Journal of Applied Clinical Medical Physics最新文献

{"title":"Patient-size based dose optimization in projection radiography examinations: A BMI-guided approach","authors":"Sachith Welarathna, Sivakumar Velautham, Sivananthan Sarasanandarajah","doi":"10.1002/acm2.70191","DOIUrl":"https://doi.org/10.1002/acm2.70191","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>The increasing prevalence of obesity poses challenges for dose optimization in projection radiography due to greater anatomical thickness in overweight and obese patients worldwide. Diagnostic reference levels (DRLs) alone may not adequately account for variations in body habitus, potentially leading to suboptimal patient protection. This study aimed to explore benchmark doses (BMDs) based on patient body mass index (BMI) for projection radiography examinations of major anatomical regions in Sri Lanka, providing a complementary approach for dose optimization alongside DRLs.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>This prospective study included 1989 adult patients (≥18 years) undergoing abdomen anteroposterior (AP), chest posteroanterior (PA), kidney–ureter–bladder (KUB) AP, lumbar spine AP, lumbar spine lateral (LAT), and pelvis AP examinations at six major tertiary care hospitals. For each examination, patient demographics (age, weight, height, and BMI) and exposure parameters (kilovoltage peak [kVp] and tube current-exposure time product [mAs]) were recorded, and the patient doses in terms of kerma-area product (P<sub>KA</sub>) were measured using a P<sub>KA</sub> meter. DRLs (achievable doses) were proposed at the median of the median P<sub>KA</sub> distribution across hospitals for a standard-sized patient group (58 ± 20 kg). For BMI-based BMDs, patients were classified into four standard BMI categories: underweight, normal weight, overweight, and obese. The median P<sub>KA</sub> distributions across hospitals were used to formulate BMI-based BMDs, which were then compared with the proposed DRLs for the standard-sized patient group.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The results showed a progressive increase in BMI-based BMDs across BMI categories for all examinations studied. BMI-based BMDs (in Gy.cm<sup>2</sup>) for underweight, normal weight, overweight, and obese patients were as follows: 1.46, 1.94, 2.88, 3.00 (abdomen AP); 0.17, 0.21, 0.22, 0.25 (chest PA); 1.70, 1.76, 2.30, 3.60 (KUB AP); 1.00, 1.03, 1.29, 1.48 (lumbar spine AP); 1.94, 2.09, 2.57, 2.56 (lumbar spine LAT); and 0.60, 1.85, 1.86, 2.24 (pelvis AP). Compared to normal weight patients, underweight patients exhibited percentage reductions in BMI-based BMDs of 24.7%, 3.4%, 2.9%, 7.1%, 4.5%, and 67.6% for abdomen AP, KUB AP, lumbar spine AP, lumbar spine LAT, chest PA, and pelvis AP, respectively. Conversely, overweight patients demonstrated percentage increases of 48.5%, 30.7%, 25.2%, 23.0%, 4.8%, and 0.5% across the same examinations, while obese patients showed increases of 54.6%, 104.5%, 51.5%, 22.5%, 19.0%, and 21.1%, re","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 7","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70191","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144624747","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":"CT Imaging-based radiomics predicts the pain relief of Strontium-89 in treating tumor-induced bone metastases","authors":"Danzhou Fang,&nbsp;Yaofeng Xiao,&nbsp;Shunhao Zhou,&nbsp;Feng Shi,&nbsp;Yuwei Xia,&nbsp;Gengbiao Yuan,&nbsp;Xiaojiao Xiang","doi":"10.1002/acm2.70189","DOIUrl":"https://doi.org/10.1002/acm2.70189","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Bone metastasis is a common complication in advanced malignancies, often resulting in severe pain and reduced quality of life. Radiopharmaceuticals like Strontium-89 (⁸⁹Sr) are commonly used for palliative treatment to alleviate bone pain associated with metastases. This study explores the potential of radiomics analysis in predicting the effectiveness of ⁸⁹Sr treatment for pain relief in patients with bone metastases.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>The study analyzed clinical and imaging data from 146 patients with bone metastases, specifically focusing on two types of lesions: osteolytic and osteoblastic. Pain relief was assessed by the step of the WHO pain ladder required for pain relief, along with a reduction in opioid dosage, indicating effective pain management. Based on exploratory analysis, a Bagging Decision Tree machine learning model was selected for outcome prediction in osteolytic lesions, while the XGBoost model was utilized for osteoblastic lesions. Both models leveraged radiomics features extracted from these lesions to improve predictive accuracy. Model performance was evaluated using the area under the receiver operating characteristic curve (AUC), along with sensitivity, specificity, accuracy, and calibration curves.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The pain relief rate for osteolytic metastases was 58.33%, and for osteoblastic metastases, it was 62.16%. The Bagging Decision Tree model achieved an AUC of 0.991 in the training set and 0.889 in the test set for osteolytic lesions. For osteoblastic lesions, the XGBoost model yielded robust results, with an AUC of 0.970 in the training set and 0.958 in the test set.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>This study shows promise in predicting pain relief outcomes of ⁸⁹Sr treatment in patients with bone metastases.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 7","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70189","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144624748","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":"Medical physicist should be a planner in the treatment planning process","authors":"Dongxu Wang,&nbsp;Douglas E. Prah,&nbsp;Yi Rong","doi":"10.1002/acm2.70185","DOIUrl":"https://doi.org/10.1002/acm2.70185","url":null,"abstract":"&lt;p&gt;In the United States, both medical physicists and medical dosimetrists play essential roles in radiotherapy. Since its inception, the profession of medical dosimetry has focused primarily on the creation of treatment plans and related clinical tasks. In contrast, the involvement of medical physicists in the treatment planning process has been more variable and continues to evolve as clinical practices and professional expectations shift. Traditionally, the most common model of collaboration between dosimetrists and physicists involves physicists serving as secondary reviewers, ensuring quality and safety after the dosimetrist has completed the initial treatment plan. However, with the increasing complexity of modern radiotherapy techniques, which demand greater precision, personalization, and interdisciplinary coordination, many institutions face growing challenges in recruiting experienced treatment planners capable of handling complex cases. The need for extensive on-the-job training, often provided by senior dosimetrists and occasionally by physicists, places additional strain on departments already affected by workforce shortages. This situation raises an important question: should medical physicists assume a more formalized role as treatment planners? This debate examines the proposition that clinical medical physicists should participate routinely in the treatment planning process, not merely as reviewers or technical advisors, but as active contributors working alongside dosimetrists and radiation oncologists. The faculty physicist arguing for the proposition is Dr. Dongxu Wang from Memorial Sloan Kettering Cancer Center, while the faculty physicist arguing against the proposition is Dr. Douglas Prah from the Medical College of Wisconsin.&lt;/p&gt;&lt;p&gt;Dongxu Wang, PhD, MBA, received his PhD in Medical Physics from the University of Wisconsin-Madison in 2011. After graduate school, he joined the University of Iowa Hospitals and Clinics as a faculty physicist. While at the University of Iowa, he studied part-time and received his master's degree in business administration (MBA) in 2019. He is now an Associate Attending Physicist at Memorial Sloan Kettering Cancer Center. Dr. Wang's earlier expertise and focus were in proton therapy and proton imaging. Lately he is active in advancing medical physics leadership and professionalism education using the case study method.&lt;/p&gt;&lt;p&gt;Douglas Prah, PhD, DABR, is a board-certified medical physicist, Associate Professor of Radiation Oncology, and the Director of Advanced Care &amp; Technology at Froedtert &amp; the Medical College of Wisconsin. He earned his PhD in Biophysics from the Medical College of Wisconsin and specializes in radiation beam modeling, treatment planning, and integrating advanced technologies into clinical workflows. Dr. Prah chairs the Service and Technology Implementation and Review Committee and oversees medical dosimetry services across the enterprise. He is also an APEx Surveyor and","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 7","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70185","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144624324","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":"Univariate and multivariate analysis of the styrofoam fixation device on patient setup errors in radiotherapy","authors":"Jun Chen,&nbsp;Yi Guo,&nbsp;Changsheng Wang,&nbsp;Simin Lin,&nbsp;Linglong Shao,&nbsp;Linzhen Lan,&nbsp;Feibao Guo","doi":"10.1002/acm2.70181","DOIUrl":"https://doi.org/10.1002/acm2.70181","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Styrofoam is a patient-specific immobilization device in radiotherapy; most previous studies about the impact of styrofoam on setup errors have only analyzed a single tumor type, and have not considered the influence of patient's physical condition on the setup errors of styrofoam.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>This study aims to evaluate the impact of styrofoam device on setup errors in radiotherapy and explore which patient population is more suitable for styrofoam immobilization.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Univariate and multivariate analyses were conducted to compare the setup errors between the experimental group (styrofoam combined with thermoplastic mask) and the control group (thermoplastic mask alone). All cases were categorized based on tumor location into head and neck, thorax, abdomen, and limb cases, with age, gender, surgical history, educational level, and body mass index (BMI) serving as variables in the multivariate analysis. Intragroup analysis was also performed.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>For all included cases, the experimental group had median setup errors of 1.20 , 2.00 , and 1.30 mm in the vertical, longitudinal, and lateral directions, respectively. In contrast, the control group had median setup errors of 1.50 , 2.00 , and 1.85 mm in the same respective directions. Notably, the experimental group demonstrated statistically significant reductions in average setup errors in the longitudinal direction (2.00  vs. 2.87 mm, <i>p </i>&lt; 0.01) and lateral direction (1.90  vs. 2.24 mm, <i>p</i> &lt; 0.01) compared to the control group. The intragroup analysis results indicated that factors such as age, gender, surgical history, and educational level had no significant impact on the setup errors in the experimental group.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>The styrofoam fixation device for patient immobilization can effectively reduce setup errors in both the longitudinal and lateral directions, and the styrofoam fixation device is suitable for most people.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 7","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70181","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144624288","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":"Three discipline collaborative radiation therapy (3DCRT) special debate: AI structure segmentation is better than clinician contouring for both OARs and targets","authors":"Andrew Hope,&nbsp;Michelle Mundis,&nbsp;Jan-Jakob Sonke,&nbsp;John Kang,&nbsp;Stine Korreman,&nbsp;Brian Napolitano,&nbsp;Sharif Elguindi,&nbsp;Michael C. Joiner,&nbsp;Jay Burmeister,&nbsp;Michael M. Dominello","doi":"10.1002/acm2.70183","DOIUrl":"https://doi.org/10.1002/acm2.70183","url":null,"abstract":"&lt;p&gt;Radiation Oncology is a highly multidisciplinary medical specialty, drawing significantly from three scientific disciplines—medicine, physics, and biology. As a result, discussion of controversies or changes in practice within radiation oncology involves input from all three disciplines, and sometimes more! For this reason, significant effort has been expended recently to foster collaborative multidisciplinary research in radiation oncology, with substantial demonstrated benefit. In light of these results, we endeavor here to adopt this “team-science” approach to the traditional debates featured in this journal. This article is part of the series of special JACMP debates entitled “Three Discipline Collaborative Radiation Therapy (3DCRT)” in which each debate team typically includes a radiation oncologist, a medical physicist, and a radiobiologist. In this case, we have included a medical dosimetrist. We hope that this format will not only be engaging for the readership but will also foster further collaboration in the science and clinical practice of radiation oncology and developments thereof.&lt;/p&gt;&lt;p&gt;Artificial intelligence (AI) is ubiquitous. The applications are limitless and the effects are permeative. The use of AI for contouring of organs at risk (OARs) has been in the works now for many years, however as algorithms have improved and adaptive replanning is becoming increasingly prevalent in the clinic, physicians and radiation oncology teams are increasingly reliant on software for auto contouring, including in certain scenarios for contouring targets. In this debate, we consider the risks and benefits of this progression towards increased contouring by AI. At what point does the machine definitively outperform the clinician? Are we there yet? For this debate we will argue exactly this point through the proposition, “AI structure segmentation is &lt;i&gt;better&lt;/i&gt; than clinician contouring for both OARs and targets.” Arguing for the proposition will be John Kang, Stine Korreman, Brian Napolitano, and Sharif Elguindi. John Kang, MD, PhD, is an assistant professor in radiation oncology in the University of Washington Department of Radiation Oncology and the Fred Hutch Cancer Center. He is dual board certified in radiation oncology and clinical informatics and serves as clinical informatics lead. His clinical focus is on thoracic malignancies and his research focus is on natural language processing and informatics applications. Stine S Korreman, PhD, is Professor of Medical Physics at Aarhus University, Denmark. She leads a research group on AI for medical image analysis in radiotherapy with a focus on segmentation and dose prediction, and translation from research to clinical practice. She is chair of the ESTRO Focus Group AI in Radiotherapy and Director of the ESTRO course on AI in Radiotherapy. Brian Napolitano, MHL, CMD is Director of Medical Dosimetry at Massachusetts General Hospital in Boston, where he oversees treatment planning operation","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 7","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70183","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144624321","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":"Effects of various tilt angles on radiation dose and image quality in pediatric head computed tomography: A phantom study","authors":"Hongrong Xu,&nbsp;Jiawen Zhao,&nbsp;Zhen Xu,&nbsp;Bo Liu,&nbsp;Jinhua Cai","doi":"10.1002/acm2.70177","DOIUrl":"https://doi.org/10.1002/acm2.70177","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Various methods have been employed to reduce radiation dose and improve image quality in head computed tomography (CT); however, the impact of different head tilt angles on these factors remains underexplored.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Objective</h3>\u0000 \u0000 <p>To investigate the effects of different head tilt angles on radiation dose and image quality in head CT.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Materials and methods</h3>\u0000 \u0000 <p>A pediatric anthropomorphic head phantom was scanned using dual-source CT at 18 different tilt angles, repeated 10 times at each angle. Image quality was assessed using mean CT (CT_mean) attenuation values and image noise at six regions of interest (ROIs), while radiation dose was evaluated using volume CT dose index (CTDI_vol), size-specific dose estimate (SSDE), and dose-length product (DLP). The scan lengths of the eyes and head were also recorded.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>CTDI_vol and SSDE did not exhibit clear variation patterns with changes in head tilt angles, while DLP was in the lower region between −10° and 5°. Head scan lengths were relatively shorter between −10° and 5°, and eye scan lengths were relatively shorter between −10° and 0°. Except for the image noise of the right middle cranial fossa, no significant differences were found in CT_mean values and image noise for the other ROIs between −10° and 0°.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>The findings indicated that adjusting the head tilt angle within the range of −10° to 0° reduced both the head and eye scan lengths as well as the radiation dose, while preserving relatively stable image quality.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 7","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70177","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144624750","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":"CT scanning and questions about benefit versus risk","authors":"Cynthia H. McCollough,&nbsp;Rebecca Millman","doi":"10.1002/acm2.70179","DOIUrl":"https://doi.org/10.1002/acm2.70179","url":null,"abstract":"&lt;p&gt;Computed tomography (CT) was invented over 50 years ago and is considered one of the greatest medical advances of the 20th century.&lt;span&gt;&lt;sup&gt;1&lt;/sup&gt;&lt;/span&gt; Physicians depend on CT in myriad medical scenarios, from diagnosing and treating cancer patients to determining whether a surgery is necessary. CT increases diagnostic accuracy and decreases patient mortality.&lt;span&gt;&lt;sup&gt;2-8&lt;/sup&gt;&lt;/span&gt;&lt;/p&gt;&lt;p&gt;A recent publication&lt;span&gt;&lt;sup&gt;9&lt;/sup&gt;&lt;/span&gt; estimated that up to 5% of all future cancers in the U.S. may be caused by CT scans. The paper, and the ensuing media coverage, reinforced perceptions that CT scans are risky medical procedures that should be avoided. This perception is due in large part to similar papers by some of the same authors&lt;span&gt;&lt;sup&gt;10-12&lt;/sup&gt;&lt;/span&gt; and the alarmist reporting of these papers by large media outlets.&lt;/p&gt;&lt;p&gt;It is therefore essential that medical personnel, including medical physicists, be able to discuss this topic in a reassuring and well-informed manner when patients question the safety of a prescribed CT (or other exam or procedure involving ionizing radiation). Toward that end, the AAPM produced a communication guideline entitled &lt;i&gt;Radiation and Medical Imaging: Communicating Clear Answers to Top Questions&lt;/i&gt;.&lt;span&gt;&lt;sup&gt;13&lt;/sup&gt;&lt;/span&gt; The guide was written to help health professionals explain the benefits and risks of medical imaging to policy makers, care providers, patients, family members, and the public. In this editorial, we provide additional information for answering questions regarding cancer risk from CT.&lt;/p&gt;&lt;p&gt;First, it must be noted that the methods used by Smith-Bindman et al.&lt;span&gt;&lt;sup&gt;9&lt;/sup&gt;&lt;/span&gt; are fundamentally mathematical in nature; they assume a causal relationship between CT and cancer rather than prove it, and they provide no direct evidence of any single person getting cancer from a CT scan. They estimate 103 000 additional cancers might occur per 93 000 000 CT exams (0.1%) compared to what would otherwise be expected based on organ doses from modern CT exams, numbers of CT scans performed, and the BEIR VII&lt;span&gt;&lt;sup&gt;14&lt;/sup&gt;&lt;/span&gt; organ risk coefficients (scaled down from 100 mGy). Notably, the estimates are derived from risk coefficients published in BEIR VII—coefficients that were derived from very different populations, including populations with much higher doses than for CT.&lt;span&gt;&lt;sup&gt;14&lt;/sup&gt;&lt;/span&gt;&lt;/p&gt;&lt;p&gt;While BEIR VII is an important document, there are considerable limitations to the risk coefficients it provides. Data based on human exposures to radiation are extremely limited, making it necessary to form risk estimates from a combination of data from higher dose exposures (well above 100 mGy) and animal and cellular studies, most of which were performed with radiation exposures on the order of Gy rather than the 10s of mGy used in medical imaging exams. More recent risk estimates from medical exposures (specifically CT) suffer from multiple limiting or confounding fac","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 7","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70179","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144624883","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 multileaf collimator driving accuracy in helical rotational irradiation system: Quantitative analysis of leaf open time during treatment","authors":"Hirofumi Honda,&nbsp;Motoharu Sasaki,&nbsp;Masahide Tominaga,&nbsp;Kenji Omoto,&nbsp;Teruhito Kido","doi":"10.1002/acm2.70186","DOIUrl":"https://doi.org/10.1002/acm2.70186","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>The Radixact treatment system is equipped with a delivery analysis feature. This feature enables dose reconstruction using the patient's treatment-planning computed tomography scans and allows verification of the multileaf collimator (MLC) performance before and during treatment. In the Radixact system, the opening time of the MLC leaves is determined based on the treatment plan.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>This study aimed to evaluate MLC driving accuracy by assessing the MLC leaf open time (LOT) during treatment.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Using Delivery Analysis version 2.3, we compared the treatment plan LOT with the LOT measured during treatment to determine the average and one standard deviation (%) of the LOT attainment rate. The analysis included comparisons of treated sites across 39 cases: nine prostate, eight pelvic, seven head, six chest, five head and neck (H&amp;N), and four stereotactic body radiation therapy (SBRT) treatment plans.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The average and one standard deviation (%) of the LOT attainment rate for all patients on treatment was 94.56 ± 2.37. The values of each site were as follows: prostate, 95.93 ± 0.68; pelvis, 93.37 ± 2.16; head, 95.05 ± 1.99; chest, 97.61 ± 0.78; H&amp;N, 92.44 ± 1.32; and SBRT, 98.39 ± 0.57. The treatment plans with the lowest attainment rates for each site were as follows: prostate, 95.19 ± 0.39; pelvis, 90.59 ± 0.16; head, 92.20 ± 0.15; chest, 95.76 ± 0.04; H&amp;N, 90.55 ± 0.30; and SBRT, 97.32 ± 0.07. The plans with the largest one standard deviation (%) per site were as follows: prostate, ± 0.97; pelvis, ± 0.26; head, ± 0.57; chest, ± 0.23; H&amp;N, ± 0.30; and SBRT, ± 0.07.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>We proposed a simple method for quantitatively analyzing the LOT of an MLC. The average LOT attainment rate and its standard deviation varied by treatment site. Since the standard deviation differed by plan, the LOT attainment rate during treatment should be carefully monitored.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 7","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70186","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144624323","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":"Geometric characterization of an electromagnetic surface tracking system in a radiation therapy environment","authors":"Mumtaz Hussain Soomro,&nbsp;Junliang Xu,&nbsp;Jie Ding,&nbsp;Jochen Cammin,&nbsp;Narottam Lamichhane,&nbsp;Alex Van Slyke,&nbsp;Xiao Liang,&nbsp;Steve Roys,&nbsp;Jiachen Zhuo,&nbsp;Thomas Ernst,&nbsp;Rao P Gullapalli,&nbsp;Erez Nevo,&nbsp;Amit Sawant","doi":"10.1002/acm2.70187","DOIUrl":"https://doi.org/10.1002/acm2.70187","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Despite advances in image-guided radiation therapy (IGRT), real-time, soft-tissue-based, volumetric motion monitoring remains unsolved. Integrated MRI+Linac systems are a solution, but are costly and complex. X-ray and optical photogrammetry-based systems have their limitations. Surrogate-based motion models, which use external signals to estimate internal motion, offer an alternative. We explore the feasibility of an electromagnetic (EM) fiducial-based device integrated with a surrogate-based motion model for real-time in-room volumetric motion monitoring.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>To assess the feasibility of an EM-tracking system in the linac room, with an eventual goal of integrating it into an MRI-compatible system for real-time volumetric motion monitoring.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We empirically assessed the impact of gantry rotation and the radiation beam on EM-tracking accuracy using a sinusoidal motion trajectory (2 cm peak-to-peak, 5 s per cycle) programmed into a 2D motion platform. Four EM-tracking sensors were affixed to the platform, and their recorded trajectories were compared to the programmed motion under various conditions, including static and dynamic gantry positions, with and without radiation beams, and during CBCT acquisition.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The EM-tracking system faithfully reproduced the programmed sinusoidal motion during treatment beam (MV) and CBCT acquisition (kV + gantry rotation). With the beam off and static gantry and static motion platform at 0°, the average point-wise tracking difference was &lt; 0.5 mm compared to gantry angles of 90°, 180°, and 270°. Similarly, with a moving platform, the sensors achieved a &lt; 1 mm difference at the same angles. Additionally, the gantry's clockwise and anticlockwise rotations caused a &lt; 0.5 mm difference on average at all angles during beam-off.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>Preliminary results show the EM-tracking system operates with sub-millimeter accuracy in the linac room, with minimal effects from the radiation beam, gantry motion, or CBCT acquisition, supporting its feasibility for real-time volumetric motion monitoring during IGRT.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 7","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70187","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144624749","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":"Feasibility of segmental total body irradiation (SegTBI) using a 1.5T MR-linac","authors":"Matthew Manhin Cheung,&nbsp;Ashley Chi Kin Cheng,&nbsp;Louis Lee","doi":"10.1002/acm2.70192","DOIUrl":"https://doi.org/10.1002/acm2.70192","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Objective</h3>\u0000 \u0000 <p>To evaluate the technical feasibility of using the elekta unity magnetic resonance linac (MRL) as a backup for tomotherapy in total body irradiation (TBI) treatment.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>A single pediatric patient's TBI treatment with a prescription of 12 Gy in six fractions was retrospectively re-planned using a multiple-isocentre approach with dose feathering on the MRL system. An additional plan was created and delivered to an anthropomorphic phantom containing OSLDs. The study investigated the MRL system's limitations and capabilities.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The plan sum of the nine segments not only met the dosimetric criteria of planning targets but also demonstrated the MRL system's capabilities by keeping the mean lung dose below 8 Gy and the mean kidney dose below 10 Gy. The electron streaming effect was observed. Treatment plan verification using ArcCHECK measurements with a global 3%/2 mm gamma analysis had a pass rate greater than 95% for all segments. In 28 out of the 30 OSLDs in brain, bone, and soft tissues, the deviation of the measurement from the reported TPS dose is within ±5%. A much larger deviation was observed in the lung tissues. Segmental TBI using the MRL was a viable option for TBI treatment.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Significance</h3>\u0000 \u0000 <p>This study demonstrates the technical feasibility of MRL for TBI by offering dose modulation and imaging capabilities. The MRL can serve as a backup despite longer planning and treatment times. The potential for future workflow optimizations could enhance its practicality. This research improves flexibility in treatment planning and delivery for TBI patients.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 7","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70192","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144635374","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}