Journal of Applied Clinical Medical Physics最新文献

{"title":"Dosimetric impact of baseline shift plan in a magnetic resonance linear accelerator according to target motion and plan characteristics","authors":"Shohei Tanaka,&nbsp;Noriyuki Kadoya,&nbsp;Yoshiyuki Takahashi,&nbsp;Seiya Koga,&nbsp;Yoshiyuki Katsuta,&nbsp;Kazuhiro Arai,&nbsp;Taichi Hoshino,&nbsp;Yushan Xiao,&nbsp;Wingyi Lee,&nbsp;Noriyoshi Takahashi,&nbsp;Rei Umezawa,&nbsp;Keiichi Jingu","doi":"10.1002/acm2.70861","DOIUrl":"https://doi.org/10.1002/acm2.70861","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>In this study, the dosimetric effect of baseline shift (BLS) in a magnetic resonance linear accelerator was investigated and compared with adapt-to-position (ATP), adapt-to-shape (ATS), and an uncorrected plan without adaptation.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>In a simulation dataset consisting of 30 patients (10 prostate, 10 liver, 10 pancreatic), all structures were rigidly shifted by 1, 3, 5, and 10 mm separately in the superior–inferior and posterior directions, and four plans (ATS reoptimization, ATP reoptimization, BLS using the segment aperture morphing algorithm, and an uncorrected plan without adaptation) were generated for each shift condition. Planning target volume (PTV) coverage and PTV maximum dose (Dmax) were then compared. The dosimetric effects of BLS on the targets and organs at risk (OARs) under non-rigid anatomic changes were also evaluated using a clinical dataset based on magnetic resonance imaging acquired during treatment.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>In the simulation analysis of superior–inferior shifts, target coverage using BLS was comparable to that using ATS and ATP across all disease sites and improved compared with that using the uncorrected plan. For posterior shifts, target coverage remained comparable to that using ATS and ATP; however, BLS increased the PTV Dmax at all posterior shift magnitudes (1–10 mm) in prostate and pancreatic cases, with limited increases in liver cases. In the clinical dataset, OAR doses upon left–right or anterior–posterior displacement were greater using BLS than using ATP, ATS, and uncorrected plans in the prostate and pancreatic cases, with limited increases in the liver cases.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The dosimetric impact of BLS relies on motion direction and plan characteristics. BLS was stable for superior–inferior shifts, whereas posterior shifts may increase PTV hotspots and OAR doses. Therefore, clinical application of BLS should consider motion direction and plan design rather than applying a uniform strategy.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 11","pages":""},"PeriodicalIF":2.5,"publicationDate":"2026-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70861","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149222807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"General versus site specific quantile random forest models for virtual patient-specific quality assurance of VMAT plans","authors":"Naila Rahman,&nbsp;Greg Kaliel,&nbsp;Mark D'Souza,&nbsp;Dylan Yamabe Breitkreutz","doi":"10.1002/acm2.70854","DOIUrl":"10.1002/acm2.70854","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Background&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Modern radiotherapy techniques like volumetric-modulated arc therapy (VMAT) require labor-intensive patient-specific quality assurance (PSQA) measurements, which for busy clinics pose a substantial workflow burden. Most of these measurements simply confirm acceptable plans. This inefficiency has motivated the development of machine learning (ML) models for virtual PSQA to predict the gamma passing rate (GPR) and safely reduce the need for pre-treatment measurements. Plan complexity, often quantified by metrics like the small aperture score (SAS) and average leaf pair opening (ALPO), is a key predictor of PSQA outcome, and its relationship to GPR can vary across different treatment sites. Previous literature exploring ML for PSQA has focused on general models trained on a pooled dataset of all disease sites.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Purpose&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;To rigorously compare the predictive performance of a general ML model trained on a pooled dataset of multiple disease sites against site-specific ML models. We hypothesized that isolating plan complexity effects within each disease site would improve predictive accuracy, specifically by reducing false positives and improving specificity.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Methods&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;A total of 15 000 VMAT PSQA measurements (3%/3 mm global criteria, ArcCheck) from multiple disease sites were retrospectively collected. We developed and compared three general models—an XGBoost regressor (XGB), a standard random forest regressor (RFR), and a quantile random forest regressor (QRF)—using 14 plan complexity features as input. Five separate QRF models were also trained for the largest site groups (GI, GU, HN, Lung, and Prostate). For clinical decision-making, the QRF lower-quantile estimate was used as the predicted GPR to ensure a conservative safety margin. Model performance was evaluated using mean absolute error (MAE) and clinical metrics, including sensitivity (correctly identifying passes) and specificity (correctly identifying fails), across various pass/fail thresholds.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Results&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;The general QRF model achieved high accuracy (MAE: 0.92%), on par with measurement repeatability. The site-specific QRF models achieved prediction accuracy comparable to or better than the general model. Importantly, they substantially improved specificity and reduced false positives. For example, at the 95% threshold, the general model had an 8.8% false-positive rate, while the prostate-specific and GU-specific models produced (no false positives o","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2026-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70854","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149194082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development and validation of a pregnant phantom with adjustable fetal presentation for region-specific fetal radiation dose assessment during pelvic radiography","authors":"Yuta Matsunaga,&nbsp;Yumi Kataoka,&nbsp;Koichi Chida,&nbsp;Yasuki Asada","doi":"10.1002/acm2.70859","DOIUrl":"10.1002/acm2.70859","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Background&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Accurate assessment of fetal radiation dose during diagnostic X-ray examinations remains challenging because commercially available pregnancy phantoms do not adequately reproduce fetal anatomy or permit organ-specific dose measurements.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Purpose&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;The purpose of this study was to develop a pregnant phantom with adjustable fetal presentation and to evaluate its anatomical realism and applicability for fetal dose assessment during pelvic radiography.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Methods&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;The developed phantom comprised an anthropomorphic phantom, a whole-body fetal phantom, acrylic components, and water-filled plastic bags. The fetal phantom was fabricated using three-dimensional printing technology and incorporated bone-equivalent and soft-tissue-equivalent materials. Fetal presentations could be adjusted to cephalic or breech presentations by repositioning the fetal phantom within the abdominal phantom. Computed tomography (CT) images were acquired to measure CT numbers of the fetal brain, thorax, abdomen, pelvic bone, and surrounding water-filled regions. Absorbed doses were measured using real-time dosimeters placed at five locations in the fetal head and three locations in the fetal abdomen. Dose measurements were performed during pelvic radiography and compared with those obtained using a conventional homogeneous pregnancy phantom.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Results&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;The mean CT numbers of the fetal brain, thorax, abdomen, pelvic bone, and water-filled regions were 2.1, -0.8, -0.4, 323.8, and 1.6 HU, respectively. These values were within the expected ranges for soft tissue and bone and were comparable to those of a conventional homogeneous phantom. During pelvic radiography, the mean absorbed doses measured using the adjustable fetal-presentation phantom were 1.34 mGy in the fetal head and 0.07 mGy in the fetal abdomen for the cephalic presentation, and 0.05 mGy and 1.67 mGy, respectively, for the breech presentation. In comparison, the mean absorbed dose measured in the fetal region of the conventional homogeneous phantom was 2.05 mGy. The findings demonstrated substantial differences in regional fetal dose distribution according to fetal presentation. In particular, the fetal head dose in the cephalic presentation was lower than that measured using the conventional phantom. This difference may be partly attributable to attenuation by the fetal skull; however, the comparison should be interpreted with caution given differences in phantom geometry, int","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70859","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149181752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Automated linac downtime tracking across 4 radiation oncology clinics within a single hospital system utilizing statistical process control","authors":"Caroline E. Serafini,&nbsp;Matthew Thomas,&nbsp;Xiaofeng Yang,&nbsp;Pretesh Patel,&nbsp;Justin Roper,&nbsp;Maxine Washington,&nbsp;Anees Dhabaan,&nbsp;Hania Al-Hallaq","doi":"10.1002/acm2.70863","DOIUrl":"10.1002/acm2.70863","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Background&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Linear accelerator (linac) downtime disrupts clinical workflow and may delay patient treatment; however, downtime events are frequently undocumented or recorded in informal reporting systems. Data-driven approaches using routinely collected operational metrics may improve downtime surveillance and provide insight into system-level adaptation.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Purpose&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;This study aims to evaluate if statistical process control (SPC) methods can be applied to routine treatment and scheduling data from an oncology information system (OIS) to identify linac downtime events and characterize operational response across multiple radiation oncology clinics within a single hospital system.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Methods&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Daily machine-level operational data from 10 linacs across 4 clinics were analyzed over 29 months (January 2024–May 2026). Machine metrics included daily patient volume, cancellations, and operating hours. For each machine, rolling 45-day baseline means and standard deviations were computed, and SPC rules (± 3σ control limits and &gt; 10 cancellations / day) were applied to detect downtime days. SPC-flagged events were compared with email-based downtime event logs to calculate sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Downtime events were categorized by cause, and intra-hospital patient redistribution was assessed by identifying concurrent &gt; 4σ volume increases on alternate machines.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Results&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Over the 29-month study period, 138 downtime events were documented in downtime event logs. SPC identified 23 additional events exhibiting operational signatures consistent with downtime. Using reported events as the reference standard, SPC achieved sensitivity 0.70, specificity 0.99, PPV 0.79, and NPV 0.99. Downtime frequently resulted in compensatory increases in patient volume on alternate machines, with 41 transfer pairs identified across three hospitals. When the reported downtime cause was specified, machine mechanical causes accounted for the largest proportion (48%) of downtime events.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Conclusions&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;SPC applied to routinely collected operational data provides a scalable framework for automated linac downtime detection. Integration of automated monitoring with structured reporting may improve downtime surveillance and inform proactive operational planning in","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70863","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149181723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Omission of lateral isocenter shifts in robust optimization of proton therapy treatment plans for prostate cancer","authors":"Fionnbarr T O'Grady,&nbsp;Jackeline Castro,&nbsp;Daniel W Kim,&nbsp;Jiajin Fan,&nbsp;Peng Wang","doi":"10.1002/acm2.70833","DOIUrl":"10.1002/acm2.70833","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Proton therapy is routinely used to treat prostate cancer using bilaterally opposed beams and can achieve lower dose to nearby organs-at-risk (OARs) such as the bladder and rectum. Pencil beam scanning (PBS) proton therapy offers the most conformal treatment plans to best spare healthy tissue. Robust optimization is often utilized in planning PBS treatment to account for uncertainties in treatment delivery, such as misalignment of the isocenter, by evaluating the dose in perturbation scenarios in which the isocenter is translated. This process is effective but resource intensive and time consuming.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>To assess the feasibility of omitting lateral translations of the isocenter in robust optimization of pencil-beam scanning (PBS) proton therapy treatment plans for prostate cancer patients, utilizing parallel opposed lateral beams.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>The impact of isocenter shifts in the beam direction was studied systematically in a series of cube plans of varying field size and depth in water. In addition, the impact of omitting lateral isocenter shifts in robust optimization was analyzed retrospectively across sixteen clinical treatment plans, including plans with pelvic lymph nodes (LN) and a simultaneous integrated boost (SIB) delivered to the dominant intraprostatic lesion (DIL) or PET avid LNs. The impact on key dose-volume metrics for several OARs, as well as the results of robust evaluation and the difference in optimization time were recorded.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The plan comparison shows no significant difference in dose to any OAR or robust target coverage for any of the plans considered. The time required for a single optimization with fixed settings reduced by 24 min (22%) on average, with a maximum reduction of 129 min (43.1%).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Lateral isocenter shifts can be safely omitted in robust optimization of PBS proton therapy treatment plans for prostate patients, utilizing parallel opposed lateral beams, to achieve a significant reduction in optimization time, without increasing dose to OARs or sacrificing robust target coverage.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13662533/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149181980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Letter to the editor in response “Commissioning of a near real-time in vivo film dosimetry system”","authors":"Agnieszka Walewska,&nbsp;Paulina Wesołowska,&nbsp;Paweł Kukołowicz","doi":"10.1002/acm2.70847","DOIUrl":"10.1002/acm2.70847","url":null,"abstract":"<p>Dear Editor,</p><p>We read the article by Yunjie Yang et al., “Commissioning of near real-time in vivo dosimetry,” with great interest.<span>¹</span> The Pnt-Dos™ solution's particular value lies in its ability to significantly reduce the time between taking a measurement and obtaining a result. This is a major advantage of the Pnt-Dos™ in vivo dosimetry system. However, in Yang's paper, we found no information on how the reference dose is determined, that is the dose against which the in vivo measurement result is compared. When measurements are taken for patients who receive the full prescribed dose over their entire body—for example, in total body irradiation techniques or electron therapy—the reference dose is the prescribed dose itself. However, in the case of other radiotherapy techniques, particularly IMRT and VMAT, the dose at the surface differs significantly from the prescribed dose. We encountered this issue when preparing our film detector for in vivo measurements.<span>²</span> We resolved this issue by developing software that uses data retrieved from the treatment planning system (DICOM RT) to extract the dose from a depth of 3 mm, which is where the film is located within our detector. Tests carried out with our detector have shown that the software enables the precise determination of the reference dose for dynamic techniques. For the seven plans prepared using rotational techniques, the average discrepancy between the measured and calculated values was 1.4%, with a maximum discrepancy of 3.6%. We therefore adapted our build-cup cover for the Pnt-Dose™ system detectors, 3D-printed it, and repeated the previous measurements for our detector. The results confirmed the methodology's and software's suitability for in vivo dose measurement using Pnt-Dose™ on the body surface for dynamic techniques. We therefore adapted our build-up cover for the Pnt-Dose™ system detectors, 3D-printed it, and repeated the previous measurements carried out for our detector. The results confirmed the suitability of the methodology and software for in vivo dose measurement using the Pnt-Dose™ system on the body surface for dynamic techniques. For four VMAT plans, the average discrepancy between the measured and calculated values was 3.8%, with a maximum discrepancy of 6.3%. Integrating our proposed solution into the Pnt-Dose™ system would significantly expand its range of applications without compromising accuracy.</p>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70847","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149181946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimentally derived beam quality correction factors for PPC05 and razor nano ionization chambers in proton scanned beams based on graphite calorimetry","authors":"Nicolás Gómez-Fernández,&nbsp;Séverine Rossomme,&nbsp;Eloy González-García,&nbsp;Lies Verpoest,&nbsp;Faustino Gómez,&nbsp;Alejandro Mazal,&nbsp;Juan Antonio Vera-Sánchez,&nbsp;Diego M González Castaño","doi":"10.1002/acm2.70860","DOIUrl":"10.1002/acm2.70860","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Background&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Ionization chamber based reference dosimetry of proton beam requires the use of beam quality correction factors which are obtained experimentally or by Monte Carlo simulation and are available to users in codes of practice and other publications.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Purpose&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;The aim of this work is to determine experimental proton beam quality correction factors, &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;k&lt;/mi&gt;\u0000 &lt;mi&gt;Q&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;annotation&gt;${{k}_Q}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, for two ionization chambers using a portable graphite calorimeter: the IBA reference-class PPC05 chamber and the IBA non reference-class Razor Nano chamber, using a portable graphite calorimeter.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Methods&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Measurements were performed in scanned clinical proton beams at two clinical centers. Absorbed dose to graphite was determined using a recently developed portable graphite calorimeter. The conversion factors for the absorbed dose to water determination were obtained by Monte Carlo simulations. Finally, the experimental &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;k&lt;/mi&gt;\u0000 &lt;mi&gt;Q&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;annotation&gt;${{k}_Q}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; factors were obtained by comparing ionization chamber readings with the calorimeter, measured using the same conditions, in terms of absorbed dose to water.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Results&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;For the IBA PPC05 chamber, the experimental values agreed with recommended values tabulated in TRS-398 (rev. 1) within the combined experimental uncertainty for the three residual ranges of 3.4, 13.3 and 27.7 g·cm&lt;sup&gt;−2&lt;/sup&gt;. For Razor Nano chamber, &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;k&lt;/mi&gt;\u0000 &lt;mi&gt;Q&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;annotation&gt;${{k}_Q}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; values of 1.009 and 1.011 for residual ranges of 13.3 and 27.7 g·cm&lt;sup&gt;−2&lt;/sup&gt; have been determined. No recommended values are provided in TRS_398 (rev. 1). The overall budget yielded a combined standard uncertainty in the experimental &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 ","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13662534/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149181885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of online dose-guided adaptive fractionation for intact prostate radiotherapy","authors":"Gevork S. Gevorkyan,&nbsp;Libing Zhu,&nbsp;Riley C. Tegtmeier,&nbsp;Diego Santos Toesca,&nbsp;Weiguo Lu,&nbsp;Mingli Chen,&nbsp;Yi Rong,&nbsp;Quan Chen","doi":"10.1002/acm2.70865","DOIUrl":"10.1002/acm2.70865","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Dose-guided adaptive fractionation (DGAF) was proposed as a simpler alternative of adaptive radiation therapy, using organ variation simulation for proof of concept. However, its dosimetric benefit using actual daily anatomy changes in prostate cancer patients remains unclear.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>The purpose of this study was to retrospectively evaluate the dosimetric benefit and potential risk of DGAF for prostate cancer patients treated with moderately hypofractionated radiotherapy and stereotactic body radiotherapy using daily cone-beam CT.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Patients assessed in this study were treated with moderately hypofractionated radiotherapy (MHRT, <i>n</i> = 11, 244 total fractions) and stereotactic body radiotherapy (SBRT, <i>n</i> = 11, 55 total fractions). The optimizer algorithm computed the desired fractional dose based on favorable or unfavorable anatomical conditions derived from daily imaging, quantified by the sparing factor threshold (μ) and spread (σ). Three methods of estimating subsequent fractionation schemes were explored. The assessment relative to patient-specific probabilities observed post-treatment includes the cohort-based probability (CBP) approach, the individual-based probability (IBP) approach, and the hybrid approach that begins as CBP and transitions to the IBP after a certain number of fractions. The benefits/risks of DGAF were assessed by calculating the equivalent dose in 2 Gy fractions (EQD2) for both the CTV and the rectum in comparison to regular fractionation.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>DGAF demonstrated potential dosimetric benefits for intact prostate patients. The average and standard deviation of the sparing factor was 0.51 ± 0.11 for MHRT patients and 0.42 ± 0.04 for SBRT patients treated with endorectal-balloon. The hybrid approach for estimating the patients’ threshold μ and spread σ outperformed other approaches assessed for both cohorts. The highest dosimetric benefit was retrospectively seen in MHRT patients where a hybrid approach were used, showing equal or decreased D15% EQD2.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>DGAF demonstrated considerable rectum sparing potential, and the benefits increased with longer fractionation and advanced approaches toward subsequent fraction estimation.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70865","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149181737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Machine learning predictors of post-radiotherapy cardiotoxicity in a Latin American breast cancer cohort: Clinical risk factors outperform cardiac dosimetry","authors":"Víctor Aguirre-Bravo,&nbsp;Rodrigo El Far,&nbsp;María Herrera Ruiz,&nbsp;Sophia Gálvez Santelices,&nbsp;Pablo Munoz-Schuffenegger,&nbsp;Tomás Merino,&nbsp;Sergio Diez Domingo,&nbsp;Marcelo E. Andia","doi":"10.1002/acm2.70862","DOIUrl":"10.1002/acm2.70862","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Background&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Most evidence on post-radiotherapy cardiotoxicity (CDT) derives from Global North cohorts, and the relative contribution of baseline clinical risk versus cardiac dosimetry remains poorly characterized in Latin American populations.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Purpose&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;To examine, in a Chilean breast cancer cohort, whether baseline clinical risk factors or cardiac dose-volume metrics better predict post-RT cardiac events, using supervised and unsupervised learning.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Methods&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Retrospective cohort of 42 breast cancer patients treated with thoracic radiotherapy (RT, median heart dose 2.6 Gy; median follow-up 84.4 months). CDT was defined per CTCAE v5.0 (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mo&gt;≥&lt;/mo&gt;\u0000 &lt;annotation&gt;$ge$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; Grade 1), excluding Grade 1 events coded under the non-specific term &lt;i&gt;“Cardiac disorders – Other, specify”&lt;/i&gt;, which on review were incidental imaging findings. Dose-volume histogram (DVH) parameters from seven cardiac substructures were extracted. Firth penalized logistic regression was used for prediction, principal component analysis (PCA) and kernel PCA for exploratory clustering, and bootstrap 0.632+ for optimism correction. The 2023 American Heart Association (AHA) PREVENT score was evaluated post hoc.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Results&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Ten patients (23.8%) developed CDT and 16 (38.1%) experienced cardiovascular events. No DVH differences were found between CDT+ and CDT− groups across any cardiac structure (all &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;p&lt;/mi&gt;\u0000 &lt;mo&gt;&gt;&lt;/mo&gt;\u0000 &lt;mn&gt;0.05&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$p &gt; 0.05$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;), although the design is powered only for large effects. By contrast, IMRT delivered significantly higher cardiac doses than 3D-CRT across multiple substructures, without a differential CDT rate. Pre-existing cardiovascular disease was the strongest predictor (crude OR = 6.50, &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;p&lt;/mi&gt;\u0000 &lt;mo&gt;=&lt;/mo&gt;\u0000 &lt;mn&gt;0.020&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$p=0.020$&lt;/annotation&gt;\u0000 ","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70862","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149182017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correction to: “Probabilistic quality assurance of biopsy DVH thresholds in HDR prostate brachytherapy under localization uncertainty”","authors":"","doi":"10.1002/acm2.70852","DOIUrl":"10.1002/acm2.70852","url":null,"abstract":"<p>Muscat M, Crook J, Jirasek A, Andrews J, Becker N. Probabilistic quality assurance of biopsy DVH thresholds in HDR prostate brachytherapy under localization uncertainty. <i>J Appl Clin Med Phys</i>. 2026;27:e70660. https://doi.org/10.1002/acm2.70660</p><p>A bibliographic correction is required for Reference 31. At the time of submission of the original article, the referenced companion manuscript had not yet been published and was therefore cited using its pre-publication title and status. The article has since been published with a revised title and final publication details.</p>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13662530/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149181804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}