Physics in medicine and biology最新文献

{"title":"Bragg-peak FLASH Biological Optimization Enables Enhanced Normal Tissue Sparing and Dose Escalation for Ocular Stereotactic Body Radiation Therapy.","authors":"Muhammad Hamza, Balaji Selvaraj, Xingyi Zhao, Chingyun Cheng, Tyler Kaulfers, Grant Lattery, Huifang Zhai, Charles Simone, Christopher Barker, Jenghwa Chang, Haibo Lin, Minglei Kang","doi":"10.1088/1361-6560/ae0ef7","DOIUrl":"https://doi.org/10.1088/1361-6560/ae0ef7","url":null,"abstract":"<p><strong>Objective: </strong>To evaluate proton Bragg peak FLASH for ocular treatments to enhance normal tissue sparing and enable dose escalation via FLASH biological optimization(FBO).&#xD;Approach: The FLASH-sparing factors for normal tissues were derived from the literature in modeling the phenomenological FLASH normal tissue sparing effect. Using the single-energy BP-FLASH technique(SEBP-FLASH), an in-house treatment planning system was implemented with the FLASH FBO module. Ten consecutive ocular patients who were treated using conventional dose rate intensity-modulated proton therapy(CONV-IMPT) to 50Gy in 5 fractions were replanned using the FLASH technique. The dose metrics for the OARs were compared using the two different techniques. The fraction dose was then intentionally escalated from 10 to 12Gy through FBO to assess whether the plans still met clinical constraints. &#xD;Main results: In the FLASH regimen without FBO(50Gy/5 fractions), all ipsilateral OAR dosimetric metrics met clinical objectives with safe margins. While the clinical CONV-IMPT approach demonstrated slightly better dosimetric performance than SEBP-FLASH plans, the incorporation of FBO improved all OAR dose metrics beyond those of CONV- IMPT, except for the mean dose to the cornea (no difference). When the target dose was increased from 50 to 60Gy using FBO, all OARs remained within clinical limits. The mean and maximum doses to the cornea increased from 11.7 to 15.4Gy and from 22.8 to 23.6Gy, respectively, when transitioning from 50Gy CONV- IMPT to 60Gy FBO. However, in the 60Gy FBO plans, the maximum doses were reduced for the eye (102.0% to 87.0%), optic nerves (98.7% to 74.0%), retina (100.5% to 81.8%), lacrimal gland (84.9% to 73.2%), and conjunctiva (91% to 72.3%).&#xD;Significance: SEBP-FLASH achieves plan quality comparable to CONV-IMPT using 50 Gy/5 fractions and enables dose escalation via FLASH FBO while meeting clinical standards, potentially improving tumor control with acceptable toxicity.</p>","PeriodicalId":20185,"journal":{"name":"Physics in medicine and biology","volume":" ","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145213467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Inter-slice Complementarity Enhanced Ring Artifact Removal using Central Region Reinforced Neural Network.","authors":"Yikun Zhang, Guannan Liu, Zhanghao Chen, Zujian Huang, Shengqi Kan, Xu Ji, Shouhua Luo, Shouping Zhu, Jian Yang, Yang Chen","doi":"10.1088/1361-6560/ae0deb","DOIUrl":"https://doi.org/10.1088/1361-6560/ae0deb","url":null,"abstract":"<p><p>In computed tomography (CT), non-uniform detector responses often lead to ring artifacts in reconstructed images. For conventional energy-integrating detectors (EIDs), such artifacts can be effectively addressed through dead-pixel correction and flat-dark field calibration. However, the response characteristics of photon-counting detectors (PCDs) are more complex, and standard calibration procedures can only partially mitigate ring artifacts. Consequently, developing high-performance ring artifact removal algorithms is essential for PCD-based CT systems. To this end, we propose the Inter-slice Complementarity Enhanced Ring Artifact Removal (ICE-RAR) algorithm. Since artifact removal in the central region is particularly challenging, ICE-RAR utilizes a dual-branch neural network that could simultaneously perform global artifact removal and enhance the central region restoration. Moreover, recognizing that the detector response is also non-uniform in the vertical direction, ICE-RAR suggests extracting and utilizing inter-slice complementarity to enhance its performance in artifact elimination and image restoration. Experiments on simulated data and two real datasets acquired from PCD-based CT systems demonstrate the effectiveness of ICE-RAR in reducing ring artifacts while preserving structural details. More importantly, since the system-specific characteristics are incorporated into the data simulation process, models trained on the simulated data can be directly applied to unseen real data from the target PCD-based CT system, demonstrating ICE-RAR's potential to address the ring artifact removal problem in practical CT systems. The implementation is publicly available at https://github.com/DarkBreakerZero/ICE-RAR.</p>","PeriodicalId":20185,"journal":{"name":"Physics in medicine and biology","volume":" ","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145200685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimizing the ferumoxytol dose for vascular suppression in brachial plexus magnetic resonance neurography.","authors":"Allison S Lowe, Darryl B Sneag, Shayna E Turbin, Mylinh Duong, Shu-Han Wang, Daniel M Alschuler, Ek T Tan","doi":"10.1088/1361-6560/ae0864","DOIUrl":"10.1088/1361-6560/ae0864","url":null,"abstract":"<p><p><i>Background.</i>Magnetic resonance neurography (MRN) enables visualization of peripheral nerves using T2-weighted, fat-suppressed sequences. However, vascular signal contamination in the brachial plexus remains a challenge. Ferumoxytol, an ultra-small paramagnetic iron oxide agent, can suppress vascular signal in MRN due to its high T2 relaxivity and longer half-life, but the optimal dose is unknown.<i>Objective.</i>To evaluate whether a subject-specific dose of Ferumoxytol, based on weight and estimated blood volume, improves vascular suppression in brachial plexus MRN, as compared to using a fixed-dose.<i>Approach.</i>Thirty-four healthy adult subjects (16 female, age = 25.0 ± 2.2 years, mean [range] weight = 66.90 [44.00, 97.52] kg) underwent slow Ferumoxytol infusion (<36 mg Fe min^-1) followed by unilateral brachial plexus MRN at 3.0T. Subjects were divided into three cohorts: variable dose (6%-26% of full 510 mg dose), fixed 25% dose (Cohort 2), and fixed 50% dose (Cohort 3). Signal intensities of nerve, artery, vein, and muscle were obtained via manual segmentation. Contrast ratios (CR) between vessel-muscle and nerve-muscle were compared between cohorts using two-sample<i>t</i>-tests. Regression analysis was performed between vessel-muscle CR and the Ferumoxytol dose calculated by mg, mg kg^-1, and mg l^-1. The doses required to achieve a target vessel-muscle CR of 0.2 were calculated.<i>Main results.</i>Cohort 3 had superior vascular suppression compared to Cohort 1 (i.e. lower vessel-muscle CR,<i>p</i>< 0.05). Higher correlations of vein-muscle CR with subject-specific dosing (<i>R</i>²= 0.396-0.409) were obtained than with absolute dose (<i>R</i>²= 0.341). Doses of 101.49 mg (17.81 mg-581.80 mg), 1.57 mg kg^-1(0.42 mg kg^-1-5.82 mg kg^-1), and 23.8 mg l^-1(5.88 mg l^-1-96.17 mg l^-1) were estimated to achieve the required diagnostic CRs of 0.2.<i>Significance.</i>Subject-specific Ferumoxytol dosing based on weight and estimated blood volume provided improved modeling and prediction of vascular suppression in brachial plexus MRN. This helps to optimize dose requirements, improve safety, while providing optimal vascular suppression needed for nerve visualization.</p>","PeriodicalId":20185,"journal":{"name":"Physics in medicine and biology","volume":" ","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145080554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chebyshev-polynomial-based deformable registration of magnetic resonance images with a specific application in adaptive gantry-less proton therapy.","authors":"Hyeongseok Kim, Samantha Hickey, Gregory Buti, Ali Ajdari, Gregory C Sharp, Susu Yan, Thomas Bortfeld","doi":"10.1088/1361-6560/ae077e","DOIUrl":"10.1088/1361-6560/ae077e","url":null,"abstract":"<p><p><i>Objective.</i>Efficient image guidance and online adaptive treatment are essential for the success of gantry-less proton therapy (PT). Low-field magnetic resonance imaging (MRI) is a viable option for image guidance, but scan time can limit the quality of low-field MRI images. This study aims to investigate the impact of MRI image quality on deformable image registration (DIR) performance.<i>Approach.</i>We propose a Chebyshev-polynomial-based DIR method, which calculates a mapping between the voxels of a high-quality source image and a lower-quality target image. We prepared a longitudinal breast MRI dataset and synthesized lower-quality target images with four image resolutions and noise levels. For evaluation, we assumed the registration between a pair of high-quality images as the reference registration. We calculated the root-mean-square error (RMSE) between the warped image and the reference target image, as well as between the warped images aligned with high- and lower-quality target images. Deformable vector field (DVF) errors were calculated based on the reference DVF. We obtained binary masks for glandular tissue and calculated Dice coefficients after DIR. The method was further validated with a volunteer breast MRI study with intentional movements between two scan sets and a longitudinal pelvic MRI dataset that includes two contours. Comparison studies with commercial software and open-source software were performed.<i>Main results.</i>Although the quantitative metrics worsened with higher levels of undersampling or increased noise, the RMSE between the warped and target images was substantially reduced compared to the RMSE between the source and target images before registration, even when the target images were severely degraded. Dice coefficients were also considerably increased under various image degradation scenarios.<i>Significance.</i>We have developed a Chebyshev-polynomial-based DIR method and demonstrated its performance with high-quality source and lower-quality target images. This study could help optimize MRI for adaptive gantry-less PT.</p>","PeriodicalId":20185,"journal":{"name":"Physics in medicine and biology","volume":" ","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145075900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hybrid-MedNet: a hybrid CNN-transformer network with multi-dimensional feature fusion for medical image segmentation.","authors":"Yumna Memon, Feng Zeng","doi":"10.1088/1361-6560/ae0976","DOIUrl":"10.1088/1361-6560/ae0976","url":null,"abstract":"<p><p>Twin-to-twin transfusion syndrome (TTTS) is a complex prenatal condition in which monochorionic twins experience an imbalance in blood flow due to abnormal vascular connections in the shared placenta. Fetoscopic laser photocoagulation is the first-line treatment for TTTS, aimed at coagulating these abnormal connections. However, the procedure is complicated by a limited field of view, occlusions, poor-quality endoscopic images, and distortions caused by artifacts. To optimize the visualization of placental vessels during surgical procedures, we propose Hybrid-MedNet, a novel hybrid CNN-transformer network that incorporates multi-dimensional deep feature learning techniques. The network introduces a BiPath tokenization module that enhances vessel boundary detection by capturing both channel dependencies and spatial features through parallel attention mechanisms. A context-aware transformer block addresses the weak inductive bias problem in traditional transformers while preserving spatial relationships crucial for accurate vessel identification in distorted fetoscopic images. Furthermore, we develop a multi-scale trifusion module that integrates multi-dimensional features to capture rich vascular representations from the encoder and facilitate precise vessel information transfer to the decoder for improved segmentation accuracy. Experimental results show that our approach achieves a Dice score of 95.40% on fetoscopic images, outperforming ten state-of-the-art segmentation methods. The consistent superior performance across four segmentation tasks and ten distinct datasets confirms the robustness and effectiveness of our method for diverse and complex medical imaging applications.</p>","PeriodicalId":20185,"journal":{"name":"Physics in medicine and biology","volume":" ","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145092208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Kidney stone classification by speckle x-ray imaging.","authors":"Werneri A Lindberg, Henning Richter, Fayez Alfayez, Killang Pratama, Olivier Bonny, Damien Terebenec, René M Rossi, Antonia Neels, Robert Zboray","doi":"10.1088/1361-6560/ae09ed","DOIUrl":"10.1088/1361-6560/ae09ed","url":null,"abstract":"<p><p><i>Objective.</i>Urinary stone-related diseases affect approximately 6% of the global population, with nearly half of the patients experiencing recurrence. The diagnosis and management of the disease depend on the stone type and composition. Yet, current clinical imaging modalities (ultrasound, computed tomography, and radiography) lack the sensitivity and specificity required for accurate classification. Speckle-based dark-field x-ray imaging offers a potential non-invasive method for classifying urinary stones with the required hardware simplicity and robustness for potential<i>in vivo</i>, clinical applicability. However, the influence of diffuser masks and state-of-the-art speckle x-ray image retrievals on classification remains underexplored.<i>Approach.</i>This<i>ex vivo</i>study systematically compared the efficacy of custom diffuser masks and state-of-the-art speckle x-ray retrieval algorithms, using both grid and custom speckle masks, for single-shot dark-field imaging in urinary stone classification at high x-ray energy (80 kVp).<i>Main Results.</i>Among the various types of urinary stones examined in this study, canine ammonium urate showed the most distinct visibility contrast difference, deviating by 32%from the average x-ray transmission value. Overall, the results indicate a potential to differentiate between three main groups of urinary stones based on their attenuation-to-scattering coefficients: ammonium urate, calcium-based stones, and a third group comprising cystine and struvite. Regarding the different diffuser masks, the periodic grid mask is found to be the most suitable candidate for application to urinary stones. The different dark-field visibility reduction retrieval algorithms yielded nearly identical classification trends for the urinary stone samples. We recommend nonetheless, the Fokker-Planck-based approach due to its strong physical basis and favorable image quality characteristics, especially if the noise level can be kept low.<i>Significance.</i>The findings in this study establish a technical foundation for advancing speckle-based dark-field x-ray imaging toward clinical translation for non-invasive urinary stone classification.</p>","PeriodicalId":20185,"journal":{"name":"Physics in medicine and biology","volume":" ","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145125887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Predicting lymphocyte dose and surviving fraction for VMAT and IMPT treatments with a dynamic lymphocyte flow model for locally advanced cervical cancer.","authors":"Sander Cyril Kuipers, Marianne van Tuyll van Serooskerken, Danny Lathouwers, Anouk Corbeau, Stephanie M de Boer, Remi A Nout, Mischa S Hoogeman, Jeremy Godart","doi":"10.1088/1361-6560/ae0d29","DOIUrl":"https://doi.org/10.1088/1361-6560/ae0d29","url":null,"abstract":"<p><strong>Objective: </strong>A dynamic model is developed to predict the impact of radiotherapy on circulating lymphocyte counts in women with locally advanced cervical cancer (LACC). This study aims to compare the effects of photon and proton therapy, as well as the influence of bone marrow sparing techniques, on relative lymphocyte preservation over time.&#xD;Approach. A dynamic lymphocyte flow model was developed to simulate the migration of lymphocytes based on seven compartments. Biological cell death and lymphocyte production were integrated across compartments. The lymphocyte flow model was applied to 19 LACC patients. Volumetric modulated arc therapy (VMAT) and intensity modulated proton therapy (IMPT) treatment plans were created for each patient without bone marrow sparing (BMS) and with BMS. The model calculated radiation dose to lymphocytes to estimate radiation-induced cell death over time. The output of the model was the relative lymphocyte count relative to baseline (RLC) over time and the RLC nadir in the blood and total body.&#xD;Main results. According to the model, IMPT resulted in lower doses to lymphocytes and higher RLC nadir than VMAT for all 19 patients. The total RLC nadir (mean ± SD) was 48.4% ± 4.0% for VMAT and 62.5% ± 5.1% for IMPT. In the blood compartment, the RLC nadir was 32.7% ± 3.5% for VMAT and 47.7% ± 5.9% for IMPT. The RLC nadir in the blood compartment improved with 3 Gy BMS from 32.7% ± 3.5% to 33.0% ± 3.5%, while it decreased for IMPT from 47.7% ± 5.9% to 46.6% ± 6.0%. Total RLC nadir decreased with BMS for VMAT from 48.4% ± 4.0% to 48.2% ± 3.9% and for IMPT from 62.5% ± 5.1% to 60.9% ± 5.3%.&#xD;Significance. By incorporating a dynamic flow model, we predicted the RLC over time. The model predicted a substantial sparing effect IMPT has on the lymphocytes compared to VMAT. This sparing was both present in the blood and the total body. Sparing the bone marrow showed only a minimal effect on the RLC.</p>","PeriodicalId":20185,"journal":{"name":"Physics in medicine and biology","volume":" ","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145192403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Automated quantification of cervical spine degeneration with development of a segmentation framework based on probabilistic anatomical cognition.","authors":"Jinge Wang, Siyuan Qin, Ruomu Qu, Feifei Zhou, Ning Lang, Xuefeng Wang","doi":"10.1088/1361-6560/ae023a","DOIUrl":"10.1088/1361-6560/ae023a","url":null,"abstract":"<p><p><i>Objective.</i>Ossification of the posterior longitudinal ligament (OPLL) is a prevalent cervical spine degeneration disease leading to significant spinal cord dysfunctions. Due to morphological diversity and data scarcity, traditional OPLL assessment relies on manual measurements, which suffer from low consistency and high cost. To implement automated quantification of the OPLL, a cognition-inspired segmentation framework, named the probabilistic anatomical cognition (PAC) framework, is proposed to encode physicians' anatomical knowledge of the OPLL and mimic their hierarchical logic of inferring lesions.<i>Approach.</i>The OPLL anatomical structure is firstly modeled by a multi-level probabilistic representation from the stochastic global shape of the spinal canal (SC) to the local feature distributions of the lesions. Based on the anatomical prior model, the OPLL segmentation is implemented by the deep-logic shape inference. The logic extracts high-confidence global feature observations of the SC, following with the inference to the local lesions by morphological correlations. The fusion of the anatomical prior and multi-level observations enhances both interpretability and generalization of lesion segmentation and reduces reliance on large datasets.<i>Main results.</i>Tested on a clinical dataset of 439 patients, the PAC framework improves dice similarity coefficient by 10% over the lightweight baseline and achieves high consistency with expert assessments on clinical lesion metrics.<i>Significance.</i>A general automated segmentation pipeline and three-dimensional metrics are provided for the first time by the framework to quantify the OPLL degeneration, which offers valuable insights to support surgical decision-making.</p>","PeriodicalId":20185,"journal":{"name":"Physics in medicine and biology","volume":" ","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144965091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microdosimetric characterization of a clinical helium beam using a MicroPlus-Bridge detector and a diamond detector for RBE assessment.","authors":"G Petringa, C Verona, A Attili, L Brighel, R Catalano, G A P Cirrone, V C Elia, F Fede, E Formicola, M Guarrera, Y Hamad, A Kurmanova, A Mairani, T Tessonnier, L Manti","doi":"10.1088/1361-6560/ae0862","DOIUrl":"10.1088/1361-6560/ae0862","url":null,"abstract":"<p><p><i>Objective</i>. This study aims to perform a comprehensive microdosimetric characterization of a clinical helium ion beam at the Heidelberg ion-beam Therapy center, assessing radiation quality along a spread-out Bragg peak (SOBP) and providing experimental data to support the biological effectiveness of helium ions in clinical applications.<i>Approach</i>. Microdosimetric spectra were measured at several water depths within the SOBP using two solid-state detectors: a silicon and a synthetic single-crystal diamond detector. Microdosimetric quantities, including dose-mean lineal energy (yD) and frequency-mean lineal energy (yF), were derived. Monte Carlo simulations with the Geant4 toolkit replicated the experimental setup to validate the measured quantities. The modified microdosimetric kinetic model was also applied to estimate the relative biological effectiveness at 10% survival (RBE₁₀). SAOS-2 and U2OS clonogenic assays were performed under identical irradiation conditions at the same facility to benchmark the RBE predictions.<i>Main results</i>. The experimental results demonstrated a progressive increase inyDvalues along the beam path, peaking at the distal edge of the SOBP, consistent with the simulated dose-averaged linear energy transfer distribution. The RBE₁₀values estimated by the two solid-state detectors showed good agreement with the experimental data from clonogenic assays, within the associated uncertainties.<i>Significance</i>. These findings underscore the utility of advanced solid-state detectors for helium beam characterization and highlight the importance of microdosimetry in improving radiobiological modeling. The results provide further evidence supporting the clinical potential of helium ion therapy, particularly for tumors requiring high precision and maximal healthy tissue sparing.</p>","PeriodicalId":20185,"journal":{"name":"Physics in medicine and biology","volume":" ","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145080359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced SVD filter based on singular vector subspace denoising improves ultrafast ultrasound microvascular imaging performance.","authors":"Yu Xia, Jiabin Zhang, Daichao Chen, Jingyi Yin, Hao Yu, Jue Zhang","doi":"10.1088/1361-6560/ae085f","DOIUrl":"10.1088/1361-6560/ae085f","url":null,"abstract":"<p><p><i>Objective</i>. Ultrafast ultrasound imaging can significantly improve the ability of ultrasound for microvascular visualization. Clutter filtering through singular value decomposition (SVD)-based filter remains a pivotal step in Ultrafast ultrasound imaging. However, the current hard threshold-based SVD filter cannot completely separate blood flow from noise on the basis of filtering tissue clutter, resulting in low contrast in microvascular imaging. This paper proposes a novel enhanced SVD (eSVD) filter to enhance blood flow signals and suppress noise while filtering clutter.<i>Approach</i>. The proposed method innovatively partitions spatial singular vectors into multiple blood flow subspaces followed by subspace-specific weighted reconstruction to amplify blood signatures.<i>Main results</i>. We validate the effectiveness of the eSVD filter in contrast-free ultrafast power Doppler imaging (uPDI), contrast-enhanced uPDI, and ultrasound localization microscopy (ULM) imaging experiments. Qualitative and quantitative experimental results show that compared with the hard threshold-based SVD filter, our method can significantly improve the contrast between vessels and background, and highlight the details of microvessels. Compared with the adaptive SVD filter based on the spatial similarity matrix, our eSVD filter improves contrast-to-noise ratio by 8.36 dB, signal-to-noise ratio by 7.92 dB, and blood-to-clutter ratio by 15.47 dB in the uPDI of mouse contrast-free brain. In the ULM of mouse tumor, our eSVD filter improves the global spatial resolution by about 6 <i>µ</i>m, from 34.49 <i>µ</i>m to 28.15 <i>µ</i>m.<i>Significance</i>. The proposed eSVD filter essentially improves the performance of ultrafast ultrasound microvascular imaging and has the potential for the diagnosis of many diseases related to microvessel change.</p>","PeriodicalId":20185,"journal":{"name":"Physics in medicine and biology","volume":" ","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145081386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}