Journal of Applied Clinical Medical Physics最新文献

{"title":"Integrating medical physics into an EMR-based radiology feedback system for quality improvement","authors":"Megan K. Russ,&nbsp;Justin Solomon,&nbsp;Steve Bache,&nbsp;Nicole M. Lafata,&nbsp;Erin B. Macdonald,&nbsp;Ehsan Samei","doi":"10.1002/acm2.70227","DOIUrl":"10.1002/acm2.70227","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Introduction</h3>\u0000 \u0000 <p>Medical physicists play a critical role in ensuring image quality and patient safety, but their routine evaluations are limited in scope and frequency compared to the breadth of clinical imaging practices. An electronic radiologist feedback system can augment medical physics oversight for quality improvement. This work presents a novel quality feedback system integrated into the Epic electronic medical record (EMR) at a university hospital system, designed to facilitate feedback from radiologists to medical physicists and technologist leaders.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>The feedback system was designed to enable radiologists to report quality issues directly through a streamlined survey during report dictation. The feedback encompasses technical details including image noise, artifact, and contrast issues, as well as acquisition-related concerns such as positioning errors or protocol deviations. Submissions are routed to modality-specific teams consisting of technologist leaders and medical physicists, who investigate and address reported issues. The roles of medical physicists in this feedback system were evaluated over a 31-month period.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Physicists addressed 9.3% of 515 tickets that warranted follow-up, with greater involvement in resolving technical quality issues including artifacts and issues related to noise and image contrast. Examples of physicist-led interventions included correcting radiography image processing settings, optimizing computed tomography dose settings, and identifying trends in ultrasound quality issues that prompted protocol updates and staff training.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>This work demonstrates the value of radiology quality feedback systems and the opportunity to address issues not typically identified during routine medical physics quality assurance. By leveraging radiologist feedback, physicists can enhance clinical practice, promote continuous improvement, and ensure consistent, high-quality imaging and safety for patients.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 9","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://aapm.onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70227","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145021863","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 HyperSight CBCT for adaptive radiation therapy: A phantom benchmark study of dose calculation accuracy and delivery verification on the Halcyon","authors":"Nicholas Nelson,&nbsp;Courtney Oare,&nbsp;Geoff Nelson,&nbsp;Thomas Martin,&nbsp;Jessica Huang,&nbsp;Hui Zhao","doi":"10.1002/acm2.70245","DOIUrl":"10.1002/acm2.70245","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Purpose&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;The development of on-board cone-beam computed tomography (CBCT) has led to improved target localization and evaluation of patient anatomical change throughout the course of radiation therapy. HyperSight, a newly developed on-board CBCT platform by Varian, has been shown to improve image quality and HU fidelity relative to conventional CBCT. The purpose of this study is to benchmark the dose calculation accuracy of Varian's HyperSight cone-beam computed tomography (CBCT) on the Halcyon platform relative to fan-beam CT-based dose calculations and to perform end-to-end testing of HyperSight CBCT-only based treatment planning.&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 HU to mass density curve was measured for the HyperSight CBCT system and implemented into the Eclipse treatment planning system. Following this, computational dosimetric analysis was performed between dose distributions calculated on CT simulation (CT&lt;sub&gt;sim&lt;/sub&gt;) and HyperSight CBCT images on two anthropomorphic phantoms for pelvic and head and neck treatment sites. Additionally, an end-to-end test was carried out for a head and neck intensity modulated radiation therapy (IMRT) plan.&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 HU to mass density curves acquired on CT&lt;sub&gt;sim&lt;/sub&gt; and HyperSight CBCT were similar (&lt; 30 HU) for near-water equivalent materials, but deviated for high-density materials, with a maximum difference of 150 HU. For dose calculations, excellent agreement between dose calculations performed on CT&lt;sub&gt;sim&lt;/sub&gt; and HyperSight CBCT phantom images was observed, where three-dimensional gamma pass rates between the two dose distributions were observed to be &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 $&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;90% at 1%/1 mm (5% threshold). For the end-to-end test, absolute doses were verified to within 1% of ionization chamber measurements, while Delta4+ and portal dosimetry measurements yielded passing results (gamma pass rate &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mo&gt;≥&lt;/mo&gt;\u0000 &lt;annotation&gt;$ ge $&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; 90%) down to 2%/2 mm criterion.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Conclusion&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;In this study, the accuracy of dose calculations performed on HyperSight CBCT was found to be within 1% of CT&lt;sub&gt;sim&lt;/sub&gt; calculations for pelvic and head and neck treatment sites. End-to-end results ","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 9","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://aapm.onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70245","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145021934","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":"Verification of CT/MRI imaging protocol compliance for radiotherapy","authors":"Yunfei Hu,&nbsp;James D. Rijken,&nbsp;Marius Arnesen","doi":"10.1002/acm2.70246","DOIUrl":"10.1002/acm2.70246","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Introduction</h3>\u0000 \u0000 <p>The role of imaging in radiotherapy is becoming increasingly important. Verification of imaging parameters prior to treatment planning is essential for safe and effective clinical practice.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>This study described the development and clinical implementation of ImageCompliance, an automated, GUI-based script designed to verify and enforce correct CT and MRI parameters during radiotherapy planning.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Since its deployment, ImageCompliance has processed more than 48,000 CT and MRI studies. The integration of the centralized database eliminated the need for manual uploads, reducing workflow inefficiencies. The multi-tier warning system facilitated timely identification of deviations from protocol, thereby supporting clinical decision-making and ensuring protocol adherence.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>The clinical implementation of ImageCompliance safeguards geometric and dosimetric accuracy, informs margin selection, and enhances governance over imaging protocols. It represents an effective strategy for the verification of CT/MRI imaging protocol compliance for radiotherapy.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 9","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://aapm.onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70246","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145021897","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":"Clinical comparison of four commercial MRI phantoms on a 0.35T MR-linac using a standard clinical TRUFI sequence at a single institution","authors":"Mateb Al Khalifa,&nbsp;Tianjun Ma,&nbsp;Haya Aljuaid,&nbsp;Siyong Kim,&nbsp;William Y. Song","doi":"10.1002/acm2.70247","DOIUrl":"10.1002/acm2.70247","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>Real‑time magnetic resonance–guided radiation therapy (MRgRT) integrates MRI with a linear accelerator (Linac) for gating and adaptive radiotherapy, which requires robust image‑quality assurance over a large field of view (FOV). Specialized phantoms capable of accommodating this extensive FOV are therefore essential. This study compares the performance of four commercial MRI phantoms on a 0.35 T MR‑Linac.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Four phantoms: the IBA QUASAR Insight Phantom, the IBA QUASAR MRID^3D Geometric Distortion Phantom, the MagPhan Phantom, and the Sun Nuclear Large Field MRI Distortion Phantom, were evaluated on a 0.35 T MR-Linac using the TRUFI clinical sequence. Mean distortions were measured at gantry angles from 0° to 360° in 30° increments. Clinical imaging parameters (signal-to-noise ratio, uniformity, resolution via modulation transfer function, laser alignment, and twist) were also assessed where applicable.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The QUASAR MRID^3D Phantom enabled separate quantification of B₀ and gradient-induced distortions but showed a notable vertical offset, which did not affect comparisons with other phantoms. Both the MagPhan and QUASAR Insight phantoms provided mean distortion measurements as well as additional imaging parameters (e.g., signal-to-noise ratio, uniformity, resolution). The Sun Nuclear Phantom exhibited higher overall distortion values.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>All four phantoms successfully measured distortion at multiple gantry angles on a 0.35 T MR-Linac. The QUASAR MRID^3D Phantom uniquely differentiated B₀ from gradient distortions but required an offset adjustment. The MagPhan and QUASAR Insight phantoms offered comprehensive imaging metrics, while the Sun Nuclear Phantom exhibited relatively higher distortions.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 9","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://aapm.onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70247","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145021935","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":"Enhancing patient-specific quality assurance for VMAT for breast cancer treatment: A machine learning approach for gamma passing rate (GPR) prediction","authors":"Francis C. Djoumessi Zamo,&nbsp;Anthony Colliaux,&nbsp;Valérie Blot-Lafond,&nbsp;Ndontchueng Moyo,&nbsp;Christopher F Njeh","doi":"10.1002/acm2.70251","DOIUrl":"10.1002/acm2.70251","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Modern radiation therapy for breast cancer has significantly advanced with the adoption of volumetric modulated arc therapy (VMAT), offering enhanced precision and improved treatment efficiency.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>To ensure the accuracy and precision of such complex treatments, a robust patient-specific quality assurance (PSQA) protocol is essential. This study investigates the potential of machine learning (ML) models to predict gamma passing rates (GPR), a key metric in PSQA.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>A dataset comprising 863 VMAT plans was used to develop and compare seven ML models: Histogram-based gradient boosting regressor, random forest regressor, extra trees regressor, gradient boosting regressor, linear regression, AdaBoost regressor, and Multi-layer perceptron regressor. These models incorporated anatomical, dosimetric, and plan complexity features.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Among the evaluated models, the extra trees regressor (ETR), random forest regressor (RFR), and gradient boosting regressor (GBR) demonstrated the best performance, achieving mean absolute errors (MAEs) of 0.51%, 0.52%, and 0.51%, and mean squared errors (MSEs) of 0.0051%, 0.0051%, and 0.0052%, respectively, on the validation dataset.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>This study highlights the promise of ML-based approaches in streamlining PSQA processes, thereby supporting the quality assurance of breast cancer treatments using VMAT.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 9","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://aapm.onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70251","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145012391","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":"Dosimetric accuracy of low dose rate volumetric modulated arc therapy delivery in an Elekta Versa HD linear accelerator for pulsed low dose rate treatment of recurrent high-grade glioma using Monaco planning system","authors":"Surendran Jagadeesan,&nbsp;S. P. Vijaya Chamundeeswari","doi":"10.1002/acm2.70253","DOIUrl":"10.1002/acm2.70253","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background and purpose</h3>\u0000 \u0000 <p>Reducing the dose rate enhances efficacy in radiation therapy by allowing increased repair of sub-lethal damage. Pulsed low-dose radiation therapy (PLDR) is an innovative approach that is safe and effective for the reirradiation of recurrent gliomas and radioresistant tumors. In this study, the accuracy of the low dose rate volumetric modulated arc therapy (VMAT) delivery is tested in an Elekta Versa HD linear accelerator (linac) for delivering PLDR.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Material and methods</h3>\u0000 \u0000 <p>A retrospective study was conducted on ten patients previously treated for high-grade glioma. The Monaco planning system was used to create two or three arc VMAT plans with a minimum monitor unit (MU) exceeding 570. The Mosaiq record and verification system (R&amp;V) was used to select dose rates between 20 and 25 MU/min for delivering VMAT beams, achieving a beam-on time of 30 min and an effective dose rate of 6.7 cGy/min. Measurements from IBA MatriXX resolution were used for gamma analysis. Beam characteristics at low dose rates for 8 gantry angles were investigated using the measurements from the dolphin detector.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>All the deviations of flatness and symmetry were within 1.0% in all gantry angles. MU linearity was within 1% for the lowest dose rate of 20 MU/min. The output deviations were within 1% for all dose rates. The average dose rate achieved was 6.7 ± 0.1 cGy/min. The maximum dose rate achieved in the planning target volume (PTV) was 7.28 (6.86 to 7.28) cGy/min. The gamma pass rate was above 97%, with the analysis criterion 3%3 mm, 2%2 mm, and 2%1 mm for VMAT delivered at a low dose rate.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>Low-dose rate VMAT delivery is feasible with higher accuracy in the delivered dose on the Elekta Versa HD linac. PLDR can be implemented successfully on Elekta linacs using the Monaco planning system.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 9","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://aapm.onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70253","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144934946","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":"Radiation dose and shielding considerations for digital dynamic radiography (DDR) compared to mobile C-arms","authors":"Azmul Siddique,&nbsp;Gary Ge,&nbsp;Jie Zhang","doi":"10.1002/acm2.70256","DOIUrl":"10.1002/acm2.70256","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;Digital dynamic radiography (DDR), integrated into Konica Minolta's portable mKDR system, provides dynamic imaging for pulmonary, orthopedic, and interventional applications. While DDR is not classified as fluoroscopy, its use of pulsed x-rays for cine-like image sequences raises concerns about radiation exposure and shielding, particularly given the absence of a primary beam stop, high output capabilities, and increasing clinical adoption.&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 characterize the primary and scatter radiation output of a DDR system and compare it against commonly used mobile C-arm fluoroscopy units, and to evaluate shielding requirements and potential occupational exposure risks associated with DDR use.&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;Radiation dose output and scatter were assessed for a Konica Minolta mKDR system and three mobile C-arms: GE OEC Elite, Siemens Cios Spin, and Ziehm Vision RFD 3D. Unshielded primary air kerma was measured at 100 cm SID using matched dose settings (low, medium, high). Scatter fraction and normalized scatter were measured at eight angles and three distances using a 20 cm PMMA phantom and an ion chamber. Additional direct comparisons of angular scatter doses between DDR and a GE C-arm were made during 20-s acquisitions at varying distances. The Klein–Nishina differential cross section was also calculated for photon energies representative of clinical settings. Leakage radiation and image receptor attenuation were quantified. Shielding requirements were estimated using NCRP 147 methodology under varying workload and occupancy conditions.&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;DDR exhibited dose rates two to three times higher than C-arms at medium and high dose settings, with longer pulse widths (16 ms) producing greater exposure than shorter ones (5 ms). Scatter fraction peaked at 165° and increased with lower beam energy due to energy-dependent Compton interactions and reduced filtration. Compared to the GE C-arm, DDR produced consistently higher scatter values at all angular positions. Measured scatter doses at 0.3 m and 1.0 m from the phantom exceeded those from the C-arm, especially in the forward direction (0°). Image receptor attenuation measurements showed 98% beam reduction when the receptor was properly aligned. Leakage was minimal and well below FDA limits. Shielding assessments indicated that concrete thickness requirements for DDR could reach 145 mm under worst-case conditions, driven primarily by the high primary beam out","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 9","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://aapm.onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70256","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144934948","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":"Efficient MLC quality assurance using a virtual picket fence test in an MR-Linac","authors":"Kai Yuan,&nbsp;Matthew Manhin Cheung,&nbsp;Louis Lee","doi":"10.1002/acm2.70232","DOIUrl":"10.1002/acm2.70232","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>The Elekta Unity MR-Linac system integrates magnetic resonance imaging (MRI) with a linear accelerator (Linac) for adaptive radiation therapy. Traditional quality assurance (QA) methods for multi-leaf collimators (MLCs) face challenges in this system due to the magnetic field and limited field size of electronic portal imaging devices (EPID).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>This study aims to develop a ‘virtual picket fence’ test using machine log files to evaluate MLC performance in the Elekta Unity MR-Linac system, providing a more efficient and comprehensive QA method that overcomes the limitations of traditional approaches.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>A picket fence test plan with 11 segments was delivered on the Elekta Unity system. Maximum absolute error and root mean square (RMS) error for each leaf were calculated by comparing log file data with nominal values. A deliberate 1 mm error was introduced in selected MLCs to test the sensitivity of the virtual test. The results from the log file were further compared with measurements from radiochromic films.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The maximum deviation between log file data and nominal values was within 1 mm for all leaves. The virtual picket fence test successfully identified MLCs with deviations beyond the 0.5 mm warning threshold in the error-introduced test. Comparisons with film-based measurements showed good agreement, with deviations between film and log file data also within 1 mm.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The virtual picket fence test provides an efficient and comprehensive method for MLC QA in the Elekta Unity MR-Linac system. This method can be integrated into weekly QA workflows alongside traditional film-based methods for thorough quality control.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 9","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://aapm.onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70232","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144934945","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":"Enhancing patient-specific quality assurance in MR-guided radiation therapy: A fluence-based method using log files","authors":"Kai Yuan,&nbsp;Matthew Man-hin Cheung,&nbsp;Louis Lee","doi":"10.1002/acm2.70238","DOIUrl":"10.1002/acm2.70238","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Patient-specific quality assurance (PSQA) is crucial in radiation therapy to ensure accurate and safe dose delivery. The Elekta Unity MR-Linac system, which combines MRI with a linear accelerator, presents unique challenges for conventional PSQA methods due to its adaptive capabilities and the presence of a magnetic field.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>This study introduced a novel PSQA method for the Elekta Unity MR-Linac system, utilizing treatment log files and fluence map verification to provide a more efficient alternative to traditional measurement-based techniques.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>The proposed method analyzed log file data, including monitor units (MU), multi-leaf collimator (MLC) positions, and jaw positions, comparing them with treatment planning system (TPS) values. Fluence maps were generated for each gantry angle and evaluated using gamma analysis. A user-friendly interface was developed to streamline the process.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The method was tested on nine stereotactic body radiation therapy (SBRT) cases, showing strong concordance between planned and delivered parameters. MU deviations were within 0.5 MU, X-jaw and MLC leaf position deviations were under 1 mm, and gamma analysis of fluence maps achieved passing rates above 98% for all gantry angles.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>This log file-based PSQA method offered distinct advantages over traditional measurement-based approaches, including reduced QA time, direct assessment of the delivered plan, and comprehensive evaluation of treatment parameters. This method provided an efficient and accurate alternative PSQA solution for MR-guided adaptive radiotherapy.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 9","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://aapm.onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70238","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144934947","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":"Why diagnostic and nuclear medical physicists matter in academic medical centers: A perspective from a radiology department chair and a medical physicist","authors":"Jie Zhang,&nbsp;M. Elizabeth Oates","doi":"10.1002/acm2.70255","DOIUrl":"10.1002/acm2.70255","url":null,"abstract":"&lt;p&gt;Diagnostic and nuclear medical physicists are central to quality, safety, and innovation in radiology, yet their contributions are often underrecognized. Since 2011, our department has developed a Division of Diagnostic &amp; Nuclear Medical Physics from the ground up. The team now includes three ABR‑certified PhD diagnostic physicists, a MS health physicist, a part‑time PhD MRI scientist, a physicist assistant, and two residents. From time to time, we are asked who physicists are, what they do, and why radiology needs an integrated physics division. As a department chair (MEO) and a physicist (JZ), we offer a joint perspective on why physicists are essential and how departments can better leverage and empower them as faculty, leaders, and innovators.&lt;/p&gt;&lt;p&gt;The American Association of Physicists in Medicine (AAPM) defines medical physics as a branch of applied physics concerned with the application of the concepts and methods of physics to the diagnosis and treatment of human disease. Clinical medical physicists specialize in diagnostic imaging, nuclear medicine, or therapy. Their shared responsibility is to ensure that radiation is used safely and effectively to achieve clinical goals. In theory, medical physicists, regardless of specialty, play an equally complementary role to other medical professionals. However, in reality, diagnostic and nuclear physicists often must justify their roles, while therapeutic physicists are widely accepted because their work is visibly tied to treatment planning, delivery, documentation, and reimbursement. Two factors drive the disparity for diagnostic and nuclear physics: the lack of reimbursement mechanisms and inconsistent perceptions of physicist roles in imaging. Although the AAPM, the American College of Radiology (ACR), and the literature outline these responsibilities, many radiology teams still consider diagnostic physicists as optional.&lt;span&gt;&lt;sup&gt;1-4&lt;/sup&gt;&lt;/span&gt; Samei and Seibert observed that even substantial academic centers undervalue this potential, with groups either nonexistent or understaffed and poorly integrated into patient care&lt;span&gt;&lt;sup&gt;5&lt;/sup&gt;&lt;/span&gt;. Since the time of Roentgen, medical physicists have bridged the gap between physics and medicine and catalyzed translational advances to improve patient care. Today, as imaging grows more complex, data-intensive, and technology-driven, physicists are indispensable in ensuring quality, safety, and clinical excellence.&lt;/p&gt;&lt;p&gt;Physicists add clinical value to radiology practice across imaging modalities. At our institution, physicists are embedded in daily operations, overseeing more than 200 imaging systems at 11 locations. They lead acceptance testing and calibration, integrate new technologies, and monitor performance. They optimize radiation dose by reviewing protocols and monitoring exposure to balance image quality and safety. Their work supports state and federal requirements, the Joint Commission, and ACR accreditation, including our ","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 9","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://aapm.onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70255","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144927276","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}