQC) systems are often used but not considered standard in codes-of-practice (COP), such as TG148/306 or NCS27, for helical radiotherapy. MIQC can lead to false positive results and generally lacks external validation. Energy quality control (QC) conditions are defined in COPs, manuals, or MIQC using various field sizes, phantoms, and indicators assuming equal response functions to energy changes. This study investigated the accuracy of MIQC for helical radiotherapy.</div></div><div><h3>Materials and Methods</h3><div>A clinical helical treatment unit was detuned in terms of energy, dose rate, field width, and air pressure. The reproducibility/precision and response/trueness of MIQC, conventional QC methods, and patient-specific quality assurance were evaluated. Monte Carlo calculations were performed to identify differences in responses of depth dose ratios DD10/1.5, DD20/1.5, DD20/10, Tissue-Phantom Ratio TPR20/10, and ratio to max DD10(x) for various field sizes and phantoms.</div></div><div><h3>Results</h3><div>The accuracy of MIQC for underlying causes was determined; precision was often excellent, but trueness required proportionality correction: e.g., 1 % DD10(x, 5 × 10 cm², H₂O) showed almost equal response to TPR20/10, DD20/10 and exit detector flatness in most conditions but a 2 % DD20/1.5(1x40cm²) and step-wedge MIQC response. Exit detector output constancy was not significantly sensitive to field size changes but was sensitive to energy and dose rates. A guiding table containing response functions and reproducibility coefficients was established.</div></div><div><h3>Conclusions</h3><div>The MIQC metrological accuracy assessment can be used to define action/tolerance limits for COPs as well as to easily analyze out-of-bound results in routine practice.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"34 ","pages":"Article 100750"},"PeriodicalIF":3.4,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143696040","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":"Physics-based data augmentation for improved training of cone-beam computed tomography auto-segmentation of the female pelvis","authors":"Yvonne J.M. de Hond ,&nbsp;Paul M.A. van Haaren ,&nbsp;An-Sofie E. Verrijssen ,&nbsp;Rob H.N. Tijssen ,&nbsp;Coen W. Hurkmans","doi":"10.1016/j.phro.2025.100744","DOIUrl":"10.1016/j.phro.2025.100744","url":null,"abstract":"<div><h3>Background and Purpose</h3><div>Labeling cone-beam computed tomography (CBCT) images is challenging due to poor image quality. Training auto-segmentation models without labelled data often involves deep-learning to generate synthetic CBCTs (sCBCT) from planning CTs (pCT), which can result in anatomical mismatches and inaccurate labels. To prevent this issue, this study assesses an auto-segmentation model for female pelvic CBCT scans exclusively trained on delineated pCTs, which were transformed into sCBCT using a physics-driven approach.</div></div><div><h3>Materials and Methods</h3><div>To replicate CBCT noise and artefacts, a physics-driven sCBCT (Ph-sCBCT) was synthesized from pCT images using water-phantom CBCT scans. A 3D nn-UNet model was trained for auto-segmentation of cervical cancer CBCTs using Ph-sCBCT images with pCT contours. This study included female pelvic patients: 63 for training, 16 for validation and 20 each for testing on Ph-sCBCTs and clinical CBCTs. Auto-segmentations of bladder, rectum and clinical target volume (CTV) were evaluated using Dice Similarity Coefficient (DSC) and 95th percentile Hausdorff Distance (HD95). Initial evaluation occurred on Ph-sCBCTs before testing generalizability on clinical CBCTs.</div></div><div><h3>Results</h3><div>The model auto-segmentation performed well on Ph-sCBCT images and generalized well to clinical CBCTs, yielding median DSC’s of 0.96 and 0.94 for the bladder, 0.88 and 0.81 for the rectum, and 0.89 and 0.82 for the CTV on Ph-sCBCT and clinical CBCT, respectively. Median HD95′s for the CTV were 5 mm on Ph-sCBCT and 7 mm on clinical CBCT.</div></div><div><h3>Conclusions</h3><div>This study demonstrates the successful training of auto-segmentation model for female pelvic CBCT images, without necessarily delineating CBCTs manually.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"34 ","pages":"Article 100744"},"PeriodicalIF":3.4,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143609812","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}