Journal of Applied Clinical Medical Physics最新文献

{"title":"Simulation-free workflow for lattice radiation therapy using deep learning predicted synthetic computed tomography: A feasibility study.","authors":"Libing Zhu, Nathan Y Yu, Safia K Ahmed, Jonathan B Ashman, Diego Santos Toesca, Michael P Grams, Christopher L Deufel, Jingwei Duan, Quan Chen, Yi Rong","doi":"10.1002/acm2.70137","DOIUrl":"https://doi.org/10.1002/acm2.70137","url":null,"abstract":"<p><strong>Purpose: </strong>Lattice radiation therapy (LRT) is a form of spatially fractionated radiation therapy that allows increased total dose delivery aiming for improved treatment response without an increase in toxicities, commonly utilized for palliation of bulky tumors. The LRT treatment planning process is complex, while eligible patients often have an urgent need for expedited treatment start. In this study, we aimed to develop a simulation-free workflow for volumetric modulated arc therapy (VMAT)-based LRT planning via deep learning-predicted synthetic CT (sCT) to expedite treatment initiation.</p><p><strong>Methods: </strong>Two deep learning models were initially trained using 3D U-Net architecture to generate sCT from diagnostic CTs (dCT) of the thoracic and abdomen regions using a training dataset of 50 patients. The models were then tested on an independent dataset of 15 patients using image similarity analysis assessing mean absolute error (MAE) and structural similarity index measure (SSIM) as metrics. VMAT-based LRT plans were generated based on sCT and recalculated on the planning CT (pCT) for dosimetric accuracy comparison. Differences in dose volume histogram (DVH) metrics between pCT and sCT plans were assessed using the Wilcoxon signed-rank test.</p><p><strong>Results: </strong>The final sCT prediction model demonstrated high image similarity to pCT, with a MAE and SSIM of 38.93 ± 14.79 Hounsfield Units (HU) and 0.92 ± 0.05 for the thoracic region, and 73.60 ± 22.90 HU and 0.90 ± 0.03 for the abdominal region, respectively. There were no statistically significant differences between sCT and pCT plans in terms of organ-at-risk and target volume DVH parameters, including maximum dose (Dmax), mean dose (Dmean), dose delivered to 90% (D90%) and 50% (D50%) of target volume, except for minimum dose (Dmin) and (D10%).</p><p><strong>Conclusion: </strong>With demonstrated high image similarity and adequate dose agreement between sCT and pCT, our study is a proof-of-concept for using deep learning predicted sCT for a simulation-free treatment planning workflow for VMAT-based LRT.</p>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":" ","pages":"e70137"},"PeriodicalIF":2.0,"publicationDate":"2025-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144274948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Producing high quality cranial SRS plans with 4Pi planning technique in a commercial clinical solution.","authors":"Ganesh Narayanasamy, Nishan Shrestha, Milan Bimali, Fen Xia, Zhong Su","doi":"10.1002/acm2.70115","DOIUrl":"https://doi.org/10.1002/acm2.70115","url":null,"abstract":"<p><strong>Purpose: </strong>To generate high-quality stereotactic radiosurgery (SRS) plans for single cranial lesions using 4Pi planning technique and compare these to our clinical \"status quo\" plans.</p><p><strong>Methods: </strong>Eighteen vestibular schwannoma (VS) patients previously planned with Varian Eclipse RapidArc and treated on a Varian TrueBeam using 6FFF MV photon beams were randomly selected. This cohort was replanned in Brainlab Elements Cranial SRS using an automatic 4Pi trajectory optimization technique (\"Elements 4Pi\"). \"Elements ArcMatch\" plans were also created, which utilized the identical arc geometry as the clinical plans in Eclipse, that is, used identical table angles, gantry start and stop angles, and collimator angles to isolate the inherent differences between the two treatment planning systems. SRS plan evaluation metrics included the Inverse Paddick conformity index (IPCI), gradient index (GI), max doses to the brainstem and ipsilateral cochlea, and number of monitor units (MUs). Pairwise comparisons between Eclipse and Elements 4Pi plans were performed using Wilcoxon signed rank test. For three-way comparisons with Elements-ArcMatch plans, the difference in distribution of SRS metrics was assessed first based on Friedman's test, followed by pairwise comparison if the findings from Friedman's test met statistical significance. A two-sided p-value of 0.05 was used to determine statistical significance.</p><p><strong>Results: </strong>While both Elements 4Pi and Elements ArcMatch plans had significantly lower GI, MU, and max doses to the brainstem and ipsilateral cochlea compared to Eclipse plans (p-values < 0.05), Elements 4Pi also had significantly lower IPCI values.</p><p><strong>Conclusion: </strong>The automation in Brainlab Elements Cranial SRS outperformed manual expert planning and produced collision-free and clinically deliverable plans for single targets with significantly better dose conformality, dose gradient, and lower dose to normal organs while using lower MUs compared to clinically delivered Eclipse plans.</p>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":" ","pages":"e70115"},"PeriodicalIF":2.0,"publicationDate":"2025-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144274947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correction to: \"AAPM WGWMRSC Report 420: chapter climate check: Mixed methods analysis of survey responses\".","authors":"","doi":"10.1002/acm2.70131","DOIUrl":"https://doi.org/10.1002/acm2.70131","url":null,"abstract":"","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":" ","pages":"e70131"},"PeriodicalIF":2.0,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144266305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comprehensive end-to-end dosimetry audit for stereotactic body radiotherapy in spine, lung, and soft tissue.","authors":"Maddison Shaw, Andrew Alves, Jessica Lye, Joerg Lehmann, Fayz Kadeer, Sabeena Beveridge, Nicholas Hardcastle, Moshi Geso, Rhonda Brown","doi":"10.1002/acm2.70133","DOIUrl":"https://doi.org/10.1002/acm2.70133","url":null,"abstract":"<p><strong>Purpose: </strong>To create and conduct a comprehensive onsite end-to-end dosimetry audit to assess treatment accuracy of spine, lung, and soft tissue Stereotactic Body Radiotherapy (SBRT) across Australian and New Zealand (ANZ) radiotherapy centers.</p><p><strong>Methods: </strong>The Australian Clinical Dosimetry Service (ACDS) anthropomorphic thorax phantom underwent a CT scan, planning, and treatment delivery according to local techniques at 128 facilities. Target volumes and dose constraints for spine, lung, and soft tissue were defined by the ACDS. Each plan was measured using Gafchromic EBT3 film and PTW 60019 microDiamond detector. A total of 782 plans were measured on 159 treatment machines of various classes and vendors. Audit results with the measured dose calculated as dose-to-medium, in medium (D_m,m) or dose-to-scaled density water, in water (D_w,w) were reported for all measurements, including those made in bone and lung equivalent materials.</p><p><strong>Results: </strong>The overall audit pass rate was 96% (271/281 plans) for the soft tissue case, 90% (215/238) for the spine, and 90% (236/263) for the lung. The average gamma pass rate for 5%/2mm criteria was 98.7% (soft tissue), 96.5% (spine), and 96.5% (lung). The average point dose difference was -1.0% (± 2.3%), 0.1% (± 3.8%), and -0.3% (± 3.2%) for the soft tissue, spine, and lung cases, respectively. The most common failure modes were in-target dose differences (41.6%) and Image Guided Radiation Therapy (IGRT) mismatches (36.7%).</p><p><strong>Conclusions: </strong>High pass rates were seen for soft tissue, spine, and lung SBRT, indicating safe implementation of practice in the ANZ region. The modes of failure were assessed for suboptimal results, with the most frequent error due to IGRT mismatches, followed by dose differences in field, either underdosing or overdosing.</p>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":" ","pages":"e70133"},"PeriodicalIF":2.0,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144234191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The edge visualization metric: Quantifying the improvement of lung SBRT target definition with 4D CBCT.","authors":"Colton Baley, Sam Andersen, Clark Anderson, Shraddha Dalwadi, Daniel L Saenz","doi":"10.1002/acm2.70114","DOIUrl":"https://doi.org/10.1002/acm2.70114","url":null,"abstract":"<p><strong>Purpose: </strong>Four-dimensional cone-beam CT (4D CBCT) incorporates oversampling of 3D data to reconstruct multi-phase CBCT data sets representing distinct phases of the breathing cycle based on a diaphragmatic correlate of respiratory motion. Motion artifacts and blurring can be reduced relative to three-dimensional cone-beam (3D CBCT), allowing clinicians to better visualize motion of targets. To quantitatively understand the degree to which target visualization is improved by 4D CBCT, an edge visualization metric (EVM) has been developed to describe the change in voxel intensities at the edge of targets in 4D CBCT maximum intensity projection images relative to 3D CBCT images.</p><p><strong>Methods: </strong>The EVM describes the median distance where voxel intensities drop from 80% to 20% of target voxel values. The EVM was evaluated in a phantom study with a CIRS dynamic thorax phantom and with eleven on-treatment lung SBRT patients.</p><p><strong>Results: </strong>In the phantom study, the EVM was improved for 4D CBCT relative to 3D CBCT for one-cm targets (2.43 ± 0.22 mm vs. 2.67 ± 0.31 mm, p = 0.04) and for 2-cm targets (2.60 ± 0.35 mm vs. 3.46 ± 1.03 mm, p = 0.02). In patients, the EVM was 3.59 ± 1.01 mm vs. 4.25 ± 1.24 mm (p < 0.05).</p><p><strong>Conclusions: </strong>When evaluating an imaging acquisition's degree of motion blurring and ability to delineate target edges, EVM may provide a less biased way to evaluate edge detection in the presence of motion when compared to traditional methods.</p>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":" ","pages":"e70114"},"PeriodicalIF":2.0,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144234192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advantages and limitations of navigation-based multicriteria optimization (MCO) in selectively sparing pharyngeal constrictor muscles in head and neck radiotherapy treatment planning.","authors":"Laura K Howard, Simon J P Meara, Ehab M Ibrahim, Carl G Rowbottom","doi":"10.1002/acm2.70112","DOIUrl":"https://doi.org/10.1002/acm2.70112","url":null,"abstract":"<p><strong>Purpose: </strong>Sparing pharyngeal constrictor muscles (PCMs) during radiotherapy improves patient-reported swallowing function. This study aimed to explore the feasibility of integrating knowledge-based planning (KBP) with multicriteria optimization (MCO) in Eclipse v18.0 to selectively spare PCM, quantify the required trade-off in prophylactic planning target volume (PTV54) coverage, and to evaluate MCO performance.</p><p><strong>Method: </strong>Ten patients previously planned with KBP for oropharyngeal cancer (65, 60, and 54 Gy in 30 fractions) were retrospectively re-planned. Clinical plans were further optimized using trade-off exploration in MCO, with a priority order: spinal cord and brainstem sparing, high-dose and intermediate-dose target coverage, PCM sparing, low-dose target coverage, parotids sparing, remaining organs at risk (OAR). Plans were evaluated based on planning target volumes dose metrics (D_50%, D_98%, and D_2%), homogeneity index (HI), conformity index (CI), and maximum and mean doses to OARs, and paired t-tests were performed. Differences between navigated and deliverable plans were analyzed. One patient underwent 10 identical repeat plan generations.</p><p><strong>Results: </strong>MCO reduced the average mean dose to the superior and middle PCM, inferior PCM, contralateral parotid, and larynx by 2.0, 3.4, 2.6, and 3.9 Gy, respectively (p < 0.05) but at the expense of HI and CI. No difference was observed in average PTV54 D_98% between techniques; however, all clinical plans and seven MCO plans achieved D_98% ≥ 95%, with three MCO plans modestly compromised (D_98% 93.7%-94.6%). Dose metrics between navigated and deliverable plans differed by ≤0.7 Gy for mean doses and ≤1.8 Gy for maximum doses. Pareto surface generation was not repeatable.</p><p><strong>Conclusion: </strong>MCO effectively balances the trade-off between PCM sparing and low-dose target coverage. It may be a valuable tool in the context of personalized care.</p>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":" ","pages":"e70112"},"PeriodicalIF":2.0,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144225498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of respiratory motion on dose distribution in SIB-SBRT for lung cancer.","authors":"Lingling Liu, Zhenle Fei, Jie Li, Jiong Shu, Jingyuan Shao, Jianguang Zhang, Xiangli Cui, Hongzhi Wang","doi":"10.1002/acm2.70136","DOIUrl":"https://doi.org/10.1002/acm2.70136","url":null,"abstract":"<p><strong>Purpose: </strong>Respiratory motion is a major source of dose uncertainty in lung cancer radiotherapy. The dose distribution of simultaneous integrated boost-stereotactic body radiotherapy (SIB-SBRT) is inhomogeneous and is significantly impacted by respiratory motion for lung cancer. The effect of respiratory motion on SIB-SBRT was investigated with a four-dimensional (4D) dose calculation method.</p><p><strong>Methods: </strong>Nineteen previously treated lung cancer patients were selected for this planning study. All patients underwent four-dimensional CT (4D-CT) scanning, and volumetric modulated arc therapy (VMAT) treatments were planned with internal target volume (ITV) and planning target volume (PTV). Dose distributions (3D-plan) were calculated on the average reconstruction of the 4D-CT. 4D dose distributions (4D-plan) were calculated to evaluate respiratory motion effects. These calculations were performed on the CT images of related respiratory phase with a respiration-correlated assignment of the 3D plan's monitor units to the respiratory phases of the 4D-CT. Subsequently, the accumulative 4D dose based on deformable registrations of the CT series was generated and compared to the 3D dose distribution. Dosimetric deviations in targets and organs at risk (OARs) were analyzed with dosimetric parameters, and correlations between dose deviations (ΔV₁₀₀ (ITV, PTV)) and patient characteristics (left-right, SI, anterior-posterior, S, L, Volume (ITV, PTV)) were explored.</p><p><strong>Results: </strong>With deformable registrations, the median values of relative differences between 3D-plan and 4D-plan 0 were found to be from -6.6% to 12.1% for all targets dosimetric parameters, and from -4.2% to 1.4% for OAR parameters. It was also shown that PTV coverage dropped more significantly than that of ITV with respiratory motion. Strong correlations were observed between the ΔV₁₀₀ (ITV, PTV) and patient characteristic (SI, S, L).</p><p><strong>Conclusion: </strong>Respiratory motion effects during SIB-SBRT treatment resulted in non-negligible dose variability. Furthermore, with the correlation relationship and respiratory motion parameters, the dose coverage reduction of targets could be predicted.</p>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":" ","pages":"e70136"},"PeriodicalIF":2.0,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144215909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"UR-cycleGAN: Denoising full-body low-dose PET images using cycle-consistent Generative Adversarial Networks.","authors":"Yang Liu, ZhiWu Sun, HaoJia Liu","doi":"10.1002/acm2.70124","DOIUrl":"https://doi.org/10.1002/acm2.70124","url":null,"abstract":"<p><strong>Purpose: </strong>This study aims to develop a CycleGAN based denoising model to enhance the quality of low-dose PET (LDPET) images, making them as close as possible to standard-dose PET (SDPET) images.</p><p><strong>Methods: </strong>Using a Philips Vereos PET/CT system, whole-body PET images of fluorine-18 fluorodeoxyglucose (18F-FDG) were acquired from 37 patients to facilitate the development of the UR-CycleGAN model. In this model, low-dose data were simulated by reconstructing PET images with a 30-s acquisition time, while standard-dose data were reconstructed from a 2.5-min acquisition. The network was trained in a supervised manner on 13 210 pairs of PET images, and the quality of the images was objectively evaluated using peak signal-to-noise ratio (PSNR) and structural similarity index (SSIM).</p><p><strong>Results: </strong>Compared to simulated low-dose data, the denoised PET images generated by our model showed significant improvement, with a clear trend toward SDPET image quality.</p><p><strong>Conclusion: </strong>The proposed method reduces acquisition time by 80% compared to standard-dose imaging, while achieving image quality close to SDPET images. It also enhances visual detail fidelity, demonstrating the feasibility and practical utility of the model for significantly reducing imaging time while maintaining high image quality.</p>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":" ","pages":"e70124"},"PeriodicalIF":2.0,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144208556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Radiotherapy medical physics in the Philippines: A contemporary overview.","authors":"John Paul C Cabahug, Ramon Carlo Cruzpero, Luis E Fong de Los Santos, Eric C Ford, Afua A Yorke","doi":"10.1002/acm2.70129","DOIUrl":"https://doi.org/10.1002/acm2.70129","url":null,"abstract":"<p><strong>Purpose: </strong>With cancer ranking as the third leading cause of death in the Philippines and a disparity in healthcare resources across regions, this research aimed to assess the state of radiotherapy medical physics in the country.</p><p><strong>Methodology: </strong>The study utilized a comprehensive online survey with 94 structured questions answered by 19 clinics.</p><p><strong>Results: </strong>Most of the participants were within 1-3 years of training (41%), with a slight majority working in private hospitals (55%). linear accelerators (LINACs) were universally used with one Co-60 unit available, and High Dose Rate (HDR) brachytherapy was common. Intensity-Modulated Radiotherapy (IMRT) and 3D-Conformal Radiotherapy (3D-CRT) are practiced in all 19 clinics, with advanced techniques like Stereotactic Body Radiotherapy (SBRT), Stereotactic Radiosurgery (SRS), and Intraoperative Radiotherapy (IORT) limited to NCR, while modalities such as Volumetric Modulated Arc Therapy (VMAT) (21%) and 2D RT (68%) are more widely practiced. Imaging modalities included the wide adoption of Computed Tomography (CT), though only 64% of respondents had dedicated CT simulators in their clinics. Gynecologic and breast cancers were frequently treated, while bone marrow transplants (total body irradiation) were rare. For quality assurance (QA) devices, Solid Water Phantoms and Scanning Water Tanks (86%) were the most common devices for dosimetry and measurement. 82% reported performing patient-specific QA (PSQA), with EPID dosimetry being the most common (55%) PSQA device used. Quality management practices varied between Qualified Medical Physicists and Medical Physics Trainees, with most Qualified Medical Physicists performing routine checks. Treatment interruptions were mainly due to staffing and machine downtime, rather than power outages or natural disasters. Most clinics had their own systems (86%) to document safety incidents, but only a few reported incidents (32%) to the IAEA SAFRON program. Lastly, participants expressed a willingness to collaborate in research despite limited time.</p><p><strong>Conclusion: </strong>This study provides an understanding of the current landscape of radiation therapy physics in the Philippines, highlighting the need to address workforce disparities, ensure equitable cancer treatment access, optimize dosimetric tools and QA devices, and prioritize resource allocation and research collaboration to advance radiation oncology practices.</p>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":" ","pages":"e70129"},"PeriodicalIF":2.0,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144191854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Accuracy and reproducibility of a single-pose image-to-robot registration method for mobile C-arm cone beam CT guided histotripsy.","authors":"Grace M Minesinger, Paul F Laeseke, Katrina L Falk, Claire E Hennen, Michael A Speidel, Martin G Wagner","doi":"10.1002/acm2.70132","DOIUrl":"https://doi.org/10.1002/acm2.70132","url":null,"abstract":"<p><strong>Purpose: </strong>Histotripsy is a focal tumor therapy that utilizes focused ultrasound (US) to mechanically destroy tissue. To overcome visualization limitations of diagnostic US-guidance, C-arm cone beam CT (CBCT)-guided histotripsy is being developed, for which a mobile C-arm could increase accessibility. CBCT-guided histotripsy uses a phantom with a helical fiducial pattern to determine the CBCT-to-histotripsy robot coordinate transformation. This study presents an image-to-robot registration method requiring only one phantom CBCT, evaluated for accuracy and reproducibility using a mobile C-arm.</p><p><strong>Methods: </strong>The phantom is attached to a robotic arm (replacing the histotripsy transducer) and positioned at isocenter. A CBCT is acquired and image-to-robot registration performed by registering a digital model of the phantom to observed fiducials in CBCT coordinates. Registration was performed by one user (n = 8/day, 2 days) and by 12 different users (n = 4/day, 3 days) with fiducial registration errors (FREs) calculated. After each registration, the transducer was reattached to the robot and a treatment delivered in a multi-layered, agar-based phantom. Directional and target registration errors (TREs) were calculated as directional and Euclidean distances between planned and observed treatments. Directional error inter-day differences for the single-user experiment were evaluated for significance using 2-tailed unpaired Student t-tests. The effect of user variability on variability of FRE and directional error was evaluated for significance using 2-tailed F-tests.</p><p><strong>Results: </strong>Registrations yielded FRE of 0.12 ± 0.03 mm and TRE of 1.51 ± 0.83 mm. Targeting error significantly increased along the transducer's short axis between days (0.88 ± 0.60 vs 1.43 ± 0.18 mm, p = 0.025) for the single user, with a similar trend for the multi-user experiment (1.45 ± 0.79, 2.70 ± 0.19, and 2.83 ± 0.40 mm). User variability, and thus robot pose variability, did not significantly affect variability of FRE or directional error.</p><p><strong>Conclusions: </strong>Mobile C-arm CBCT-guided histotripsy showed high accuracy with minimal yet nonnegligible TREs, consistent within but not between days, demonstrating that errors can be measured and accounted for, ideally near treatment day to maximize accuracy.</p>","PeriodicalId":14989,"journal":{"name":"Journal of Applied Clinical Medical Physics","volume":" ","pages":"e70132"},"PeriodicalIF":2.0,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144225497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}