Journal of Applied Clinical Medical Physics最新文献

{"title":"Potential of isotoxic dose escalation with robustly optimized VMAT and IMPT for large hepatocellular carcinoma according to baseline liver function","authors":"Elise Cherek, Mark Ka Heng Chan, Diane Schott","doi":"10.1002/acm2.70846","DOIUrl":"10.1002/acm2.70846","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Large hepatocellular carcinoma (HCC) adjacent to gastrointestinal (GI) organs presents a constrained radiotherapy problem because dose escalation is limited by both hepatic reserve and serial-organ tolerance. Although intensity-modulated proton therapy (IMPT) can reduce uninvolved liver irradiation, its achievable advantage over volumetric modulated arc therapy (VMAT) may depend on baseline liver function and robustness to treatment uncertainties.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>To present and demonstrate a robust isotoxic dose-escalation framework for evaluating IMPT and VMAT in large HCC adjacent to GI organs while accounting for baseline liver function and treatment uncertainty.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Thirteen patients with HCC (equivalent tumor diameter, 3.0–20.9 cm) underwent comparative IMPT and VMAT treatment planning. Robust optimization incorporated 5-mm setup uncertainty for both modalities and 3% range uncertainty for IMPT. Dose escalation was performed using a fixed dose per fraction of 3.87 Gy while varying the maximum acceptable number of fractions, <i>N</i><sub>max</sub>, under non-cirrhotic, Child-Pugh A (CP-A), and Child-Pugh B (CP-B) liver-function assumptions. Liver mean dose constraints were evaluated on nominal dose, while serial-organ constraints were assessed using both nominal dose and voxel-wise maximum dose across uncertainty scenarios. Unirradiated liver volume normalized to standard liver volume (ULV/SLV) was used to estimate the relative hazard of radiation-induced liver disease (RILD).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>In the nominal-dose analysis, IMPT achieved a higher <i>N</i><sub>max</sub> than VMAT in 5 of 13, 8 of 13, and 8 of 13 patients under non-cirrhotic, CP-A, and CP-B assumptions, respectively, with mean Δ<i>N</i><sub>max</sub> values of 0.38, 1.23, and 1.69 fractions. Similar trends were observed in the voxel-wise maximum-dose analysis, where mean Δ<i>N</i><sub>max</sub> values were 0.00, 1.08, and 1.77 fractions, respectively. VMAT dose escalation was predominantly limited by mean liver dose, whereas IMPT was more frequently constrained by GI maximum-dose limits, indicating a shift from liver reserve to serial-organ tolerance as the primary limiting factor. Among patients with an IMPT dose-escalation advantage, IMPT maintained higher ULV/SLV and correspondingly lower estimated RILD hazard despite treatment escalation.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> ","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2026-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13643040/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149109887","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 DWWSS report 449: Evaluation of imaging physics workforce, workload, and future needs in the United States","authors":"Joseph R. Steiner,&nbsp;Shengwen Deng,&nbsp;Ching-Mei Feng,&nbsp;Joshua M. Wilson,&nbsp;Mary Ellen Jafari,&nbsp;Megan E. Lipford,&nbsp;Lei Qin,&nbsp;Dustin Gress,&nbsp;David Jordan","doi":"10.1002/acm2.70843","DOIUrl":"10.1002/acm2.70843","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Introduction</h3>\u0000 \u0000 <p>In 2020, the American Association of Physicists in Medicine (AAPM) conducted a comprehensive imaging physics workforce survey (2020 Survey) to evaluate staffing needs, validate prior time and effort estimates, and explore workforce satisfaction. This report summarizes key findings, highlighting gaps between training and professional demands, challenges in recruitment, and shifts in workforce demographics and employment patterns.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>The 2020 Survey, administered by the American Institute of Physics (AIP) Statistical Research Center (SRC) to AAPM and Health Physics Society members, had 953 responses from participants who were primarily diagnostic and nuclear medical physicists. The data were analyzed across four key areas: professional task workloads, workforce demographics and retirement outlook, lifestyle factors, and skill gaps.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results and Discussion</h3>\u0000 \u0000 <p>The AIP SRC analyzed the results of the 2020 Survey (results archived on the AAPM members-only website). The 2020 Survey validated the relative time required for equipment performance evaluations and the wide range of Level 2 services performed by the imaging physics workforce relative to AAPM Report 301. The 2020 Survey showed that the imaging physics workforce is aging (30% of respondents providing their age stated they were 66 years or older) and that many of these individuals could retire within 5 years of completing the survey. Finally, the 2020 Survey demonstrated that there were gaps between the skills and knowledge employers look for when hiring compared to the same self-identified qualities of the imaging physics workforce.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The 2020 Survey provided insights into the imaging physics workforce that validated prior publications estimating imaging physics workforce activities. The 2020 Survey indicates the imaging physics workforce is aging, with a wave of retirements on the horizon, and that individuals entering the workforce may not possess the skills and knowledge desired by employers. The data from this survey can be used to guide analyses and address future trends of the imaging physics field and workforce.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2026-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13643047/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149110057","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":"Assessment of image quality and detectability in computed tomography: Inter-laboratory comparison of Fourier-based metrics","authors":"Pascal Monnin,&nbsp;Damien Racine,&nbsp;Luis Ammour,&nbsp;Yves Barbotteau,&nbsp;Davide Cester,&nbsp;Dimitar Petrov,&nbsp;Kwinten Torfs,&nbsp;Raffaele Villa,&nbsp;Nicoletta Paruccini,&nbsp;Joël Greffier,&nbsp;Anaïs Viry","doi":"10.1002/acm2.70838","DOIUrl":"10.1002/acm2.70838","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Background&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;The task-based assessment of image quality in computed tomography (CT) is increasingly used for benchmarking, optimizing acquisition and reconstruction parameters, and predicting observers’ performance. To achieve consistent and reproducible results rely on standardized methodologies and guidelines.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Purpose&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;This study performed an inter-laboratory comparison to evaluate the consistency of CT image quality metrics and assess inter-laboratory variability.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Methods&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Six series of images of a Catphan 500 phantom were acquired at three dose levels (1.5/5.0/15.0 mGy) with two (standard and high-resolution) kernels and sent to seven independent laboratories. Participants calculated the task transfer function (TTF) for spatial resolution and noise power spectrum (NPS) for noise magnitude and texture using standardized Fourier-based analysis on the shared images. The TTFs and NPS were used in the non-prewhitening observer model without (NPW) and with eye filter (NPWE) to calculate a detectability index for small (2 mm) and large targets (10 mm).&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Results&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;The difference observed in TTFs resulted mainly from the different noise reduction techniques used during the calculation. The frequency corresponding to the TTF value 50% varied from 0.27 to 0.43 mm&lt;sup&gt;−1&lt;/sup&gt; for the standard images and from 0.73 to 0.92 mm&lt;sup&gt;−1&lt;/sup&gt; for the high-resolution images. Variability in NPS primarily stemmed from the choice of regions of interest location in non-stationary noise images that lead to magnitude differences up to 40% for the standard kernel and 70% for the high-resolution kernel. The combined differences in TTF and NPS resulted in differences up to 39% in the NPW detectability index. The large variability in the human visual transfer function and visualization parameters increased the differences by a factor of 6.25 in the NPWE model and highlighted the lack of standardization.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Conclusion&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Adapting TTF and NPS to a more complex and localized analysis of CT images with non-uniform CNRs, rather than a simple global evaluation, increases computational variability and requires a move towards more standardization of metrics. In the absence of complete standardization of image quality measurement, documentation of methods and all calculation parameters is essential for more robust e","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2026-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13641360/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149109816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of registration accuracy using short-arc cone-beam computed tomography for image-guided radiotherapy in breast cancer","authors":"Shuhei Wada,&nbsp;Masahide Tominaga,&nbsp;Motoharu Sasaki,&nbsp;Koichi Yamanashi,&nbsp;Yoshio Iwai,&nbsp;Shunsuke Furutani,&nbsp;Yusei Shinohara,&nbsp;Yoshihiro Uto","doi":"10.1002/acm2.70804","DOIUrl":"10.1002/acm2.70804","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Image-guided radiotherapy (IGRT) using cone-beam computed tomography (CBCT) enables highly accurate imaging registration; however, increased radiation exposure remains a concern. Recently, short-arc CBCT (SA-CBCT), which reduces projection data and reconstructs images, has become available. Although previous studies have shown that image quality deteriorates when projection data are reduced, no study has directly evaluated the clinical usefulness of SA-CBCT or its effect on registration accuracy.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>We verified the registration accuracy of SA-CBCT in breast tangential irradiation using an anthropomorphic phantom and clinical data, and examined its clinical feasibility compared with the commonly used 200° scan.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>An anthropomorphic phantom was placed on the treatment bed, and CT and CBCT images acquired during treatment planning were aligned. Bed movement was measured for both conventional CBCT and SA-CBCT images. The difference between the two measurements was quantified as <i>N</i>, defined as the norm of the vector difference between CBCT and SA-CBCT registration shifts, to evaluate registration accuracy. The acquisition angle was varied to assess the effects of central and total angles. In the clinical study, registration data from 30 consecutive patients who underwent whole-breast irradiation were analyzed. Data were reconstructed by changing the acquisition angle from 200° to 120°, and <i>N</i> was calculated as in the phantom experiment.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>In the phantom experiment, <i>N</i> was within 0.15 mm (3-axis) and 0.55 mm (6-axis) when the acquisition angle was reduced to 120°. In clinical data, the average <i>N</i> was 0.64 mm in 3-axis registration (84.7% within 1 mm) and 0.85 mm in 6-axis registration (71.3% within 1 mm). Even with a 120° acquisition angle, the body contour and chest wall edges were sufficiently preserved.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>SA-CBCT maintained adequate registration accuracy in breast tangential irradiation. These findings suggest its clinical applicability with appropriate acquisition angle settings.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2026-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13643054/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149109884","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":"Introducing a novel prediction index for treatment quality of gamma knife and stereotactic-based radiotherapy: Nabaa Efficiency Index (\u0000 \u0000 \u0000 η\u0000 Nabaa\u0000 \u0000 $eta^{{mathrm{Nabaa}}}$\u0000 )","authors":"Nabaa Mohammed Alsiraj,&nbsp;Haydar Hamza Alabedi,&nbsp;Mustafa Salih Almusawi,&nbsp;Moneer K. Faraj,&nbsp;Rozilawati Ahmad,&nbsp;Sura Abdulkareem Madlool Alzuabidi","doi":"10.1002/acm2.70805","DOIUrl":"10.1002/acm2.70805","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Background&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;An accurate assessment of the radiotherapy plans requires an accurate dose to the target and efficient confinement of the doses. However, present indices do not completely cover these aspects in a single framework.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Purpose&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;To develop a unified, dimensionless metric that integrates geometric conformity and dosimetric efficiency for evaluating stereotactic and fractionated radiotherapy plans aims to reduce QA workload by providing a rapid, quantitative estimate of plan acceptability, allowing early prediction of treatment plan performance.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Methods&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;In this study, the Nabaa Efficiency Index &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;msup&gt;\u0000 &lt;mi&gt;η&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;N&lt;/mi&gt;\u0000 &lt;mi&gt;a&lt;/mi&gt;\u0000 &lt;mi&gt;b&lt;/mi&gt;\u0000 &lt;mi&gt;a&lt;/mi&gt;\u0000 &lt;mi&gt;a&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msup&gt;\u0000 &lt;annotation&gt;$eta^{Nabaa}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; is introduced and defined as the product of the Conformity Index (CI) and a Dose-Efficiency Ratio (DER), evaluated at 50% and 90% isodose levels (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;msubsup&gt;\u0000 &lt;mi&gt;η&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mn&gt;50&lt;/mn&gt;\u0000 &lt;mo&gt;%&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;N&lt;/mi&gt;\u0000 &lt;mi&gt;a&lt;/mi&gt;\u0000 &lt;mi&gt;b&lt;/mi&gt;\u0000 &lt;mi&gt;a&lt;/mi&gt;\u0000 &lt;mi&gt;a&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msubsup&gt;\u0000 &lt;annotation&gt;$eta _{50% }^{Nabaa}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;msubsup&gt;\u0000 &lt;mi&gt;η&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mn&gt;90&lt;/mn&gt;\u0000 &lt;mo&gt;%&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;N&lt;/mi&gt;\u0000 &lt;mi&gt;a&lt;/mi&gt;\u0000 &lt;mi&gt;b&lt;/mi&gt;\u0000 &lt;mi&gt;a&lt;/mi&gt;\u0000 &lt;mi&gt;a&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msubsup&gt;\u0000 ","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2026-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13643063/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149110110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of testicular shielding effectiveness for surface and internal photon dose using a 3D-printed scrotal phantom","authors":"Joseph Speth,&nbsp;Josh Kilian-Meneghin,&nbsp;Salma K. Jabbour,&nbsp;Yin Zhang,&nbsp;Xiao Wang,&nbsp;Zhenyu Xiong,&nbsp;Ke Nie,&nbsp;Ning J. Yue,&nbsp;Xinxin Zhang","doi":"10.1002/acm2.70842","DOIUrl":"10.1002/acm2.70842","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Testicular shielding has long been used to reduce testicular dose during radiation treatment. However, quantitative evaluations of the effectiveness of such shielding in the literature vary substantially.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>In this study, the dose reduction expected at both the testicular skin surface and the inside of the testes was evaluated under different irradiation conditions, to enable informed clinical decision-making.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>A 3D printed scrotal phantom was designed to simulate patient testes and was composed of three layers to enable dose measurement inside the phantom. Gafchromic EBT3 film was used for dose measurements. The scrotal phantom was attached to a RANDO anthropomorphic phantom for computed tomography scanning and measurements. A commercial testicular shield with a lead wall thickness of 1.27 cm and a diameter of 6 cm was used for shielded measurements. The measured absolute dose was normalized to the delivered MU for each measurement to obtain a dose-to-MU value (cGy/MU). Both dose-to-MU values and shielding effectiveness were evaluated with a stationary anterior-posterior beam at different distances from field edge to scrotal phantom. In addition, the energy dependence of shielding effectiveness was assessed using two volumetric modulated arc therapy (VMAT) plans with identical parameters and modulation but using 6 and 15 MV energies.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The shielded and unshielded dose-to-MU values generally decreased with increasing field-to-phantom distance for both surface and internal dose measurements. However, the shielding ratio remained relatively constant across distances, with a reduction factor of approximately 3.3 for surface dose and 2.7 for internal dose. Minimal energy dependence was observed in both internal and surface dose measurements, as well as in shielding effectiveness, across the two VMAT plans. The overall shielding ratio was approximately 2.3 for both plans.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Testicular shielding reduced both surface and internal testicular dose by approximately a factor of 2 to 3, demonstrating consistent effectiveness across different irradiation geometries and photon energies.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13639242/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149109895","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":"Characterization of animal tissues for Monte Carlo simulations in ion beam therapy","authors":"Liu Xiaoli,&nbsp;Michael F. Moyers","doi":"10.1002/acm2.70836","DOIUrl":"10.1002/acm2.70836","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>To obtain better elemental compositions (ECs), physical densities (PDs), and relative linear stopping powers (RLSPs) of tissues scanned by single or dual energy computed tomography for use by Monte Carlo (MC) simulations of light ion beam therapy.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods and materials</h3>\u0000 \u0000 <p>The RLSPs of 12 animal tissue samples were measured using several different energy proton and carbon ion beams. The EC of each sample was analyzed using the following modern laboratory techniques: Inductively coupled plasma optical emission spectrometry (ICP-OES), inductively coupled plasma mass spectrometry (ICP-MS), organic elemental analysis (OEA), and ion chromatography (IC). RLSPs were calculated from both measured ECs and literature ECs and then compared with measured RLSPs. All samples underwent single-energy CT (SECT) and dual-energy CT (DECT) scanning after which a dual-energy index (DEI) was derived. A mapping from computed tomography number (CTN) and DEI to PD was performed.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>For each tissue sample, the measured RLSPs showed no significant dependence on beam energy or ion species, with all values agreeing to within ± 1% except for lung (within ± 2%). RLSPs directly measured and those calculated using measured PDs and ECs agreed within ± 2% except for lung. Measured RLSPs were slightly closer to values from laboratory-determined ECs than to literature ECs.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>RLSP measurements were independent of beam energy and ion species. The main determinants of accurate CTN to RLSP conversion are the PDs and fractional hydrogen content of the tissues. The accuracy of PD and EC for input into Monte Carlo transport calculations can be improved by combining DEI and scaled CTN.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13639258/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149109889","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":"Institutional CT dose reduction: A retrospective evaluation of dose indices from 2015–2024","authors":"Jayse M Weaver,&nbsp;Afrouz Ataei,&nbsp;Nicole E Murphy,&nbsp;Daniel R L'Heureux,&nbsp;Mark P Supanich","doi":"10.1002/acm2.70823","DOIUrl":"10.1002/acm2.70823","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Growing attention to radiation risks and dose reduction in CT imaging creates opportunities to present and discuss institutional dose trends and contributing factors.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>To provide an evaluation of 10-year trends in CT dose indices (CTDI_vol and DLP) from a multi-site and multi-scanner institution, with the hypothesis that doses have continued to decrease since the last national assessment of medical imaging doses due to scientific and technological improvements.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Data from a radiation dose index management system (Radimetrics, Bayer) were used to analyze diagnostic CT examinations from January 2015 to December 2024, stratified by procedure. Dose indices for the ten most utilized procedures were evaluated over the 10-year period using multivariable linear regression, adjusted for patient weight and age, to estimate annual percent change in dose. Procedures were further stratified by scanner model with quarterly median dose indices for qualitative investigation of trends. To investigate the relationship between dose reductions and image quality, archived annual ACR phantom images were retrieved and evaluated using a semi-automated software (https://ctpro.net/home).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Over the 10-year period, 695,575 diagnostic CT examinations of 235,233 patients were performed on 18 unique scanners (nine models) from three manufacturers. Multivariable linear regression, adjusted for patient weight and age, showed significant decreases in dose indices over time for most high-usage procedures. Model-specific qualitative analyses suggest that acquisition of new scanners, technique changes, and reductions in multiphase imaging were temporally associated with the observed decreases in dose indices. Additionally, the detectability index of low-contrast ACR phantom objects increased on new scanner models despite lower CTDI_vol.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>A retrospective review of CT exams demonstrated decreasing CTDI_vol and DLP across multiple frequently performed procedures, coinciding with known technique and technological changes.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13639238/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149109868","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":"Improving deep-learning IMRT plan quality for lymphoma using deliverability-aware training","authors":"Denis Kutnár,&nbsp;Ivan Richter Vogelius,&nbsp;Hristo Atanasov Georgiev,&nbsp;Lena Specht,&nbsp;Jens Petersen","doi":"10.1002/acm2.70815","DOIUrl":"10.1002/acm2.70815","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Background&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Deep learning (DL) methods have shown strong performance in predicting dose distributions from patient anatomy and target structures; however, accurate dose prediction does not guarantee a deliverable plan after conversion into machine parameters and dose recalculation in the treatment planning system (TPS), motivating training objectives that explicitly couple prediction to deliverability. Lymphoma presents substantial clinical heterogeneity in target location, extent, and prescription/fractionation, so fast automated methods that produce deliverable plans are particularly valuable.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Purpose&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;To investigate whether a deliverability-aware training framework improves the end-to-end deliverability of DL-generated intensity-modulated radiotherapy (IMRT) plans for lymphoma.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Methods&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;A retrospective single-institution dataset of 619 plans (571 patients; 2009–2021) was used. Clinical volumetric modulated arc therapy (VMAT) plans were converted to standardized 15-field coplanar sliding-window IMRT reference plans in Eclipse using automated scripting. Two DL approaches were compared: a baseline dose-only objective model (DL-DO) and a multi-objective model (DL-MO) trained with dose supervision, fluence supervision, and a dose–fluence–dose cycle-consistency constraint implemented via fixed inverse and forward networks. Predicted fluence maps were imported into the TPS, leaf-sequenced, and recalculated with AcurosXB without further optimization; plan quality was evaluated on a held-out test set (&lt;i&gt;n&lt;/i&gt; = 61) using planning target volume (PTV) &lt;i&gt;D&lt;/i&gt;&lt;sub&gt;98&lt;/sub&gt;, &lt;i&gt;D&lt;/i&gt;&lt;sub&gt;2&lt;/sub&gt;, and &lt;i&gt;D&lt;/i&gt;&lt;sub&gt;max&lt;/sub&gt; with paired Wilcoxon testing and Holm correction.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Results&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;DL-MO produced significantly better machine-deliverable plans than DL-DO, improving coverage and reducing hotspots (median paired differences: +12.31 percentage points (pp) in &lt;i&gt;D&lt;/i&gt;&lt;sub&gt;98&lt;/sub&gt;, −3.43 pp in &lt;i&gt;D&lt;/i&gt;&lt;sub&gt;2&lt;/sub&gt;, and −3.18 pp in &lt;i&gt;D&lt;/i&gt;&lt;sub&gt;max&lt;/sub&gt;; Holm-corrected &lt;i&gt;p&lt;/i&gt; &lt; 0.0001 for all). Mean ± SD PTV metrics were &lt;i&gt;D&lt;/i&gt;&lt;sub&gt;98&lt;/sub&gt; = 90.10 ± 3.74% vs. 78.59 ± 5.92%, &lt;i&gt;D&lt;/i&gt;&lt;sub&gt;2&lt;/sub&gt; = 106.28 ± 1.13% vs. 109.65 ± 2.40%, and &lt;i&gt;D&lt;/i&gt;&lt;sub&gt;max&lt;/sub&gt; = 110.32 ± 2.20% vs. 113.27 ± 3.03% (DL-MO vs. DL-DO). DL-MO approached the TPS reference IMRT plans (&lt;i&gt;D&lt;/i&gt;&lt;sub&gt;98&lt;/sub&gt; = 91.62 ± 3.45%) with residual hotspot elevation.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 ","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13639240/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149109909","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 practical framework for routine verification of Spot Position Monitor coordinate consistency in scanned carbon-ion radiotherapy","authors":"Toshiro Tsubouchi,&nbsp;Noriaki Hamatani,&nbsp;Akira Komada,&nbsp;Masaaki Takashina","doi":"10.1002/acm2.70844","DOIUrl":"10.1002/acm2.70844","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Log file–based patient specific quality assurance (PSQA) in scanned particle therapy relies on the consistency of spot position information recorded by the spot position monitor (SPM), but practical methods for routine independent verification of these coordinates remain limited.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>This study describes a practical framework for routine verification of SPM coordinate consistency using independent scintillator-based measurements in raster-scanning carbon-ion radiotherapy.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Reference spot positions were measured at the isocenter plane using a scintillator-based detector. Corresponding SPM-recorded spot coordinates were extracted from delivery log files. The two coordinate sets were aligned using a similarity transformation accounting for translation, rotation, and isotropic scaling. Post-transformation root-mean-square (RMS) residuals were used as a practical consistency metric reflecting the agreement between SPM-reported and independently measured spot positions under routine QA conditions.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>After similarity transformation, the median RMS residual across all investigated accelerator energies and irradiation ports was 1.45 mm, with an interquartile range of 1.36–1.63 mm. No statistically significant difference was detected across accelerator energies, whereas a significant difference was observed among irradiation ports.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The proposed framework provides a practical approach for routine verification of SPM coordinate consistency and for establishing facility-specific baselines through longitudinal monitoring. The RMS residual should not be interpreted as the intrinsic positional error of the SPM alone, but to provide a framework for establishing a facility-specific baseline for monitoring the agreement between SPM-reported and independently measured spot coordinates under routine QA conditions.</p>\u0000 </section>\u0000 </div>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":"27 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13639247/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149110023","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}