Colin J. Schaeffer, Katie W. Hulme, Ashley E. Rubinstein
Background
Digital breast tomosynthesis (DBT) has become standard practice; however, the acquisition method of DBT between vendors is far from standardized. Currently, there are three commercially available DBT tube motion techniques: (1) continuous motion, (2) step-and-shoot, and (3) continuous motion with flying focal spot. Each of these methods represents a trade-off between total acquisition time and focal spot blur.
Purpose
The aim of the study was to characterize the increase in effective focal spot size in DBT relative to standard 2D projections and assess the influence of this increase on spatial resolution using the modulation transfer function (MTF).
Methods
Focal spot size was measured for both a 2D acquisition and the 0° DBT projection using a 10 µm slit phantom. Imaging techniques were set to those used for a 2, 4, and 8 cm thick breast of 50/50 adipose/fat composition. MTF curves were measured using a copper edge phantom both at the breast support plane and 4 cm above the breast support.
Results
The effective focal spot size increase from 2D to DBT increased with breast thickness for all systems. The continuous motion systems showed the greatest increase in effective focal spot size with percent increases of 101% to 462% depending on unit and breast thickness. The flying focal spot system showed the smallest increase in effective focal spot size in DBT acquisitions, being 3%, 21%, and 25% for a 2, 4, and 8 cm thick breast, respectively. The step-and-shoot and flying focal spot systems showed no degradation in MTF curves due to increasing effective focal spot size in DBT acquisitions, while the continuous motion systems showed a reduction in the frequency at which the MTF curve reached 50% of 26%–45%.
Conclusion
Both step-and-shoot and flying focal spot systems minimized effective focal spot size increase in DBT acquisitions compared to continuous tube motion systems.
{"title":"Focal spot motion in digital breast tomosynthesis and its effect on spatial resolution","authors":"Colin J. Schaeffer, Katie W. Hulme, Ashley E. Rubinstein","doi":"10.1002/acm2.70443","DOIUrl":"10.1002/acm2.70443","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Digital breast tomosynthesis (DBT) has become standard practice; however, the acquisition method of DBT between vendors is far from standardized. Currently, there are three commercially available DBT tube motion techniques: (1) continuous motion, (2) step-and-shoot, and (3) continuous motion with flying focal spot. Each of these methods represents a trade-off between total acquisition time and focal spot blur.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>The aim of the study was to characterize the increase in effective focal spot size in DBT relative to standard 2D projections and assess the influence of this increase on spatial resolution using the modulation transfer function (MTF).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Focal spot size was measured for both a 2D acquisition and the 0° DBT projection using a 10 µm slit phantom. Imaging techniques were set to those used for a 2, 4, and 8 cm thick breast of 50/50 adipose/fat composition. MTF curves were measured using a copper edge phantom both at the breast support plane and 4 cm above the breast support.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The effective focal spot size increase from 2D to DBT increased with breast thickness for all systems. The continuous motion systems showed the greatest increase in effective focal spot size with percent increases of 101% to 462% depending on unit and breast thickness. The flying focal spot system showed the smallest increase in effective focal spot size in DBT acquisitions, being 3%, 21%, and 25% for a 2, 4, and 8 cm thick breast, respectively. The step-and-shoot and flying focal spot systems showed no degradation in MTF curves due to increasing effective focal spot size in DBT acquisitions, while the continuous motion systems showed a reduction in the frequency at which the MTF curve reached 50% of 26%–45%.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>Both step-and-shoot and flying focal spot systems minimized effective focal spot size increase in DBT acquisitions compared to continuous tube motion systems.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12788966/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145944034","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}
Carlos Ferrer, Concepción Huertas, Marcos Feijoo, Alessandro Cardin, Moisés Sáez
Background
Plastic scintillation detectors (PSD) are widely used for detecting and measuring ionizing radiation. These detectors are versatile, with high efficiency, fast response and the ability to provide real-time measurements.
Purpose
Evaluate the suitability of Blue Physics PSD (BP-PSD) for performing ultra-fast dosimetric commissioning measurements with high accuracy and precision in a very short time.
Methods
Ultra-fast measurements were performed in water using a BP-PSD on an Elekta Unity MR-linac. Percentage depth doses (PDD) and profiles at different depths were measured at two movement velocities, 10 mm/s and 20 mm/s, for field sizes ranging from 10 × 10 cm2 to 1 × 1 cm2. Gamma analysis was conducted to compare these measurements with those obtained during machine commissioning using a PTW Semiflex 3D ionization chamber (for PDD) and a PTW micro-Diamond detector (for PDD and profiles). Gamma criteria of 2%/2 mm and 1%/1 mm dose difference/distance to agreement were studied, alongside field size, penumbra, and measurement time.
Results
All PDD and profile gamma passing rates were 100% at 2%/2 mm. At the stricter 1%/1 mm criteria, all PDD showed a passing rate above 96.97% for both velocities, with most of the profiles exceeding 95% at 10 mm/s and 90% at 20 mm/s. Gamma analysis results were superior for smaller fields (1 × 1 cm2 and 2 × 2 cm2) and generally better at 10 mm/s. On average, the penumbra measurements obtained with the PSD were greater than those achieved with the micro-Diamond detector. Measurement times were found to be between 7 and 14 times shorter for PDD, and between 5 and 9 times shorter for profiles at speeds of 10 mm/s and 20 mm/s, respectively.
Conclusions
Ultra-fast measurements using the Blue Physics PSD are suitable for acquiring dosimetric commissioning data with high accuracy and precision, and can be performed in a much shorter timeframe than with commonly used detectors.
{"title":"Ultra-fast dosimetric data collection with a commercial plastic scintillation detector in an MR-linac","authors":"Carlos Ferrer, Concepción Huertas, Marcos Feijoo, Alessandro Cardin, Moisés Sáez","doi":"10.1002/acm2.70460","DOIUrl":"10.1002/acm2.70460","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Plastic scintillation detectors (PSD) are widely used for detecting and measuring ionizing radiation. These detectors are versatile, with high efficiency, fast response and the ability to provide real-time measurements.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>Evaluate the suitability of Blue Physics PSD (BP-PSD) for performing ultra-fast dosimetric commissioning measurements with high accuracy and precision in a very short time.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Ultra-fast measurements were performed in water using a BP-PSD on an Elekta Unity MR-linac. Percentage depth doses (PDD) and profiles at different depths were measured at two movement velocities, 10 mm/s and 20 mm/s, for field sizes ranging from 10 × 10 cm<sup>2</sup> to 1 × 1 cm<sup>2</sup>. Gamma analysis was conducted to compare these measurements with those obtained during machine commissioning using a PTW Semiflex 3D ionization chamber (for PDD) and a PTW micro-Diamond detector (for PDD and profiles). Gamma criteria of 2%/2 mm and 1%/1 mm dose difference/distance to agreement were studied, alongside field size, penumbra, and measurement time.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>All PDD and profile gamma passing rates were 100% at 2%/2 mm. At the stricter 1%/1 mm criteria, all PDD showed a passing rate above 96.97% for both velocities, with most of the profiles exceeding 95% at 10 mm/s and 90% at 20 mm/s. Gamma analysis results were superior for smaller fields (1 × 1 cm<sup>2</sup> and 2 × 2 cm<sup>2</sup>) and generally better at 10 mm/s. On average, the penumbra measurements obtained with the PSD were greater than those achieved with the micro-Diamond detector. Measurement times were found to be between 7 and 14 times shorter for PDD, and between 5 and 9 times shorter for profiles at speeds of 10 mm/s and 20 mm/s, respectively.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Ultra-fast measurements using the Blue Physics PSD are suitable for acquiring dosimetric commissioning data with high accuracy and precision, and can be performed in a much shorter timeframe than with commonly used detectors.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12779937/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145917694","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}
This study aimed to establish a framework for optimizing planning target volume (PTV) margins in liver SBRT using virtual 4DCT (v4DCT), by introducing the concept of the Dosimetric Coverage Amplitude (DCA) to quantify motion tolerance and deriving an Optimal Margin (OM) that balances tumor coverage with normal-tissue sparing.
Methods
VMAT plans were developed using a whole-body phantom with a virtual tumor, ensuring that the prescription dose corresponded to D95% of the PTV. The 60%–80% isodose levels were defined relative to the maximum dose to represent alternative prescription surfaces. v4DCT simulated free-breathing conditions across 10 respiratory phases to generate virtual four-dimensional radiotherapy (v4DRT) dose distributions. The DCA was defined as the maximum respiratory amplitude at which GTV dose coverage (D100% or D99%) was maintained. Based on DCA analysis, the OM was determined as the clinically applicable margin derived from the isodose plan that satisfied the DCA condition and minimized normal tissue dose.
Results
DCA analysis revealed that GTV dose coverage was maintained for respiratory motion amplitudes up to 1.9–2.2 times larger than the conventional PTV margin of 10 mm. Taking into account GTV dose coverage, average GTV dose relative to the 80%-static reference, and normal-tissue dose, the 60% isodose plan was identified as the optimal prescription level. From this plan, the OM was calculated as 5.6 mm, representing a 44% reduction compared with the conventional 10-mm PTV, while maintaining GTV coverage and minimizing liver dose. This margin reduction was attributed to the steeper dose gradient associated with prescribing to a lower isodose level. The v4DCT approach enabled the generation of multiple respiratory phase images, allowing quantitative evaluation of motion-induced dose distribution and optimization of margins based on respiratory variability.
Conclusion
The proposed v4DCT-based framework demonstrated that the 60% isodose plan provided the optimal balance between tumor coverage and normal-tissue sparing, yielding an OM of 5.6 mm (44% reduction compared with the conventional 10-mm PTV). This approach offers a clinically applicable strategy for margin reduction in liver SBRT while maintaining robust dosimetric coverage.
目的：本研究旨在通过引入剂量覆盖幅度（DCA）的概念来量化运动耐受性，并得出平衡肿瘤覆盖与正常组织保留的最佳边界（OM），建立一个使用虚拟4DCT （v4DCT）优化肝脏SBRT规划靶体积（PTV）边界的框架。方法：采用带虚拟肿瘤的全身假体制定VMAT计划，确保处方剂量符合PTV的D95%。60%-80%等剂量水平被定义为相对于最大剂量来代表可选择的处方表面。v4DCT模拟10个呼吸期的自由呼吸条件，生成虚拟四维放疗（v4DRT）剂量分布。DCA定义为维持GTV剂量覆盖（D100%或D99%）时的最大呼吸振幅。根据DCA分析，确定OM为满足DCA条件和最小正常组织剂量的等剂量方案得出的临床适用边界。结果：DCA分析显示，GTV对呼吸运动幅度的剂量覆盖范围比常规PTV的10 mm大1.9-2.2倍。综合考虑GTV剂量覆盖率、相对于80%静态参考的平均GTV剂量和正常组织剂量，确定60%等剂量计划为最佳处方水平。根据该方案，OM计算为5.6 mm，与传统的10 mm PTV相比减少了44%，同时保持GTV覆盖范围并使肝脏剂量最小化。这种边际减少归因于与较低等剂量水平处方相关的更陡峭的剂量梯度。v4DCT方法能够生成多个呼吸期图像，允许定量评估运动引起的剂量分布和基于呼吸变异性的边缘优化。结论：提出的基于v4dct的框架表明，60%等剂量计划提供了肿瘤覆盖和正常组织保留之间的最佳平衡，产生5.6 mm的OM（与传统的10 mm PTV相比减少44%）。该方法提供了一种临床适用的策略，可以在保持稳健剂量覆盖的同时减少肝脏SBRT的边缘。
{"title":"Margin reduction and optimal prescription isodose model for liver stereotactic radiotherapy with respiratory motion","authors":"Daisuke Kawahara, Hirokazu Masuda, Takuya Wada, Misato Kishi, Tsuyoshi Katsuta, Yuji Murakami","doi":"10.1002/acm2.70455","DOIUrl":"10.1002/acm2.70455","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>This study aimed to establish a framework for optimizing planning target volume (PTV) margins in liver SBRT using virtual 4DCT (v4DCT), by introducing the concept of the Dosimetric Coverage Amplitude (DCA) to quantify motion tolerance and deriving an Optimal Margin (OM) that balances tumor coverage with normal-tissue sparing.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>VMAT plans were developed using a whole-body phantom with a virtual tumor, ensuring that the prescription dose corresponded to D<sub>95%</sub> of the PTV. The 60%–80% isodose levels were defined relative to the maximum dose to represent alternative prescription surfaces. v4DCT simulated free-breathing conditions across 10 respiratory phases to generate virtual four-dimensional radiotherapy (v4DRT) dose distributions. The DCA was defined as the maximum respiratory amplitude at which GTV dose coverage (D100% or D99%) was maintained. Based on DCA analysis, the OM was determined as the clinically applicable margin derived from the isodose plan that satisfied the DCA condition and minimized normal tissue dose.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>DCA analysis revealed that GTV dose coverage was maintained for respiratory motion amplitudes up to 1.9–2.2 times larger than the conventional PTV margin of 10 mm. Taking into account GTV dose coverage, average GTV dose relative to the 80%-static reference, and normal-tissue dose, the 60% isodose plan was identified as the optimal prescription level. From this plan, the OM was calculated as 5.6 mm, representing a 44% reduction compared with the conventional 10-mm PTV, while maintaining GTV coverage and minimizing liver dose. This margin reduction was attributed to the steeper dose gradient associated with prescribing to a lower isodose level. The v4DCT approach enabled the generation of multiple respiratory phase images, allowing quantitative evaluation of motion-induced dose distribution and optimization of margins based on respiratory variability.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>The proposed v4DCT-based framework demonstrated that the 60% isodose plan provided the optimal balance between tumor coverage and normal-tissue sparing, yielding an OM of 5.6 mm (44% reduction compared with the conventional 10-mm PTV). This approach offers a clinically applicable strategy for margin reduction in liver SBRT while maintaining robust dosimetric coverage.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12779934/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145917653","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}
Christopher M. Walker, Maria G. Maldonado, Megan C. Jacobsen, Suprateek Kundu, Michelle L. Underwood, Joshua P. Yung, Brandy J. Reed, David Jaffray, R. Jason Stafford, Marshall E. Hicks, Caroline Chung, Aradhana M. Venkatesan
Background
As medical imaging demand grows, there is increasing stress on the currently available workforce to deliver consistent, high-quality imaging studies while ensuring rapid study turnaround times and round-the-clock radiology coverage. Advances in remote access technology facilitating remote scan assistance and control are now commercially available to address these pressing clinical needs.
Methods
This work evaluated an early clinical application of a virtual scanner operations system (syngo Virtual Cockpit (VA13A, Siemens Healthineers, Erlangen, Germany) for remote magnetic resonance imaging (MRI) monitoring and scan control at three geographically distant outpatient sites associated with our primary institution.
Results
The system facilitated execution of technically complex oncologic MRI exams at these geographically distant clinics with no measurable impact on acquisition time compared to MR imaging performed at our primary hospital location. Additional operational improvements were realized with the use of the system, including remote staff training, technical assistance, and scanning during staff shortages. This early iteration of remote scanning had some limitations including limited utility for additional assistance in the scanning of those protocols that require complex physical setup. Moreover, connectivity issues were noted to be a limiting factor that contributed to operational delays. It was still necessary to have an onsite MRI technologist at the scanner console to interface with the patient and ensure safe operation.
Conclusion
Despite these limitations, our initial experience demonstrates that the use of remote MRI scanning support facilitates staffing flexibility while providing expanded patient access to oncology MRI services.
{"title":"Initial experience with remote MRI scanning support in an oncology focused practice: Opportunities for expanded access to radiology care","authors":"Christopher M. Walker, Maria G. Maldonado, Megan C. Jacobsen, Suprateek Kundu, Michelle L. Underwood, Joshua P. Yung, Brandy J. Reed, David Jaffray, R. Jason Stafford, Marshall E. Hicks, Caroline Chung, Aradhana M. Venkatesan","doi":"10.1002/acm2.70461","DOIUrl":"10.1002/acm2.70461","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>As medical imaging demand grows, there is increasing stress on the currently available workforce to deliver consistent, high-quality imaging studies while ensuring rapid study turnaround times and round-the-clock radiology coverage. Advances in remote access technology facilitating remote scan assistance and control are now commercially available to address these pressing clinical needs.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>This work evaluated an early clinical application of a virtual scanner operations system (syngo Virtual Cockpit (VA13A, Siemens Healthineers, Erlangen, Germany) for remote magnetic resonance imaging (MRI) monitoring and scan control at three geographically distant outpatient sites associated with our primary institution.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The system facilitated execution of technically complex oncologic MRI exams at these geographically distant clinics with no measurable impact on acquisition time compared to MR imaging performed at our primary hospital location. Additional operational improvements were realized with the use of the system, including remote staff training, technical assistance, and scanning during staff shortages. This early iteration of remote scanning had some limitations including limited utility for additional assistance in the scanning of those protocols that require complex physical setup. Moreover, connectivity issues were noted to be a limiting factor that contributed to operational delays. It was still necessary to have an onsite MRI technologist at the scanner console to interface with the patient and ensure safe operation.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>Despite these limitations, our initial experience demonstrates that the use of remote MRI scanning support facilitates staffing flexibility while providing expanded patient access to oncology MRI services.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12779931/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145917682","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}
Wenchao Gao, Min Zhang, Shuchao Zhang, Jie Qi, Xin Wang, Liang Zhao, Ping Liu, Zhijun Yang, HongXiang Cheng
<div> <section> <h3> Background</h3> <p>Accurate dose calculations in radiotherapy depend on high-quality beam models in the Monaco treatment planning system (TPS). The accelerated go live (AGL) workflow, using a golden beam data (GBD) model, has improved beam modeling accuracy for various linear accelerators (linacs). However, similar studies specifically for the Harmony Pro, recently introduced for online adaptive radiotherapy, have not yet been reported internationally. Moreover, studies on dosimetric differences between TPS beam models with GBD and those with measured beam data (MBD) are limited, and no such studies have been published specifically for Elekta linacs.</p> </section> <section> <h3> Purpose</h3> <p>This study aimed to assess the clinical performance of GBD in the Monaco TPS for the harmony pro and infinity linacs.</p> </section> <section> <h3> Methods</h3> <p>Beam tuning and data collection were performed on the harmony pro and infinity linacs based on GBD. Subsequently, percentage depth doses (PDDs), off-axis dose profiles, output factors (OFs), absolute doses, and test fields were measured to evaluate the GBD model. Additionally, 31 clinical plans from multiple anatomical sites, including 17 conventional fractionated radiotherapy (CFRT) plans and 14 stereotactic body radiotherapy (SBRT) plans, were designed using the Monaco TPS (GBD model) and practically tested. An Infinity linac with MBD was introduced as a control.</p> </section> <section> <h3> Results</h3> <p>PDDs and profiles on both GBD linacs showed 100% passing rate (2%/2 mm). OFs and absolute doses on both GBD linacs agreed within ±1% and ±1.5%, respectively. Additionally, verification of the test fields yielded passing rates above 98% (2%/2 mm) for both GBD linacs. Furthermore, for CFRT plans, measurements on three linacs achieved a passing rate above 95% (3%/2 mm). The absolute dose deviations were within 3%, whereas one MBD linac case exceeded 3% (-3.73%). For SBRT plans, the gamma passing rates were 98.18 ± 1.58%, 98.76 ± 1.54%, and 94.72 ± 0.04% (3%/2 mm) and 96.69 ± 1.96, 96.29 ± 2.26, and 89.51 ± 0.06% (2%/2 mm), for the two GDB linacs and the MDB linac, respectively. The absolute dose deviations were within 3%, whereas two MBD linac cases exceeded 3% (−3.51%, −4.50%).</p> </section> <section> <h3> Conclusions</h3> <p>The harmony pro-GBD and infinity-GBD linac results demonstrated strong agreement with GBD. Clinical plans designed with Monaco TPS (GBD model) were
{"title":"Clinical evaluation of the golden beam data in the monaco treatment planning system for the harmony pro and infinity linear accelerators","authors":"Wenchao Gao, Min Zhang, Shuchao Zhang, Jie Qi, Xin Wang, Liang Zhao, Ping Liu, Zhijun Yang, HongXiang Cheng","doi":"10.1002/acm2.70457","DOIUrl":"10.1002/acm2.70457","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Accurate dose calculations in radiotherapy depend on high-quality beam models in the Monaco treatment planning system (TPS). The accelerated go live (AGL) workflow, using a golden beam data (GBD) model, has improved beam modeling accuracy for various linear accelerators (linacs). However, similar studies specifically for the Harmony Pro, recently introduced for online adaptive radiotherapy, have not yet been reported internationally. Moreover, studies on dosimetric differences between TPS beam models with GBD and those with measured beam data (MBD) are limited, and no such studies have been published specifically for Elekta linacs.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>This study aimed to assess the clinical performance of GBD in the Monaco TPS for the harmony pro and infinity linacs.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Beam tuning and data collection were performed on the harmony pro and infinity linacs based on GBD. Subsequently, percentage depth doses (PDDs), off-axis dose profiles, output factors (OFs), absolute doses, and test fields were measured to evaluate the GBD model. Additionally, 31 clinical plans from multiple anatomical sites, including 17 conventional fractionated radiotherapy (CFRT) plans and 14 stereotactic body radiotherapy (SBRT) plans, were designed using the Monaco TPS (GBD model) and practically tested. An Infinity linac with MBD was introduced as a control.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>PDDs and profiles on both GBD linacs showed 100% passing rate (2%/2 mm). OFs and absolute doses on both GBD linacs agreed within ±1% and ±1.5%, respectively. Additionally, verification of the test fields yielded passing rates above 98% (2%/2 mm) for both GBD linacs. Furthermore, for CFRT plans, measurements on three linacs achieved a passing rate above 95% (3%/2 mm). The absolute dose deviations were within 3%, whereas one MBD linac case exceeded 3% (-3.73%). For SBRT plans, the gamma passing rates were 98.18 ± 1.58%, 98.76 ± 1.54%, and 94.72 ± 0.04% (3%/2 mm) and 96.69 ± 1.96, 96.29 ± 2.26, and 89.51 ± 0.06% (2%/2 mm), for the two GDB linacs and the MDB linac, respectively. The absolute dose deviations were within 3%, whereas two MBD linac cases exceeded 3% (−3.51%, −4.50%).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The harmony pro-GBD and infinity-GBD linac results demonstrated strong agreement with GBD. Clinical plans designed with Monaco TPS (GBD model) were","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12766699/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145900539","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}
Jessica S. Jung, Lyu Huang, Nicholas Coupera, Yijian Cao, Jenghwa Chang
<div> <section> <h3> Background</h3> <p>Coronary artery disease (CAD), the leading cause of death worldwide, is the narrowing of coronary arteries due to atherosclerotic plaque buildup. A common treatment for CAD is percutaneous coronary intervention (PCI), often involving stent placement. However, a common complication or in-stent restenosis (ISR) can occur in 10%–20% of patients which call for the use of therapies like intravascular brachytherapy (IVBT). IVBT delivers targeted beta radiation, typically from Sr-90/Y-90 sources, to inhibit neointimal hyperplasia and reduce restenosis rates. Accurate dose delivery is critical to treatment success, but challenges such as source positioning and dose uniformity persist. Recent advances in 3D printing and radiochromic film dosimetry offer promising tools for more precise dose verification in IVBT, enabling high-resolution assessment of dose distributions and stent-induced perturbations.</p> </section> <section> <h3> Purpose</h3> <p>IVBT requires precise position to ensure effective treatment. However, stents introduce complexities in dose distribution due to their material and geometry, which can lead to attenuation and impact treatment outcomes. This study aimed to quantify stent-induced dose perturbations using a custom 3D-printed stent phantom and Gafchromic EBT-4 Film, providing insights for dosimetry of IVBT.</p> </section> <section> <h3> Methods</h3> <p>Dose measurements were conducted using a custom designed 3D-printed stent phantom. The film calibration was performed using the RIT film dosimetry package from 0 to 12 Gy. The phantom was designed for a Synergy XD Stent with a diameter of 3 mm with the Sr-90/Y-90 source catheter position designed to be in the center of the stent. Percent depth dose (PDD) distributions were modeled using the third-order exponential polynomial function and compared with Monte Carlo simulations to evaluate agreement. Discrepancies were quantified using root mean square error (RMSE) and mean absolute error (MAE). The stent effect on PDD was analyzed using a paired <i>t</i>-test, and a dose reduction factor (DRF) was calculated to assess attenuation.</p> </section> <section> <h3> Results</h3> <p>The third-order exponential polynomial function demonstrated an excellent fit for both configurations, with R-squared values of 0.999 (no stent) and 0.999 (with stent). RMSE and MAE values were slightly higher for the with-stent dataset (0.038 and 0.036, respectively), reflecting increased discrepancies. The paired <i>t</i>-test showed a statistically significant difference betw
{"title":"Quantifying stent-induced dose perturbations in intravascular brachytherapy using 3D- printed phantoms and film dosimetry","authors":"Jessica S. Jung, Lyu Huang, Nicholas Coupera, Yijian Cao, Jenghwa Chang","doi":"10.1002/acm2.70432","DOIUrl":"10.1002/acm2.70432","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Coronary artery disease (CAD), the leading cause of death worldwide, is the narrowing of coronary arteries due to atherosclerotic plaque buildup. A common treatment for CAD is percutaneous coronary intervention (PCI), often involving stent placement. However, a common complication or in-stent restenosis (ISR) can occur in 10%–20% of patients which call for the use of therapies like intravascular brachytherapy (IVBT). IVBT delivers targeted beta radiation, typically from Sr-90/Y-90 sources, to inhibit neointimal hyperplasia and reduce restenosis rates. Accurate dose delivery is critical to treatment success, but challenges such as source positioning and dose uniformity persist. Recent advances in 3D printing and radiochromic film dosimetry offer promising tools for more precise dose verification in IVBT, enabling high-resolution assessment of dose distributions and stent-induced perturbations.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>IVBT requires precise position to ensure effective treatment. However, stents introduce complexities in dose distribution due to their material and geometry, which can lead to attenuation and impact treatment outcomes. This study aimed to quantify stent-induced dose perturbations using a custom 3D-printed stent phantom and Gafchromic EBT-4 Film, providing insights for dosimetry of IVBT.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Dose measurements were conducted using a custom designed 3D-printed stent phantom. The film calibration was performed using the RIT film dosimetry package from 0 to 12 Gy. The phantom was designed for a Synergy XD Stent with a diameter of 3 mm with the Sr-90/Y-90 source catheter position designed to be in the center of the stent. Percent depth dose (PDD) distributions were modeled using the third-order exponential polynomial function and compared with Monte Carlo simulations to evaluate agreement. Discrepancies were quantified using root mean square error (RMSE) and mean absolute error (MAE). The stent effect on PDD was analyzed using a paired <i>t</i>-test, and a dose reduction factor (DRF) was calculated to assess attenuation.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The third-order exponential polynomial function demonstrated an excellent fit for both configurations, with R-squared values of 0.999 (no stent) and 0.999 (with stent). RMSE and MAE values were slightly higher for the with-stent dataset (0.038 and 0.036, respectively), reflecting increased discrepancies. The paired <i>t</i>-test showed a statistically significant difference betw","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12766702/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145900514","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}
Sara Mohammadi, Joshua Deslongchamps, Jiali Wang, Mary Ellen Jafari
<div> <section> <h3> Purpose</h3> <p>This study evaluates the effect of aluminum (Al) purity on Half Value Layer (HVL) measurements and beam quality across mobile and fixed radiographic units. Beam quality assessment is a fundamental aspect in ensuring the safe and effective delivery of ionizing radiation to patients. Standards for this assessment vary nationally and internationally, leading to ambiguity within measurements, which may cause regulatory compliance issues.</p> </section> <section> <h3> Methods</h3> <p>Beam filtration was measured using Al filters of 99.0% and 99.5% purity, for mobile and fixed radiographic units utilizing radiation detectors from three manufacturers. Methods and geometry followed IEC standards for HVL measurements with techniques representative of those used for standard patients. Measurements were made across a range of thicknesses of aluminum incrementally centered around the projected HVL. HVL was determined through exponential fitting of exposure versus Al thickness. Additionally, for each solid-state detector, a single-shot HVL measurement was performed without aluminum in the x-ray beam, as this method is commonly used for HVL determination in clinical settings.</p> </section> <section> <h3> Results</h3> <p>When Al filtration purity was increased from 99.0% to 99.5%, HVL measurements rose by 1.35% to 4.82%, with a median increase of 3.26% (95% confidence interval 2.68%–3.85%). The deviation between single-shot HVL measurements and interpolated values ranged from 0.16% to 8.99% (median: 4.90%; 95% CI: 3.32%–6.49%) for 99.0% purity Al, and from 0.43% to 4.79% (median: 2.62%; 95% CI: 1.60%–3.64%) for 99.5% purity Al.</p> </section> <section> <h3> Conclusion</h3> <p>There is a discrepancy in the purity of reference aluminum used for determining HVL specified in the United States Food and Drug Administration (FDA) and International Electrotechnical Commission (IEC) standards. FDA requires Type-1100 aluminum with a minimum of 99.0% purity, while IEC requires a minimum 99.9% purity. Our results indicate that measured HVL values increase with aluminum purity in a magnitude sufficient to result in units falsely failing regulatory requirements for minimum HVL if different types of aluminum are used by manufacturers and physicists. Medical physicists should be aware of this issue when testing HVL for compliance with regulatory standards. This study did not provide a direct comparison of FDA and IEC standards; instead, it demonstrates the direction and magnitude of HVL sensitivity to aluminum purity within clinically realis
{"title":"Beam quality assessment: Evaluating aluminum purity's effects","authors":"Sara Mohammadi, Joshua Deslongchamps, Jiali Wang, Mary Ellen Jafari","doi":"10.1002/acm2.70450","DOIUrl":"10.1002/acm2.70450","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>This study evaluates the effect of aluminum (Al) purity on Half Value Layer (HVL) measurements and beam quality across mobile and fixed radiographic units. Beam quality assessment is a fundamental aspect in ensuring the safe and effective delivery of ionizing radiation to patients. Standards for this assessment vary nationally and internationally, leading to ambiguity within measurements, which may cause regulatory compliance issues.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Beam filtration was measured using Al filters of 99.0% and 99.5% purity, for mobile and fixed radiographic units utilizing radiation detectors from three manufacturers. Methods and geometry followed IEC standards for HVL measurements with techniques representative of those used for standard patients. Measurements were made across a range of thicknesses of aluminum incrementally centered around the projected HVL. HVL was determined through exponential fitting of exposure versus Al thickness. Additionally, for each solid-state detector, a single-shot HVL measurement was performed without aluminum in the x-ray beam, as this method is commonly used for HVL determination in clinical settings.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>When Al filtration purity was increased from 99.0% to 99.5%, HVL measurements rose by 1.35% to 4.82%, with a median increase of 3.26% (95% confidence interval 2.68%–3.85%). The deviation between single-shot HVL measurements and interpolated values ranged from 0.16% to 8.99% (median: 4.90%; 95% CI: 3.32%–6.49%) for 99.0% purity Al, and from 0.43% to 4.79% (median: 2.62%; 95% CI: 1.60%–3.64%) for 99.5% purity Al.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>There is a discrepancy in the purity of reference aluminum used for determining HVL specified in the United States Food and Drug Administration (FDA) and International Electrotechnical Commission (IEC) standards. FDA requires Type-1100 aluminum with a minimum of 99.0% purity, while IEC requires a minimum 99.9% purity. Our results indicate that measured HVL values increase with aluminum purity in a magnitude sufficient to result in units falsely failing regulatory requirements for minimum HVL if different types of aluminum are used by manufacturers and physicists. Medical physicists should be aware of this issue when testing HVL for compliance with regulatory standards. This study did not provide a direct comparison of FDA and IEC standards; instead, it demonstrates the direction and magnitude of HVL sensitivity to aluminum purity within clinically realis","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12758990/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145892344","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}
Meriem Tantaoui, Mustapha Krim, Fatimzahra Chehab, El Mehdi Essaidi, Mohammed Reda Mesradi, Abdelkrim Kartouni, Souha Sahraoui
<div> <section> <h3> Background</h3> <p>In pediatric radiotherapy, controlling low-dose exposure is a major challenge, particularly in the treatment of medulloblastoma, where the long life expectancy of young patients makes optimization of radioprotection crucial.</p> </section> <section> <h3> Purpose</h3> <p>This study provides a comprehensive and quantitative assessment of low-dose exposure to normal tissues across the entire radiotherapy workflow, with a particular emphasis on the contribution of imaging procedures (planning computed tomography (CT) and repeated cone beam computed tomography (CBCT) acquisitions) in addition to therapeutic irradiation. The cumulative impact of these steps is evaluated together with the associated risks using Normal Tissue Complication Probability (NTCP) modeling.</p> </section> <section> <h3> Methods</h3> <p>A pediatric anthropomorphic phantom was equipped with optically stimulated luminescence (OSL) dosimeters to measure doses delivered to normal organs during the planning CT, 15 CBCT scans for positioning, and simulated treatment plans with different radiotherapy techniques. NTCPs were calculated for critical organs based on the dosimetric data from imaging and treatment planning.</p> </section> <section> <h3> Results</h3> <p>Each imaging acquisition delivered between 3 and 7 mGy per organ, with the cumulative dose from CT and CBCT remaining consistently below 0.5 Gy, representing less than 1% of the prescribed therapeutic dose. Although small compared to therapeutic irradiation, this contribution remains biologically relevant when considering cumulative low-dose exposure in pediatric patients. Dosimetric comparison of treatment techniques showed that volumetric modulated arc therapy (VMAT) significantly reduced both the mean organ dose and the NTCP compared to three-dimensional conformal radiation therapy (3D-CRT): heart dose decreased from 16 Gy (NTCP 30%) to 6.6 Gy (NTCP 0.4%), and thyroid dose from 27.1 Gy (NTCP 12%) to 8.7 Gy (NTCP < 1%). Some organs, such as the brain and chiasma, remained highly exposed, reflecting the dosimetric constraints of comprehensive tumor coverage.</p> </section> <section> <h3> Conclusion</h3> <p>By systematically quantifying and integrating imaging doses with therapeutic irradiation, this study underscores the often underestimated role of imaging in cumulative exposure during pediatric craniospinal irradiation. The results provide a solid foundation for tailoring radioprotec
{"title":"Organ-specific low-dose assessment in pediatric radiotherapy using nanodot OSL and NTCP modeling: Application to medulloblastoma","authors":"Meriem Tantaoui, Mustapha Krim, Fatimzahra Chehab, El Mehdi Essaidi, Mohammed Reda Mesradi, Abdelkrim Kartouni, Souha Sahraoui","doi":"10.1002/acm2.70444","DOIUrl":"10.1002/acm2.70444","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>In pediatric radiotherapy, controlling low-dose exposure is a major challenge, particularly in the treatment of medulloblastoma, where the long life expectancy of young patients makes optimization of radioprotection crucial.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>This study provides a comprehensive and quantitative assessment of low-dose exposure to normal tissues across the entire radiotherapy workflow, with a particular emphasis on the contribution of imaging procedures (planning computed tomography (CT) and repeated cone beam computed tomography (CBCT) acquisitions) in addition to therapeutic irradiation. The cumulative impact of these steps is evaluated together with the associated risks using Normal Tissue Complication Probability (NTCP) modeling.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>A pediatric anthropomorphic phantom was equipped with optically stimulated luminescence (OSL) dosimeters to measure doses delivered to normal organs during the planning CT, 15 CBCT scans for positioning, and simulated treatment plans with different radiotherapy techniques. NTCPs were calculated for critical organs based on the dosimetric data from imaging and treatment planning.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Each imaging acquisition delivered between 3 and 7 mGy per organ, with the cumulative dose from CT and CBCT remaining consistently below 0.5 Gy, representing less than 1% of the prescribed therapeutic dose. Although small compared to therapeutic irradiation, this contribution remains biologically relevant when considering cumulative low-dose exposure in pediatric patients. Dosimetric comparison of treatment techniques showed that volumetric modulated arc therapy (VMAT) significantly reduced both the mean organ dose and the NTCP compared to three-dimensional conformal radiation therapy (3D-CRT): heart dose decreased from 16 Gy (NTCP 30%) to 6.6 Gy (NTCP 0.4%), and thyroid dose from 27.1 Gy (NTCP 12%) to 8.7 Gy (NTCP < 1%). Some organs, such as the brain and chiasma, remained highly exposed, reflecting the dosimetric constraints of comprehensive tumor coverage.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>By systematically quantifying and integrating imaging doses with therapeutic irradiation, this study underscores the often underestimated role of imaging in cumulative exposure during pediatric craniospinal irradiation. The results provide a solid foundation for tailoring radioprotec","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12758999/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145892532","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}
In this study, a bias field correction workflow was proposed to improve the flexibility and generalizability of the generative adversarial network (GAN) model for abdominal cancer patients treated with a 0.35T magnetic resonance imaging linear accelerator (MR-LINAC) system.
Methods
Model training was performed using brain MR images acquired on a 3T diagnostic scanner, while model testing was performed using abdominal MR images obtained using a 0.35T MR-LINAC system. The performance of the proposed workflow was first compared with the GAN model using root-mean-square error (RMSE), peak signal-to-noise ratio (PSNR), and structural similarity index measure (SSIM). To assess the impact of the workflow on image segmentation, it was also compared with the N4ITK algorithm. Segmentation was performed using the k-means clustering algorithm with three clusters corresponding to air, fat, and soft tissue. Segmentation accuracy was then evaluated using the Dice similarity coefficient (DSC).
Results
The RMSE values were 30.59, 12.06, 10.37 for the bias field-corrupted images (IIN), GAN-corrected images (IGAN), and images corrected with the proposed workflow (IOUT), respectively. Corresponding PSNR values were 42.34, 46.04, 47.04 dB, and SSIM values were 0.84, 0.96, 0.98. For segmentation accuracy, the mean DSC for air masks was 0.95, 0.97, and 0.97; for fat masks, 0.61, 0.71, and 0.74; and for soft tissue masks, 0.60, 0.68, and 0.69, corresponding to IIN, N4ITK-corrected images (IN4ITK), and IOUT, respectively
Conclusion
By effectively mitigating bias field artifacts, the proposed workflow has the potential to strengthen the clinical utility of MRI-guided adaptive radiotherapy for abdominal cancers, ensuring safer and more accurate radiation delivery.
{"title":"A bias field correction workflow based on generative adversarial network for abdominal cancers treated with 0.35T MR-LINAC","authors":"Ching-Ching Yang, Hung-Te Yang","doi":"10.1002/acm2.70448","DOIUrl":"10.1002/acm2.70448","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>In this study, a bias field correction workflow was proposed to improve the flexibility and generalizability of the generative adversarial network (GAN) model for abdominal cancer patients treated with a 0.35T magnetic resonance imaging linear accelerator (MR-LINAC) system.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Model training was performed using brain MR images acquired on a 3T diagnostic scanner, while model testing was performed using abdominal MR images obtained using a 0.35T MR-LINAC system. The performance of the proposed workflow was first compared with the GAN model using root-mean-square error (RMSE), peak signal-to-noise ratio (PSNR), and structural similarity index measure (SSIM). To assess the impact of the workflow on image segmentation, it was also compared with the N4ITK algorithm. Segmentation was performed using the k-means clustering algorithm with three clusters corresponding to air, fat, and soft tissue. Segmentation accuracy was then evaluated using the Dice similarity coefficient (DSC).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The RMSE values were 30.59, 12.06, 10.37 for the bias field-corrupted images (I<sub>IN</sub>), GAN-corrected images (I<sub>GAN</sub>), and images corrected with the proposed workflow (I<sub>OUT</sub>), respectively. Corresponding PSNR values were 42.34, 46.04, 47.04 dB, and SSIM values were 0.84, 0.96, 0.98. For segmentation accuracy, the mean DSC for air masks was 0.95, 0.97, and 0.97; for fat masks, 0.61, 0.71, and 0.74; and for soft tissue masks, 0.60, 0.68, and 0.69, corresponding to I<sub>IN</sub>, N4ITK-corrected images (I<sub>N4ITK</sub>), and I<sub>OUT</sub>, respectively</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>By effectively mitigating bias field artifacts, the proposed workflow has the potential to strengthen the clinical utility of MRI-guided adaptive radiotherapy for abdominal cancers, ensuring safer and more accurate radiation delivery.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://aapm.onlinelibrary.wiley.com/doi/epdf/10.1002/acm2.70448","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145892389","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}
Michalis Aristophanous, Sernger Shen, Dylan G. Hsu, Dongxu Wang, Ase Ballangrud, Jean M. Moran, Anyi Li, Sean M. McBride, Daniel Gomez, Luke R. G. Pike, Kathryn Beal, Jonathan T. Yang, Laura Cervino
Purpose
We report our experience with the implementation of a same-day simulation and treatment C-arm linear accelerator (linac)-based stereotactic program for patients with intracranial and extracranial metastatic disease.
Methods
Between May 2021 and October 2023, patients were treated in our same-day program with linac-based SRS/SBRT. Two slots per week were offered. Patients with expedited clinical needs, able to undergo SRS/SBRT simulation and treatment, were considered. Extracranial treatments were required to meet standards for automated intensity modulated radiation therapy (IMRT) optimization. Intracranial treatments were limited to 1–3 lesions and 1–2 isocenters. The day before treatment, the patient needed to be identified, and any diagnostic imaging had to be available for the physician and dosimetrist to discuss the plan. On the day of treatment, simulation was scheduled for 8 AM and treatment at 4 PM by default, with the goal to complete treatment by 6 PM. We analyzed information about each patient's treatment plan and time spent on each step of the workflow.
Results
Ninety-seven patients followed our same-day workflow and were included in the analysis. Seventy-five patients received intracranial SRS (57% to 1 lesion), while 22 patients received extracranial treatments (50% to the extremities). Simulation often required additional time to be completed, finishing a median 18 min (IQR 5–40) after the goal end time. The median time between simulation completion and end of the same-day treatment was 7.8 h (IQR 7.4–8.6). Treatment technique and the number of target volumes had a significant impact on planning time. The median treatment end time was 5:13 PM (IQR 4:46 PM–6:01 PM), with 74% ending by 6 PM.
Conclusions
A linac-based program to treat patients with SRS/SBRT in an expedited fashion was established and successfully treated patients in a same-day timeline. Careful selection of planning techniques to limit plan complexity and adding automation in time-consuming parts of the process are crucial when developing expedited workflows.
{"title":"Clinical experience with a same-day simulation and treatment program for stereotactic radiation therapy on a C-arm linac","authors":"Michalis Aristophanous, Sernger Shen, Dylan G. Hsu, Dongxu Wang, Ase Ballangrud, Jean M. Moran, Anyi Li, Sean M. McBride, Daniel Gomez, Luke R. G. Pike, Kathryn Beal, Jonathan T. Yang, Laura Cervino","doi":"10.1002/acm2.70449","DOIUrl":"10.1002/acm2.70449","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>We report our experience with the implementation of a same-day simulation and treatment C-arm linear accelerator (linac)-based stereotactic program for patients with intracranial and extracranial metastatic disease.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Between May 2021 and October 2023, patients were treated in our same-day program with linac-based SRS/SBRT. Two slots per week were offered. Patients with expedited clinical needs, able to undergo SRS/SBRT simulation and treatment, were considered. Extracranial treatments were required to meet standards for automated intensity modulated radiation therapy (IMRT) optimization. Intracranial treatments were limited to 1–3 lesions and 1–2 isocenters. The day before treatment, the patient needed to be identified, and any diagnostic imaging had to be available for the physician and dosimetrist to discuss the plan. On the day of treatment, simulation was scheduled for 8 AM and treatment at 4 PM by default, with the goal to complete treatment by 6 PM. We analyzed information about each patient's treatment plan and time spent on each step of the workflow.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Ninety-seven patients followed our same-day workflow and were included in the analysis. Seventy-five patients received intracranial SRS (57% to 1 lesion), while 22 patients received extracranial treatments (50% to the extremities). Simulation often required additional time to be completed, finishing a median 18 min (IQR 5–40) after the goal end time. The median time between simulation completion and end of the same-day treatment was 7.8 h (IQR 7.4–8.6). Treatment technique and the number of target volumes had a significant impact on planning time. The median treatment end time was 5:13 PM (IQR 4:46 PM–6:01 PM), with 74% ending by 6 PM.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>A linac-based program to treat patients with SRS/SBRT in an expedited fashion was established and successfully treated patients in a same-day timeline. Careful selection of planning techniques to limit plan complexity and adding automation in time-consuming parts of the process are crucial when developing expedited workflows.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12758992/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145892485","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}
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