Journal of Applied Clinical Medical Physics最新文献

{"title":"The effect of multi-leaf collimator leaf width on VMAT treatment plan quality","authors":"Gregory Sadharanu Peiris, Brendan Whelan, Nicholas Hardcastle, Suzie Lynn Sheehy","doi":"10.1002/acm2.70018","DOIUrl":"10.1002/acm2.70018","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>The advent of volumetric modulated arc therapy (VMAT) in radiotherapy has made it one of the most commonly used techniques in clinical practice. VMAT is the delivery of intensity modulated radiation therapy (IMRT) while the gantry is in motion, and existing literature has shown it has decreased treatment delivery times and the number of monitor units without sacrificing coverage. It has previously been shown that for IMRT, multi-leaf collimators (MLC) with narrower leaf widths produce demonstrably higher treatment plan quality. However, as VMAT is rapidly becoming the global standard, this needs to be re-evaluated, especially in a global context. This study assesses the impact of MLC leaf width on VMAT treatment plans and asks whether reducing the number of leaves- and thus increasing leaf width- provides clinically acceptable treatment plans using VMAT delivery.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Material & methods</h3>\u0000 \u0000 <p>Using Varian Eclipse, 51 anonymised patients with prostate, lung, liver, colorectal, or cervical cancer had VMAT treatment plans generated. Treatment plans were generated for MLC leaf widths of 2.5, 5 and 10 mm. Plans were compared using <i>D</i><sub>2</sub>[%], <i>D</i><sub>50</sub>[%], and <i>D</i><sub>98</sub>[%], homogeneity index (HI), conformity index (CI), average leaf pair opening (ALPO), modulation factor (MF) and Estimated Treatment Delivery Time.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The dose to the target structures showed little difference between 2.5 and 5 mm MLC leaves, however 10 mm MLC provided 5% more median dose than the narrower leaf widths for <i>D</i><sub>2</sub>[%] (<i>p</i> < 0.05) and <i>D</i><sub>50</sub>[%] (<i>p</i> < 0.05). The average HI per leaf width was 0.0777 for 2.5 mm, 0.0752 for 5 mm, and 0.0890 for 10 mm. Organs At Risk (OAR) sparing was consistent between all leaf widths except at low dose percentages, where 10 mm MLC delivered an extra dose to the bladder (<i>p</i> < 0.05) and the heart (<i>p</i> < 0.05). The average ALPO was 38.0 mm for 2.5 mm, 34.1 mm for 5 mm, and 32.7 mm for 10 mm leaf width. 10 mm MLC leaves traveled a shorter distance from the center (<i>p</i> < 0.05). The median MF was 336 MU/Gy for 2.5 mm, 344 MU/Gy for 5 mm, and 384 MU/Gy for 10 mm. There were no differences in estimated treatment delivery time between MLC leaf width.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>There is little difference in treatment quality between any of the investigated MLC leaf widths. This work demonstrates that for VMAT treat","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 5","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70018","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143624602","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":"High spatial resolution dosimetry for radiation oncology with “MagicPlates,” a new 976-pixel monolithic silicon detector","authors":"Ilia Filipev,&nbsp;Saree Alnaghy,&nbsp;Martin Carolan,&nbsp;Jason Paino,&nbsp;Marco Petasecca,&nbsp;Dean Cutajar,&nbsp;Joel Poder,&nbsp;Justin B. Davies,&nbsp;Bradley M. Oborn,&nbsp;Nicholas Hardcastle,&nbsp;Susanna Guatelli,&nbsp;Michael Lerch,&nbsp;Tomas Kron,&nbsp;Anatoly Rosenfeld","doi":"10.1002/acm2.70015","DOIUrl":"10.1002/acm2.70015","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>We introduce the next generation of “MagicPlate” 2D monolithic pixelated semiconductor detectors – MagicPlate-976 (MP976). It features a larger array area, higher spatial resolution, and does not require external triggering. We perform a comprehensive characterization for small-field steep-dose-gradient dosimetry applications in radiation therapy focusing on x-ray beams used in stereotactic treatments.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>The MP976, developed by the Centre for Medical Radiation Physics, consists of 976 ion-implanted diodes on a thin n-type epitaxial silicon substrate with a total array area of 58 × 58 mm². The central region has “small” diodes with an area of 0.2 × 0.2 mm² and 1 mm pitch and the peripheral region has “large” diodes with an area of 0.6 × 0.6 mm² and 2 mm pitch. The detector was primed with 10 kGy (Co-60) and tested using a Varian TrueBeam linear accelerator for sensitivity change and dose linearity, and variations in response due to dose-per-pulse and beam incidence angle. Output factors, depth dose, and beam profiles were measured and compared with reference data.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>After the 10 kGy, the sensitivity declined by (74 ± 5)% for “large” diodes and by (78 ± 7)% for the “small” ones, the dose-per-pulse (DPP) dependence was in the range of commercially available diodes, however, a difference in the DPP dependence between the “large” and “small” diodes of (8.4 ± 0.2)% was found in the studied DPP range from 0.131–1.111 mGy/pulse. The minimum angular response was at 90° for 6 MV and 100° for 10 MV flattened beams (76% and 82%, respectively). The output factors and depth dose response showed agreement with the reference within 3.1% and 1%, respectively. Deviation in small field 80%/20% penumbra measurements was within 0.5 mm for 6 MV FF and 0.3 mm for 10 MV FFF. Full width at half maximum (FWHM) for the beam profiles agreed within 0.5 mm for both beam qualities.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>The new MagicPlate-976 detector system is shown to be suitable for dosimetry in small fields and steep dose gradients. It provides 1 mm spatial resolution in the central region and 2 mm on the periphery and has no dependence on the field size. The system's high spatial and temporal resolution opens new opportunities for trigger-less, film-less, and time-resolved verification and error identification for complex stereotactic treatment plans.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 4","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70015","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143624597","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 effect of silicone-based gel on skin surface during volumetric modulated arc therapy for breast cancer.","authors":"Tenyoh Suzuki, Shingo Ohira, Mami Ogita, Takeshi Ohta, Yuki Nozawa, Masanari Minamitani, Takuya Hayashi, Shigeki Saegusa, Toshikazu Imae, Tsuyoshi Ueyama, Atsuto Katano, Hideomi Yamashita, Weishan Chang, Keiichi Nakagawa","doi":"10.1002/acm2.70070","DOIUrl":"https://doi.org/10.1002/acm2.70070","url":null,"abstract":"<p><strong>Purpose: </strong>This study aims to quantify and compare the dosimetric effects of varying thicknesses of StrataXRT, a silicone-based gel, and other topical agents on the skin surface during volumetric modulated arc therapy (VMAT) for breast cancer.</p><p><strong>Methods: </strong>A VMAT plan was created for breast cancer treatment using a female RANDO phantom with a prescription dose of 50 Gy in 25 fractions. The planning target volume (PTV) encompassed the left breast and the regional lymph nodes. Irradiation was performed using a 6 MV photon beam. Three topical agents (StrataXRT, Hirudoid Soft Ointment, and RINDERON-Vs Ointment) having eight thicknesses (0.0-1.5 mm) were evaluated. Dosimetry was conducted using Gafchromic EBT4 films at three anatomical locations-subclavicular, medial, and lateral aspects of the left breast.</p><p><strong>Results: </strong>Mean dose enhancement ratios (DERs) of 102%-116% were observed in VMAT for topical agent thicknesses of 0.1-0.5 mm, increasing to 116%-126% at 1.0 and 1.5 mm. Among the evaluated agents, StrataXRT consistently exhibited the lowest DER, with a statistically significant difference (p < 0.05).</p><p><strong>Conclusions: </strong>This study demonstrated that StrataXRT exhibited the lowest DER among the evaluated topical agents in VMAT for breast cancer. Thicknesses exceeding 0.5 mm potentially exceeded the threshold dose for acute skin reactions.</p>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":" ","pages":"e70070"},"PeriodicalIF":2.0,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143624593","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":"Methods for working with problem residents in medical physics residency education","authors":"Christopher J. Watchman,&nbsp;Dandan Zheng","doi":"10.1002/acm2.70068","DOIUrl":"10.1002/acm2.70068","url":null,"abstract":"<p>Medical physics residency training programs may occasionally encounter residents requiring additional intervention beyond normal training efforts. In the literature, these residents are referred to as “problem” residents. While the physician literature on the subject is valuable, this paper specifically focuses on dealing with a problem medical physics resident. This work discusses a generalized strategy for addressing and correcting medical physics problem resident issues. A discussion of categories of problems that may be encountered is also presented. Additionally, a standardized process for resident intervention is given, along with a discussion of issues related to transparency and bias. Applying the principles in this work should assist medical physics residency programs in establishing a strong culture where all residents, including those experiencing difficulties, can successfully complete their medical physics residency training. This work is a result of collaborations facilitated by the Society of Directors of Academic Medical Physics Programs (SDAMPP).</p>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 5","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70068","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143624601","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":"AAPM-RSS Medical Physics Practice Guideline 9.b: SRS-SBRT","authors":"Eileen Cirino,&nbsp;Stanley H. Benedict,&nbsp;Pamela J. Dupre,&nbsp;Per H. Halvorsen,&nbsp;Grace Gwe-Ya Kim,&nbsp;Meral L. Reyhan,&nbsp;Christopher W. Schneider,&nbsp;Lei Wang,&nbsp;Carl P. Weaver,&nbsp;Sua Yoo","doi":"10.1002/acm2.14624","DOIUrl":"10.1002/acm2.14624","url":null,"abstract":"<p>The purpose of this Medical Physics Practice Guideline (MPPG) is to describe the minimum level of medical physics support deemed prudent for the practice of linear-accelerator, photon-based (linac) stereotactic radiosurgery (SRS), and stereotactic body radiation therapy (SBRT) services. This report is an update of MPPG 9.a¹ published in 2017. As SRS and SBRT services are rapidly adopted into the community-practice setting, this guideline has been developed to build on the work presented in MPPG 9.a and provide current appropriate minimum practice guidelines for such services.</p>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 4","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.14624","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143604827","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":"AAPM Medical Physics Practice Guideline MPPG 17.a: Quality management for mammography review workstation displays","authors":"Rebecca Milman,&nbsp;Nicholas B. Bevins,&nbsp;Mosa Alhamami,&nbsp;Nathan Busse,&nbsp;Andreea Dohatcu,&nbsp;Katie W. Hulme,&nbsp;Mary Ellen Jafari,&nbsp;Steven M. LaFontaine,&nbsp;Richard D. Nawfel,&nbsp;Jeffrey S. Nelson,&nbsp;Megan K. Russ,&nbsp;Michael Silosky,&nbsp;John M. Wait","doi":"10.1002/acm2.14625","DOIUrl":"10.1002/acm2.14625","url":null,"abstract":"<p>The Mammography Quality Standards Act (MQSA) sets quality standards for displays used to interpret mammography images. With the shift to digital mammography and the widespread use of remote reading workstations (RWS), updated quality management (QM) programs are needed to ensure consistent image presentation and accurate interpretation. This document recommends a QM framework for mammography RWS displays, addressing challenges such as remote environments, regulatory compliance, and evolving technology. The QM model highlights the central role of medical physicists in program design, oversight, and data review. It emphasizes periodic quality assurance (QA) and quality control (QC) procedures and training for interpreting physicians and staff. A structure for QM for remote RWS, including guidance on environmental conditions, hands-on testing, and remote monitoring solutions, is included. The proposed program balances scientific rigor, cost-effectiveness, and practical implementation, maintaining image quality and safety. By providing a structured approach to RWS display management, this framework supports regulators, accreditation bodies, and healthcare facilities in adapting to advancements in mammography technology while addressing logistical and operational challenges.</p>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 4","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.14625","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143604803","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":"Bone-wise rigid registration of femur, tibia, and fibula for the tracking of temporal changes","authors":"Arttu Ruohola,&nbsp;Ville Haapamäki,&nbsp;Eero Salli,&nbsp;Tuomas Kaseva,&nbsp;Marko Kangasniemi,&nbsp;Sauli Savolainen","doi":"10.1002/acm2.70053","DOIUrl":"10.1002/acm2.70053","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Multiple myeloma (MM) induces temporal alterations in bone structure, such as osteolytic bone lesions, which are challenging to identify through manual image interpretation. The large variation in radiologists' assessments, even at expert centers, further complicates diagnosis. Automatic image analysis methods, including segmentation and registration, can expedite detecting and tracking these bone changes.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>This study presents an automated pipeline for accurately tracking temporal changes in the femurs, tibiae, and fibulae of MM patients using 3D whole-body CT images. The pipeline leverages image segmentation, rigid registration, and temporal subtraction to accelerate disease monitoring and support clinical decision-making.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>A convolutional neural network (CNN) was trained to segment bones in 3D CT images of 30 MM patients. Nine patients with pre- and post-diagnosis CT scans were used to validate the segmentation and registration process. A two-phase bone-wise rigid registration was applied, followed by temporal subtraction to generate difference images. Segmentation and registration accuracy were assessed using the Dice similarity coefficient (DSC) and mean surface distance (MSD). The proposed method was compared to a non-rigid registration method.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The neural network segmentation resulted in a mean DSC of 0.93 across all bone types and all test data. The registration accuracy measured by the mean DSC across the test data was at least 0.94 for all bone types. The second phase of rigid registration improved the registration fibulae. Metric-wise, the nonrigid method performed better but diminished lesion visibility in difference images.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>An automated pipeline for the longitudinal tracking of bone alterations was presented. Both segmentation and registration demonstrated high accuracy as measured by DSC and MSD. In the difference images produced by temporal subtraction, osteolytic lesions were clearly visible in the femurs. The methodology lays a solid foundation for future improvements, such as inclusion of the axial spine.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 5","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70053","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143604828","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":"Commissioning a standalone adaptive radiotherapy linac in a multi-vendor environment","authors":"Sven Olberg,&nbsp;David M. McClatchy 3rd,&nbsp;Colleen Foote,&nbsp;Susu Yan,&nbsp;Jennifer Pursley","doi":"10.1002/acm2.70033","DOIUrl":"10.1002/acm2.70033","url":null,"abstract":"<p>Current radiotherapy machines intended to perform streamlined online adaptive therapy are designed to be standalone, which makes it challenging to integrate them with the rest of the clinic. This work describes the installation of a standalone CT-guided online adaptive system, the Varian Ethos, in a busy clinic utilizing products from multiple vendors, including RayStation as the treatment planning system (TPS) and MOSAIQ as the oncology information system (OIS). The aim was to develop solutions that minimized workload increases for staff using redundant systems and to implement this new technology safely, with no increase in safety reports resulting from its integration into the clinic. The Ethos was delivered with a pre-configured beam model, and a separate Ethos beam model was developed in RayStation 10A. Non-adaptive treatments were planned in RayStation and transferred to Ethos for delivery. Although MOSAIQ 2.64 could not communicate with the Ethos, a machine characterization file was developed to allow manual recording of the treatment fields in MOSAIQ. Online adaptive therapy was performed using the Ethos TPS and OIS with documentation in MOSAIQ. Although dose calculations of the same plans differed by 1%–2% in the pelvis in RayStation compared to the Ethos TPS, dose computed in both systems passed measurement-based QA, end-to-end testing, and clinical trial credentialing, so both systems were commissioned for clinical use. RayStation plans were successfully modified for delivery on Ethos, and at go-live, all non-adaptive planning was performed in RayStation and adaptive planning in Ethos. Ethos treatments were documented in MOSIAQ, which remained the OIS of record for all patients. Monitoring of error reports indicated some unique failure modes to the new technology, but the overall number of safety reports remained comparable to other systems. In conclusion, Ethos was successfully deployed for both non-adaptive and online adaptive therapy in a multi-vendor environment.</p>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"26 4","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70033","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143596896","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":"Multi-institutional study on image quality for a novel CBCT solution on O-ring linac.","authors":"Luis Agulles-Pedrós, R Lee MacDonald, Amanda Jean Cherpak, Nayha Dixit, Lei Dong, Tianyu Zhao, Kundan Thind, Anthony Doemer, Boon-Keng Teo, Shiqin Su, Alexander Moncion, James L Robar","doi":"10.1002/acm2.70023","DOIUrl":"https://doi.org/10.1002/acm2.70023","url":null,"abstract":"<p><strong>Introduction: </strong>This work presents a multi-institutional study on image quality provided by a novel cone beam computed tomography (CBCT). The main goal is to investigate the consistency of imaging performance across multiple institutions.</p><p><strong>Methods: </strong>Phantoms for measuring relative electron density (RED) and image quality were sent to six institutions for imaging on Ethos and Halcyon units equipped with HyperSight CBCT. The imaging protocols included tube potential from 100 to 140 kVp and exposure from 80 to 800 mAs. Imaging performance was evaluated with regard to RED versus Hounsfield units (HU), uniformity, contrast-to-noise ratio (CNR), slice thickness, circular symmetry, modulation transfer function (MTF), and spatial resolution.</p><p><strong>Results: </strong>Among all institutions, some variability was observed among institutions in the RED-to-HU relationship, especially for RED values greater than 1, although no outliers were found (|z-score| < 2 in all cases). In this range, RED/HU slopes were 475 ± 25 10^-6 RED/HU at 100kVp, 505 ± 20 10^-6 RED/HU at 125kVp, and 550 ± 20 10^-6 RED/HU at 140kVp. Radial uniformity ranged from 1 to 7 HU, depending on protocol. Circular symmetry for two points 50 mm apart showed consistency within one-pixel dimension. Integral nonuniformity was between 1 and 10, with no difference observed between vertical and horizontal dimensions. Contrast rods with 1% gave CNR = 0.5, 1 and 2 for 100(88), 125(176), and 140(528) in kVp(mAs), and contrast rods with 0.5% had CNR = 0.2, 0.4 and 0.8 for 100(88), 125(176), and 140(528) in kVp(mAs). Spatial resolution given by MTF at 10% and 50% yielded values of 0.55 ± 0.01 mm^-1 and 0.35 ± 0.02 mm^-1, respectively.</p><p><strong>Conclusions: </strong>This multi-institutional analysis of CBCT imaging performance showed consistency in radial uniformity, circular symmetry, integral nonuniformity, contrast, and spatial resolution. Some variability was seen in the RED-to-HU relationship for RED > 1 depending on exposure. More data from different institutions would be necessary to establish more robust statistical metrics, which ensure quality parameters.</p>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":" ","pages":"e70023"},"PeriodicalIF":2.0,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143573034","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":"Stereotactic radiotherapy for metastatic brain tumors: A comparative analysis of dose distributions among VMAT, Helical TomoTherapy, CyberKnife, Gamma Knife, and ZAP-X.","authors":"Toshihiro Suzuki, Masahide Saito, Ryutaro Nomura, Hikaru Nemoto, Naoto Yanagisawa, Ryuma Sawada, Zennosuke Mochizuki, Naoki Sano, Hiroshi Onishi, Hiroshi Takahashi","doi":"10.1002/acm2.70046","DOIUrl":"https://doi.org/10.1002/acm2.70046","url":null,"abstract":"<p><p>This study evaluates various radiotherapy techniques for treating metastatic brain tumor (BT), focusing on non-coplanar volumetric modulated arc radiotherapy (NC-VMAT), coplanar VMAT (C-VMAT), Helical TomoTherapy (HT), CyberKnife (CK), Gamma Knife (GK), and ZAP-X. CT images and structures of 12 patients who underwent CK for a single BT were utilized. Twelve treatment plans were created for each planning device. All plans adopted the approach of prescription doses to planning target volume D99.5%. They were divided into stereotactic radiosurgery (SRS) (prescription dose; 21-23 Gy) and stereotactic radiotherapy (SRT) (prescription dose; 30-36.5 Gy) groups and the same parameters evaluated included Gradient Index (GI), Paddick Conformity Index (CI), and treatment time (t-time). In the SRS group, mean values of GI and CI values were: NC-VMAT (4.28, 0.60), C-VMAT (5.61, 0.44), HT (4.68, 0.42), CK (4.31, 0.61), GK (2.81, 0.82), and ZAP-X (2.99, 0.80). In the SRT group: NC-VMAT (3.27, 0.84), C-VMAT (3.81, 0.82), HT (3.76, 0.65), CK (2.98, 0.77), GK (2.61, 0.90), and ZAP-X (2.80, 0.84). There were no significant differences in the mean values of CI and GI between ZAP-X and GK in both groups (p > 0.05). NC-VMAT and C-VMAT had shorter t-time than other techniques in both groups. ZAP-X is relatively superior in CI and GI for small tumors, similar to GK, while differences with NC-VMAT and CK diminish as tumor volume increases. ZAP-X, CK, and GK have longer t-time than other treatment techniques, regardless of volume.</p>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":" ","pages":"e70046"},"PeriodicalIF":2.0,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143556890","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}