Journal of Applied Clinical Medical Physics最新文献

{"title":"Automatic skin flash optimization in breast and chestwall VMAT with static angle modulated ports: Effect of HU and flash margin size on plan quality and robustness","authors":"Emily Hubley,&nbsp;Brandon Koger,&nbsp;Taoran Li,&nbsp;Michael Salerno,&nbsp;Ryan M. Scheuermann,&nbsp;Lei Dong,&nbsp;Boon-Keng Kevin Teo","doi":"10.1002/acm2.70036","DOIUrl":"10.1002/acm2.70036","url":null,"abstract":"<p>Skin flash is typically added to breast and chestwall plans to ensure robust target coverage in the presence of respiratory motion, anatomic changes, and small setup uncertainties. Adding skin flash in volumetric modulated arc therapy (VMAT) plans is an iterative and manual process. RapidArc dynamic (RAD) is a new solution that integrates a dynamic collimator and static-gantry angle modulated ports directly into arc delivery. The automatic skin flash tool (ASF) allows users to automatically add skin flash directly within the optimizer. The user must select the thickness and Hounsfield Units (HUs) of the flash region, but the optimal values are not currently known. For 13 left- and right-sided breast and chestwall patients, RAD plans were created with no skin flash and with ASF with thickness of 5 to 20 mm and HU of −500 to 0 HU. To assess plan quality, DVH metrics for planning target volume (PTV), heart, ipsilateral lung, contralateral lung, and contralateral breast were recorded. To assess plan robustness, the isocenter was shifted 5 mm, moving the target 5 mm anteriorly into the flash region. The changes in clinical target volume (CTV) D95% and D99% were recorded. A paired <i>t</i>-test was used to determine if changes in plan quality or robustness were statistically significant (<i>p</i> ≤ 0.05). The addition of ≥ 7 mm of skin flash resulted in robust plans. Varying the HU did not affect robustness. Increasing the skin flash beyond 10 mm increased PTV V105%. This increase was much larger in the 0 HU plans than in the −350 HU plans. We therefore recommend using −350 HU and 7–10 mm of skin flash for anticipated inter- and intra-fraction motion of 5 mm.</p>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 5","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70036","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143476611","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":"T2-weighted imaging of rectal cancer using a 3D fast spin echo sequence with and without deep learning reconstruction: A reader study","authors":"Dan Nguyen,&nbsp;Sarah Palmquist,&nbsp;Ken-Pin Hwang,&nbsp;Jingfei Ma,&nbsp;Usama Salem,&nbsp;Jia Sun,&nbsp;Xinzeng Wang,&nbsp;Jong Bum Son,&nbsp;Randy Ernst,&nbsp;Peng Wei,&nbsp;Harmeet Kaur,&nbsp;Nir Stanietzky","doi":"10.1002/acm2.70031","DOIUrl":"10.1002/acm2.70031","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>To compare image quality and clinical utility of a T2-weighted (T2W) 3-dimensional (3D) fast spin echo (FSE) sequence using deep learning reconstruction (DLR) versus conventional reconstruction for rectal magnetic resonance imaging (MRI).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>The study included 50 patients with rectal cancer who underwent rectal MRI consecutively between July 7, 2020 and January 20, 2021 using a T2W 3D FSE sequence with DLR and conventional reconstruction. Three radiologists reviewed the two sets of images, scoring overall SNR, motion artifacts, and overall image quality on a 3-point scale and indicating clinical preference for DLR or conventional reconstruction based on those three criteria as well as image characterization of bowel wall layer definition, tumor invasion of muscularis propria, residual disease, fibrosis, nodal margin, and extramural venous invasion.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Image quality was rated as moderate or good for both DLR and conventional reconstruction for most cases. DLR was preferred over conventional reconstruction in all of the categories except for bowel wall layer definition.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>Both conventional reconstruction and DLR provide acceptable image quality for T2W 3D FSE imaging of rectal cancer. DLR was clinically preferred over conventional reconstruction in almost all categories.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 5","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70031","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143458003","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":"Assessing the rigidity of thermoplastic masks for head immobilization effectiveness in stereotactic radiosurgery","authors":"Iris Pasion Apale,&nbsp;Adam Agnew,&nbsp;Daniel Foley","doi":"10.1002/acm2.70058","DOIUrl":"10.1002/acm2.70058","url":null,"abstract":"<p>This study compared three Brainlab thermoplastic masks—Cranial 4pi basic, stereotactic (Close Mask V2), and open-face—to see how well they limited head movement during Stereotactic Radiosurgery (SRS). Using a head phantom, we tested rotational movements (pitch, yaw, and roll) and measured displacements with the ExacTrac system. The open-face mask had the smallest mean displacements (pitch: 0.14 ± 0.03°, yaw: 0.11 ± 0.02°, roll: 0.16 ± 0.03°) and performed slightly better than the stereotactic mask in pitch (0.20 ± 0.04°, <i>p</i> = 0.0173). The stereotactic mask performed similarly in yaw (0.09 ± 0.02°) and roll (0.16 ± 0.04°). The basic mask showed much more movement (pitch: 0.44 ± 0.13°, yaw: 0.28 ± 0.07°, roll: 0.26 ± 0.07°), making it less suitable for SRS. These results apply to the solid two-piece masks tested here and show that both the open-face and stereotactic masks provide reliable immobilization for accurate SRS treatments.</p>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 5","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70058","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143468248","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":"A comparative analysis of deep learning architectures with data augmentation and multichannel input for locoregional breast cancer radiotherapy.","authors":"Rosalie Klarenberg, Nienke L M Bakx, Coen W Hurkmans","doi":"10.1002/acm2.70047","DOIUrl":"https://doi.org/10.1002/acm2.70047","url":null,"abstract":"<p><strong>Purpose: </strong>Studies on deep learning dose prediction increasingly focus on 3D models with multiple input channels and data augmentation, which increases the training time and thus also the environmental burden and hampers the ease of re-training. Here we compare 2D and 3D U-Net models with clinical accepted plans to evaluate the appropriateness of using less computationally heavy models.</p><p><strong>Methods: </strong>A 2D Attention U-Net, a 2D HD U-Net, and a 3D U-Net were trained using 1 or 5 input channels with or without data augmentation and data from 89 locoregional breast cancer patients. Results were compared to clinically accepted plans. The significance of inclusion of more channels or data augmentation was compared to the base models and the HD U-Net and Attention U-Net were compared to their respective identically trained counterparts.</p><p><strong>Results: </strong>The Attention U-Net reached fewest PTV clinical goals (28%, mostly due to a too high average breast PTV dose) and improved using significantly using five channels and augmentation (49%). The HD U-Net already fulfilled 70% of the PTV goals, which did not improve much by adding more channels or augmentation. The 3D U-Net with five channels and augmentation reached 76%, compared to 81% in the clinically accepted plans. The lower rates for the HD U-Net compared to the 3D U-Net and clinical plans were mainly caused by a lower PTVn1n2 D98%, which was still on average 93%. Organ-at-risk goals were met in most cases for all models. Training time was approximately 8 fold for the 3D model.</p><p><strong>Conclusions: </strong>Comparable results to a 3D U-Net and clinical plans can be reached with a 2D HD U-net for a dataset size commonly seen in clinical practice. The Attention U-Net did profit from adding extra channels and data augmentation but did not reach the same level of accuracy as the other models.</p>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":" ","pages":"e70047"},"PeriodicalIF":2.0,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143468244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of acceleration treatment on treatment plan and delivery qualities in tomotherapy for lung cancer","authors":"Ryosuke Shirata,&nbsp;Tatsuya Inoue,&nbsp;Yugo Ebinuma,&nbsp;Akihiro Yamano,&nbsp;Takayuki Yagihashi,&nbsp;Hironori Nagata,&nbsp;Yumiko Minagawa,&nbsp;Yuki Mukai,&nbsp;Akiko Sato,&nbsp;Motoko Omura","doi":"10.1002/acm2.70049","DOIUrl":"10.1002/acm2.70049","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Acceleration treatment (AT) is a novel treatment planning parameter introduced in the tomotherapy-dedicated treatment planning system, Precision. This study explores the effects of AT on tomotherapy plans using helical (TomoHelical) and direct (TomoDirect) irradiation techniques.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>This study enrolled 20 patients with lung cancer. Initially, 10 TomoHelical and 10 TomoDirect treatment plans were created for each patient, utilizing patient-specific field width and pitch with an AT setting of 0. These original plans were subsequently reoptimized by changing only the AT values to 1, 4, 7, and 10 without changing other calculation parameters to assess the impact of AT on dosimetric and delivery parameters. Additionally, the deliverability of all plans was evaluated through patient-specific quality assurance using gamma analysis.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Increasing the AT from 0 to 10 led to a slight increase in maximum doses and a decrease in minimum doses within the target volume, thereby impairing dose homogeneity. Dose conformity to the target also deteriorated. Conversely, target coverage and delivery time improved considerably with higher AT values. Moreover, doses to organs at risk, including the lung, spinal cord, heart, and esophagus, remained clinically acceptable across all plans. Changes in these doses and the gamma pass rate in patient-specific quality assurance were negligible with variations in AT. This trend was consistent across both delivery techniques.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>AT is a crucial parameter in tomotherapy planning for modulating plan and delivery qualities. Higher AT values can enhance target coverage and delivery time efficiency.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 5","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70049","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143457998","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":"Determination of appropriate energy threshold range for accurate estimation of effective atomic number considering statistical uncertainty in photon-counting techniques","authors":"Tomonobu Haba,&nbsp;Hiroaki Hayashi,&nbsp;Tsukasa Takahashi,&nbsp;Shota Naito,&nbsp;Yuichi Furukawa,&nbsp;Shuichiro Yamamoto,&nbsp;Natsumi Kimoto,&nbsp;Shigeki Kobayashi","doi":"10.1002/acm2.70007","DOIUrl":"10.1002/acm2.70007","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>The energy threshold is an important parameter for precise material identification employing photon-counting techniques. However, in such applications, the appropriate energy threshold has not been clarified. Therefore, we aimed to determine the appropriate energy threshold range for precise material identification, focusing on effective atomic number (<i>Z</i>) values as an index.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>The atomic number was estimated using a previously proposed algorithm and Monte Carlo simulations. This algorithm included three steps: calculating the attenuation factor from the incident photon counts on a photon-counting detector, correcting the beam-hardening effects, and estimating the atomic number from the attenuation factor index using the calibration curve. Monte Carlo simulations were performed to add Poisson noise to an ideal x-ray spectrum. The total number of incident x-rays was set in the range of 10³–10⁶. The x-ray spectra were generated at tube voltages of 50–120 kV. Polymethyl methacrylate (<i>Z</i> = 6.5) and aluminum (<i>Z</i> = 13) were used for the analysis. The energy threshold was varied at intervals of 1 keV to estimate the atomic number. We evaluated the appropriate energy threshold range for accurately estimating the atomic number using the obtained atomic number data and statistical uncertainty under various conditions.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The appropriate energy threshold range was found to be 31–38 keV for a tube voltage range of 50–120 kV. At this energy threshold, the atomic number can be estimated within an accuracy of ± 0.7 at 10⁵ counts for the atomic number range of 6.5 (PMMA) to 13 (Al).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>We found the appropriate energy threshold range. The findings of this study are expected to be useful for appropriately setting the energy threshold during precise material identification using photon-counting detectors for clinical applications.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 4","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143468172","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":"Dose rate correction of a diode array for universal wedge field dosimetric verification.","authors":"Linyi Shen, Mengyang Li, Guiyuan Li, Xinyuan Chen, Shouping Xu, Jianrong Dai, Yuan Tian","doi":"10.1002/acm2.70050","DOIUrl":"https://doi.org/10.1002/acm2.70050","url":null,"abstract":"<p><strong>Purpose: </strong>To study the performance of MapCHECK 3 (MC3) in measuring universal wedge fields and propose a dose rate correction strategy to improve MC3 measurement accuracy.</p><p><strong>Materials and methods: </strong>Universal wedge fields with different wedge angles and field sizes were measured at different depths using MC3. Considering the more prominent dose rate dependence of type 4 diodes equipped by MC3, a program was developed to automatically correct the measurements based on the instantaneous dose rate (IDR) correction curve. Central axis (CAX) doses and off-axis doses along the wedge direction, with and without the correction, were compared with those measured by an ion chamber under the same condition. Measurements using MC3 with and without correction were also compared with the planned doses calculated by the treatment planning system (TPS).</p><p><strong>Results: </strong>If MC3 was used for universal wedge field measurement with the dose calibration factor (DCF) derived from a reference open field, an error of up to -2.4% would be introduced into the CAX dose. Other factors (field size and measurement depth) would also affect the accuracy of measurement when they differed from the absolute dose calibration and the maximum error was up to -2.9%. While greater errors were observed in the off-axis doses at the heel side of the wedge compared to the toe side due to the greater effective thickness of the wedge inserted into the beam. After dose rate correction, the deviations in the CAX dose were reduced to within ± 1.5%. The average gamma pass rate was also improved to over 99.5%.</p><p><strong>Conclusion: </strong>Because of the more prominent dose rate dependence of type 4 diodes, MC3 is not suitable for universal wedge field measurement using the methodology for open field measurement. The correction strategy proposed in this study is convenient and can improve the accuracy of universal wedge field measurement using MC3.</p>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":" ","pages":"e70050"},"PeriodicalIF":2.0,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143447635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Does dose calculation algorithm affect the dosimetric accuracy of synthetic CT for MR-only radiotherapy planning in brain tumors?","authors":"Jeffrey C. F. Lui,&nbsp;Francis K. H. Lee,&nbsp;C. C. Law,&nbsp;James C. H. Chow","doi":"10.1002/acm2.70030","DOIUrl":"10.1002/acm2.70030","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>This study compares the dosimetric accuracy of deep-learning-based MR synthetic CT (sCT) in brain radiotherapy between the Analytical Anisotropic Algorithm (AAA) and AcurosXB (AXB). Additionally, it proposes a novel metric to predict the dosimetric accuracy of sCT for individual post-surgical brain cases.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Materials and Methods</h3>\u0000 \u0000 <p>A retrospective analysis was conducted on 20 post-surgical brain tumor patients treated with Volumetric Modulated Arc Therapy (VMAT). sCT and planning CT images were obtained for each patient. Treatment plans were optimized on sCT and recalculated on planning CT using both AAA and AXB. Dosimetric parameters and 3D global gamma analysis between sCT and planning CT were recorded. The bone volume ratio, a novel metric, was calculated for each patient and tested its correlation with gamma passing rates.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>For AAA, the mean differences in D_mean and D_max of PTV between sCT and planning CT were 0.2% and −0.2%, respectively, with no significant difference in PTV (<i>p</i> &gt; 0.05). For AXB, mean differences in D_mean and D_max of PTV were 0.3% and 0.2%, respectively, with significant differences in D_mean (<i>p</i> = 0.016). Mean gamma passing rates for AXB were generally lower than AAA, with the most significant drop being 9.3% using 1%/1 mm analyzed in PTV. The bone volume ratio showed significant correlation with gamma passing rates.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Compared to AAA, AXB reveals larger dosimetric differences between sCT and planning CT in brain photon radiotherapy. For future dosimetric evaluation of sCT, it is recommended to employ AXB or Monte Carlo algorithms to achieve a more accurate assessment of sCT performance. The bone volume ratio can be used as an indicator to predict the suitability of sCT on a case-by-case basis.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 5","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70030","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143449287","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":"Evaluating the use of diagnostic CT with flattening filter free beams for palliative radiotherapy: Dosimetric impact of scanner calibration variability.","authors":"Madeleine L Van de Kleut, Lesley A Buckley, Elsayed S M Ali","doi":"10.1002/acm2.70040","DOIUrl":"https://doi.org/10.1002/acm2.70040","url":null,"abstract":"<p><strong>Purpose: </strong>Palliative radiotherapy comprises a significant portion of the radiation treatment workload. Volumetric-modulated arc therapy (VMAT) improves dose conformity and, in conjunction with flattening filter free (FFF) delivery, can decrease treatment times, both of which are desirable in a population with a high probability of retreatment with large palliative doses per fraction. Combining FFF and VMAT delivery with planning based on previously acquired diagnostic computed tomography (CT) scans has the potential to further expedite palliative treatment. This study evaluated the dosimetric uncertainty of using FFF beams with VMAT delivery on CT images acquired from different diagnostic vendors, and between different x-ray tube energies, in the palliative setting.</p><p><strong>Methods: </strong>CT-relative electron density (CT-RED) curves were acquired for the local CT simulator at 100, 120, and 140 kVp, and for two diagnostic CT scanners at 120 kVp. Thirty palliative VMAT plans were recalculated for each CT-RED curve, with 6 MV flat, 6 FFF, and 10 FFF beams. The doses to 95% and 2% of the PTV, the maximum point dose to the spinal canal and esophagus, and the mean dose to the kidneys were compared between recalculated plans.</p><p><strong>Results: </strong>Comparing the dose clouds for a given fluence map calculated with CT-RED curves from different CT scanners at 120 kVp, the mean dose difference was at most 0.3% for each DVH metric. Similar results were reported when comparing dose clouds calculated with CT-RED curves for 100, 120, and 140 kVp on the CT simulator.</p><p><strong>Conclusion: </strong>The results of this study confirm that diagnostic scans acquired on machines different from the CT simulator associated with the TPS, are appropriate for VMAT treatment planning in the palliative setting with FFF photon beams.</p>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":" ","pages":"e70040"},"PeriodicalIF":2.0,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143448195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"From 2D to 3D gamma passing rate tolerance and action limits for patient-specific quality assurance in volumetric-modulated arc therapy.","authors":"Christos Zarros, George Patatoukas, Nikos Kollaros, Marina Chalkia, Andromachi Kougioumtzopoulou, Vasilios Kouloulias, Kalliopi Platoni","doi":"10.1002/acm2.70025","DOIUrl":"https://doi.org/10.1002/acm2.70025","url":null,"abstract":"<p><strong>Background: </strong>Volumetric modulated arc therapy (VMAT) requires an accurate patient-specific quality assurance (PSQA) program. In clinical practice, this is usually performed using the γ-index and the two-dimensional gamma passing rate (2D %GP). A three-dimensional (3D) index incorporating the patient anatomy could be more useful for the 3D dose distribution verification.</p><p><strong>Purpose: </strong>The current study demonstrates a thorough investigation of VMAT PSQA treatment plans by examining the correlation between 3D Gamma passing rate (%GP) and 2D %GP. The aim was to establish the tolerance limits (TL) and action limits (AL) that could be adopted in clinical practice.</p><p><strong>Materials and methods: </strong>PSQA was performed for 67 head and neck (H&N) and 69 prostate treatment plans, using an appropriate phantom and the γ-index method. The 3%/2  mm acceptance criterion was used. Treatment plans' 2D% GP and 3D %GP values were collected and correlated with individual 3D %GP values of planning target volume (PTV) and organs at risk (OARs). Institutional TL and AL of both 2D %GP and 3D %GP were established using 30 prostate and 30 H&N treatment plans, as per recommendations proposed by AAPM TG-218.</p><p><strong>Results: </strong>A moderate correlation was observed between 2D %GP and 3D %GP of the treatment plans. Τhe correlations demonstrated a stronger association for the 3D %GP than for the 2D %GP with respect to the 3D %GP of the individual structures considered. The TL for the 3D %GP (both plan and individual) and the plans' 2D %GP were generally more stringent, while the AL showed a wider range compared to the corresponding limits suggested by the TG-218 protocol for plan 2D %GP.</p><p><strong>Conclusions: </strong>Institution-specific 3D %GP as well as TL and AL for treatment plan, PTV and OARs could be incorporated in the PSQA procedure in synergy with the 2D evaluation, as they can provide a more-in-depth-view of the treatment quality.</p>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":" ","pages":"e70025"},"PeriodicalIF":2.0,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143448856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}