Physics in medicine and biology最新文献

{"title":"Proton GRID and LATTICE treatment planning techniques for clinical liver SFRT treatments.","authors":"Jufri Setianegara, Ya-Nan Zhu, Mingyao Zhu, Rajeev Badkul, Tianyu Zhao, Harold Li, Fen Wang, David Akhavan, Hao Gao, Yuting Lin","doi":"10.1088/1361-6560/add2cc","DOIUrl":"10.1088/1361-6560/add2cc","url":null,"abstract":"<p><p><i>Objective</i>. This study aims to develop and evaluate various treatment clinical proton spatially-fractionated-radiotherapy (pSFRT) planning techniques namely proton GRID (pGRID) and LATTICE (pLATTICE).<i>Approach.</i>pSFRT plans (27 Gy(RBE), single-fraction) were initially developed using phantom geometries and created retrospectively for a liver patient previously treated with photon virtual GRID (vGRID). pGRID plans varied in cylinder diameters (<i>D</i>_cyl= 0.4-1.4 cm) and center-to-center distances (c-t-c = 1.7-3.4 cm) and were evaluated by peak-to-valley dose ratios (PVDRs), equivalent uniform dose (EUD), and<i>V</i>_27Gy.<i>D</i>_cyland c-t-c distances matching the vGRID EUD and<i>V</i>_27Gyvalues guided pLATTICE sphere distributions. Various pLATTICE techniques, including different beam numbers, orientations, and sphere arrangements, were investigated. We also explored using collimating brass apertures to enhance the pGRID PVDR.<i>Main results.</i>pGRID plans with 3.4 cm c-t-c and 0.4 cm<i>D</i>_cylresulted in 2.09%<i>V</i>_27Gy, closely matching vGRID's 1.50%. The resultant pGRID PVDR was 8.92 compared to vGRID's 2.7-3.0. PVDRs were affected by spot sizes with reductions of 15.0% with range shifters and 76.0% from 7.5 cm to 27.5 cm depths. The highest PVDR of 4.17 was achieved with two-field pLATTICE plans with favorable beam angles, with a 44.6% reduction with unfavorable beam orientations and up to 24.7% reductions with an increasing number of beams. Non-maximal pLATTICE sphere packing arrangements increases the PVDR with a decrease in<i>V</i>_27Gywarranting further investigation. pSFRT plans reduced the healthy liver<i>V</i>_5Gyby 83.6%-90.7% compared to vGRID. Apertures enhanced the PVDR by 170% at the deepest depths but increased the skin D_0.03ccfrom 26.77 Gy to 54.66 Gy.<i>Significance and conclusion.</i>We developed pGRID and pLATTICE plans, demonstrating that desired plan metrics was achieved by adjusting the geometrical arrangements of SFRT contours. The relative orientation of these contours with beam entrances was crucial for high-quality SFRT plans. pSFRT plans achieved superior PVDRs and better dose sparing to OARs compared to vGRID plans.</p>","PeriodicalId":20185,"journal":{"name":"Physics in medicine and biology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12087020/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143975705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Angular dependence of detector responses in high-energy brachytherapy.","authors":"Thomas Failing, Rolf Behrens, Frank W Hensley, Boris Keil, Thorsten Schneider, Klemens Zink","doi":"10.1088/1361-6560/adda8c","DOIUrl":"https://doi.org/10.1088/1361-6560/adda8c","url":null,"abstract":"<p><p><b>Objective:</b>To characterize three small volume ionization chambers and a diamond detector concerning their angular dependent response under Ir-192 irradiation.&#xD;<b>Approach:</b>Monte Carlo (MC) simulations and experimental measurements of the angular dependent response were performed at 10cm distance in air. Further simulations were performed at distances of 1-10cm in water. The detectors were placed in relation to their reference points specified by the manufacturer and rotated relative to the beam axis. Results for the different setups were compared to investigate the influence of water and air as well as a distance dependence of angular response. Detector specific properties such as ionization chambers dead volumes or asymmetries were taken into account.&#xD;<b>Main results:</b>The MC simulations in air could be experimentally verified. The detectors showed an angular dependence <0.5% for rotations ≤20°, ≤35°, ≤40° and ≤50° at distances of 1-10cm in water, respectively. In air at 10cm distance, the angular dependence exceeded 0.5% for rotations of 20° for the microDiamond and for 50° for the Semiflex and PinPoint. Here, the angular dependence of the A26 was <0.5% at all angles.&#xD;The slope of the angular dependence increased with rotation from frontal alignment for all detectors. Variations of detector angular dependent response caused by volume averaging were largest close to the source, i.e. up to 8% at 1cm distance. High-Z materials in the vicinity of the sensitive volumes were an additional source of angular response variations amounting up to 4% independent of the distance&#xD;<b>Significance:</b>To the best of the authors' knowledge, this work is the first investigation of perturbation factors, also differential in energy, leading to angular dependent detector response in high-energy brachytherapy dosimetry. The results could be useful to estimate the angular dependent response when measuring complex dose rate distributions, e.g. multiple source positions or in a heterogeneous environment.</p>","PeriodicalId":20185,"journal":{"name":"Physics in medicine and biology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144102389","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":"A validation protocol for¹⁷⁷Lu-SPECT image quantification as a basis for multi-centre kidney dosimetry.","authors":"Lovisa Jessen, Selma Curkic Kapidzic, Johan Gustafsson, Erik Larsson, Michael Ljungberg, Mattias Sandström, Johanna Dalmo, Linn Hagmarker, Cecilia Hindorf, Jan Taprogge, Jonathan Gear, Glenn Flux, Katarina Sjögreen Gleisner","doi":"10.1088/1361-6560/add708","DOIUrl":"10.1088/1361-6560/add708","url":null,"abstract":"<p><p><i>Objective</i>. Multicentre studies in molecular radiotherapy face challenges in ensuring the comparability of dosimetry results. The aim of this study was to develop a validation protocol to achieve equivalent¹⁷⁷Lu-SPECT quantification across centres, consisting of a test exercise in combination with an action level.<i>Approach</i>.¹⁷⁷Lu-SPECT/CT imaging of 3D-printed kidney phantoms with non-uniform activity distributions was conducted at five hospitals in Sweden and the UK. In total, 12 quantification systems (QSs) were included, where a QS was defined as the combination of a given camera system, reconstruction method and image-analysis method. The accuracy of image-based estimates of the activity concentration was investigated for three approaches to multicentre dosimetry: one site-specific, and two variants of centralised approaches. For the site-specific approach, the reference value was blinded to the evaluating operators. Prior to the evaluation, the participants agreed on an action level, specified as an obtained deviation larger than ±10% from the reference value. Sites responsible for a QS that yielded larger deviations, and therefore did not comply, were required to present an action plan, i.e., a plan for further method optimisation.<i>Main results</i>. For the site-specific approach, deviations larger than 10% were obtained for six out of 12 QS (range -11% to +27%). Action plans were presented for these QS and was implemented by one site (two QS). For the two variants of centralised approaches, where nine QS were included in total, deviations of within 10% were obtained for nine and seven QS, respectively.<i>Significance</i>. A quantification test combined with an action level can serve as an initial validation to enable further development and to achieve equivalent¹⁷⁷Lu-SPECT quantification across sites.</p>","PeriodicalId":20185,"journal":{"name":"Physics in medicine and biology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144043671","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":"Exploiting network optimization stability for enhanced PET image denoising using deep image prior.","authors":"Fumio Hashimoto, Kibo Ote, Yuya Onishi, Hideaki Tashima, Go Akamatsu, Yuma Iwao, Miwako Takahashi, Taiga Yamaya","doi":"10.1088/1361-6560/add63f","DOIUrl":"10.1088/1361-6560/add63f","url":null,"abstract":"<p><p><i>Objective</i>. Positron emission tomography (PET) is affected by statistical noise due to constraints on tracer dose and scan duration, impacting both diagnostic performance and quantitative accuracy. While deep learning-based PET denoising methods have been used to improve image quality, they may introduce over-smoothing, which can obscure critical structural details and compromise quantitative accuracy. We propose a method for making a deep learning solution more reliable and apply it to the conditional deep image prior (DIP).<i>Approach</i>. We introduce the idea of<i>stability information</i>in the optimization process of conditional DIP, enabling the identification of unstable regions within the network's optimization trajectory. Our method incorporates a stability map, which is derived from multiple intermediate outputs of a moderate neural network at different optimization steps. The final denoised PET image is then obtained by computing a linear combination of the DIP output and the original reconstructed PET image, weighted by the stability map.<i>Main results</i>. We employed eight high-resolution brain PET datasets for comparison. Our method effectively reduces background noise while preserving small structure details in brain [¹⁸F]FDG PET images. Comparative analysis demonstrated that our approach outperformed existing methods in terms of peak-to-valley ratio and background noise suppression across various low-dose levels. Additionally, region-of-interest analysis confirmed that the proposed method maintains quantitative accuracy without introducing under- or over-estimation. Furthermore, we applied our method to full-dose PET data to assess its impact on image quality. The results revealed that the proposed method significantly reduced background noise while preserving the peak-to-valley ratio at a level comparable to that of unfiltered full-dose PET images.<i>Significance</i>. The proposed method introduces a robust approach to deep learning-based PET denoising, enhancing its reliability and preserving quantitative accuracy. Furthermore, this strategy can potentially advance performance in high-sensitivity PET scanners and surpass the limit of image quality inherent to PET scanners.</p>","PeriodicalId":20185,"journal":{"name":"Physics in medicine and biology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144035607","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":"Photon-counting CT in cancer radiotherapy: technological advances and clinical benefits.","authors":"Keyur D Shah, Jun Zhou, Justin Roper, Anees Dhabaan, Hania Al-Hallaq, Amir Pourmorteza, Xiaofeng Yang","doi":"10.1088/1361-6560/add4ba","DOIUrl":"10.1088/1361-6560/add4ba","url":null,"abstract":"<p><p>Photon-counting computed tomography (PCCT) marks a significant advancement over conventional Energy-integrating detector CT systems. This review highlights PCCT's superior spatial and contrast resolution, reduced radiation dose, and multi-energy imaging capabilities, which address key challenges in radiotherapy, such as accurate tumor delineation, precise dose calculation, and treatment response monitoring. PCCT's improved anatomical clarity enhances tumor targeting while minimizing damage to surrounding healthy tissues. Additionally, Metal artifact reduction and quantitative imaging capabilities optimize workflows, enabling ART and radiomics-driven personalized treatment. Emerging clinical applications in brachytherapy and radiopharmaceutical therapy show promising outcomes, although challenges like high costs and limited software integration remain. With advancements in artificial intelligence and dedicated radiotherapy packages, PCCT is poised to transform precision, safety, and efficacy in cancer radiotherapy, marking it as a pivotal technology for future clinical practice.</p>","PeriodicalId":20185,"journal":{"name":"Physics in medicine and biology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12086776/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144043163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Patient-specific uncertainty calibration of deep learning-based autosegmentation networks for adaptive MRI-guided lung radiotherapy.","authors":"Moritz Rabe, Ettore F Meliadò, Sebastian N Marschner, Claus Belka, Stefanie Corradini, Cornelis A T van den Berg, Guillaume Landry, Christopher Kurz","doi":"10.1088/1361-6560/add640","DOIUrl":"10.1088/1361-6560/add640","url":null,"abstract":"<p><p><i>Objective.</i>Uncertainty assessment of deep learning autosegmentation (DLAS) models can support contour corrections in adaptive radiotherapy (ART), e.g. by utilizing Monte Carlo Dropout (MCD) uncertainty maps. However, poorly calibrated uncertainties at the patient level often render these clinically nonviable. We evaluated population-based and patient-specific DLAS accuracy and uncertainty calibration and propose a patient-specific post-training uncertainty calibration method for DLAS in ART.<i>Approach.</i>The study included 122 lung cancer patients treated with a low-field MR-linac (80/19/23 training/validation/test cases). Ten single-label 3D-U-Net population-based baseline models (BM) were trained with dropout using planning MRIs (pMRIs) and contours for nine organs-at-riks (OARs) and gross tumor volumes (GTVs). Patient-specific models (PS) were created by fine-tuning BMs with each test patient's pMRI. Model uncertainty was assessed with MCD, averaged into probability maps. Uncertainty calibration was evaluated with reliability diagrams and expected calibration error (ECE). A proposed post-training calibration method rescaled MCD probabilities for fraction images in BM (calBM) and PS (calPS) after fitting reliability diagrams from pMRIs. All models were evaluated on fraction images using Dice similarity coefficient (DSC), 95th percentile Hausdorff distance (HD95) and ECE. Metrics were compared among models for all OARs combined (<i>n</i> = 163), and the GTV (<i>n</i> = 23), using Friedman and posthoc-Nemenyi tests (<i>α</i> = 0.05).<i>Main results.</i>For the OARs, patient-specific fine-tuning significantly (<i>p</i> < 0.001) increased median DSC from 0.78 (BM) to 0.86 (PS) and reduced HD95 from 14 mm (BM) to 6.0 mm (PS). Uncertainty calibration achieved substantial reductions in ECE, from 0.25 (BM) to 0.091 (calBM) and 0.22 (PS) to 0.11 (calPS) (<i>p</i> < 0.001), without significantly affecting DSC or HD95 (<i>p</i> > 0.05). For the GTV, BM performance was poor (DSC = 0.05) but significantly (<i>p</i> < 0.001) improved with PS training (DSC = 0.75) while uncertainty calibration reduced ECE from 0.22 (PS) to 0.15 (calPS) (<i>p</i> = 0.45).<i>Significance.</i>Post-training uncertainty calibration yields geometrically accurate DLAS models with well-calibrated uncertainty estimates, crucial for ART applications.</p>","PeriodicalId":20185,"journal":{"name":"Physics in medicine and biology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144039959","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":"TOPAS-nBio-Reg: a regression testing system for track structure simulations in TOPAS-nBio.","authors":"Thongchai A M Masilela, Naoki D-Kondo, Wook-Geun Shin, Ramon Ortiz, Isaac Meyer, Jay A LaVerne, Bruce Faddegon, Jan Schuemann, José Ramos-Méndez","doi":"10.1088/1361-6560/add4b9","DOIUrl":"10.1088/1361-6560/add4b9","url":null,"abstract":"<p><p><i>Objective.</i>To develop a regression testing system for TOPAS-nBio: a wrapper of Geant4-DNA, and the radiobiological extension of TOPAS-a Monte Carlo code for the simulation of radiation transport. This regression testing system will be made publicly available on the TOPAS-nBio GitHub page.<i>Approach.</i>A set of seven regression tests were chosen to evaluate the suite of capabilities of TOPAS-nBio from both a physical and chemical point of view. Three different versions of the code were compared: TOPAS-nBio-v2.0 (the previous version), TOPAS-nBio-v3.0 (the current public release), and TOPAS-nBio-v4.0 (the current developer version, planned for future release). The main aspects compared for each test were the differences in execution times, variations from other versions of TOPAS-nBio, and agreement with measurements/in silico data.<i>Main results.</i>Execution times of nBio-v3.0 for all physics tests were faster than those of nBio-v2.0 due to the use of a new Geant4 version. Mean point-to-point differences between TOPAS-nBio versions across all tests fell largely within 5%. The exceptions were the radiolytic yields (<i>G</i>values) ofH2andH2O2, which differed moderately (16% and 10% respectively) when going from nBio-v3.0 to nBio-v4.0. In all cases a good agreement with other experimental/simulated data was obtained.<i>Significance.</i>From a developer point of view, this regression testing system is essential as it allows a more rigorous reporting of the consequences of new version releases on quantities such as the LET or<i>G</i>values of chemical species. Furthermore, it enables us to test 'pushes' made to the codebase by collaborators and contributors. From an end-user point of view, users of the software are now able to easily evaluate how changes in the source code, made for their specific application, would affect the results of known quantities.</p>","PeriodicalId":20185,"journal":{"name":"Physics in medicine and biology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144036893","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":"Therapeutic enhancement effects using a lower energy 2.5 MV photon beam combined with gold nanoparticles on the BxPC-3 pancreatic cancer cell line,<i>in vitro</i>.","authors":"Xiao Qing Yao, Sarah A Sabatinos, Eric Da Silva, Amandeep Taggar, Diana Ha, Rao Khan, Raffi Karshafian, James Gräfe","doi":"10.1088/1361-6560/add4b8","DOIUrl":"10.1088/1361-6560/add4b8","url":null,"abstract":"<p><p><i>Objective</i>. This study investigates the feasibility of using a clinically relevant lower energy 2.5 megavoltage (MV) photon beam in combination with gold nanoparticles (GNPs).<i>Approach.</i>Pancreatic cancer cell line, BxPC-3 impregnated with GNPs were exposed<i>in vitro</i>to 2.5 MV photon beam and compared with orthovoltage 225 kV and clinical 6 MV photon beam. Bare, 50 nm diameter, spherical GNPs were introduced in the cell culture 24 h prior to irradiation at a concentration of either 10<i>μ</i>g ml^-1or 50<i>μ</i>g ml^-1. GNP uptake was determined using inductively coupled plasma optical emission spectroscopy. The cells were irradiated with doses between 0 Gy to 8 Gy. Cell survival curves were obtained via clonogenic assay using immediate or delayed plating (24 h) methods 12 d after irradiation. The terminal deoxynucleotidyl transferase dUTP nick end labeling assay was used to evaluate DNA damage at two time points post irradiation, immediate and 24 h for 1 Gy and 6 Gy.<i>Main results</i>. The enhancement factor (EF) in BxPC-3 cells was greatest for cells incubated with 50<i>μ</i>g ml^-1of GNPs analyzed immediately post irradiation. Cells irradiated with 225 kV showed greatest EF (1.57 ± 0.15), followed by 2.5 MV (1.51 ± 0.04). The lowest EF was seen for 6 MV, immediate plating (1.10 ± 0.04). A significant increase in the number of DNA double strand breaks (DSB) was observed in cells incubated with 50<i>μ</i>g ml^-1of GNPs irradiated at 6 Gy with 225 kV and 2.5 MV. There was no significant increase in DSBs for the cells irradiated with 6 MV.<i>Significance.</i>These results suggest that the 2.5 MV could be a compromise between an orthovoltage energy beam and a clinical 6 MV beam, showing comparable reduction in cell survival to the 225 kV beam. Future GNP radiation enhancement research may focus on intermediate energy beams.</p>","PeriodicalId":20185,"journal":{"name":"Physics in medicine and biology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144036163","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":"A coil-channel multiplexer for high-density receive arrays compatible with the MR-linac.","authors":"Tom Bosma, Jan G M Kok, Pim T S Borman, Cornelis A T van den Berg, Martin F Fast","doi":"10.1088/1361-6560/add3b7","DOIUrl":"https://doi.org/10.1088/1361-6560/add3b7","url":null,"abstract":"<p><p><i>Objective.</i>We present a prototype add-on multiplexer for retro-fitting high-channel count receive coils onto systems with analog readout chains, such as the MR-linac. This particular system is currently equipped with two coil elements, containing only four channels each.<i>Approach.</i>We developed a 4:1 multiplexer board based on time-division. CMOS-based single-pole double-throw switches were used to accommodate for fast switching and adequate encoding bandwidths. Coil-channel images were separated after reconstruction by solving a system of equations based on the square-wave modulation imposed by the multiplexer. The prototype was tested at a 1.5 T scanner on an image-quality phantom and a slice of bovine muscle using four coil channels from a previously characterized 16-channel anterior coil prototype.<i>Main results.</i>The image data received through multiplexing could be reliably divided into separate coil-channel images, preserving the coil sensitivity maps. Leakage between channels remained below -30 dB. In each coil channel the signal-to-noise ratio was penalized by a factor of two compared to direct digitization due to the inflicted data compression. Furthermore, it was shown that the<i>g</i>-factor for parallel imaging remained largely unaffected by multiplexing. Imaging speedup is expected with this multiplexer, since a fourfold channel-count increase typically yields<i>g</i>-factor improvements that are superior to the signal-quality reduction.<i>Significance.</i>A 4:1 coil-channel add-on multiplexer was developed and its functionality demonstrated in the MR readout chain at 1.5 T. We expect that this solution will enable significant imaging speedup for clinical MR systems that suffer from compatibility with a limited number of channels for the receive coil array.</p>","PeriodicalId":20185,"journal":{"name":"Physics in medicine and biology","volume":"70 10","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144028769","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":"A robust framework with knowledge-guided planning and fiducial-based registration for bronchoscopy navigation system.","authors":"Haixing Zhu, Zhongjie Shi, Wenbo Zhai, Yifei Liu, Yuan Wang, Zimo Bai, Zhanxiang Wang, Rining Wu, Weipeng Liu","doi":"10.1088/1361-6560/add8dc","DOIUrl":"https://doi.org/10.1088/1361-6560/add8dc","url":null,"abstract":"<p><strong>Objective: </strong>Bronchoscopy is a valuable minimally invasive examination in clinical practice and is widely used in the diagnosis of suspected peripheral lung lesions. However, this device has difficulty in accessing peripheral areas from lack of inadequate guidance and heavily relies on intraoperative X-ray or computerized tomography (CT) scan.</p><p><strong>Approach: </strong>In order to overcome these limitations, we propose a robust navigation framework with knowledge-guided planning and fiducial-based registration for bronchoscopy navigation, which makes three notable contributions that have been experimentally verified to be of practical value. Firstly, we propose a preoperative path-planning algorithm with anatomical prior knowledge to generate a feasible and accurate trajectory. Secondly, a fiducial-based patient-image registration scheme is&#xD;introduced to align virtual images with the patient's actual anatomy, building a robust rigid relationship and enabling real-time updates. Thirdly, we establish a position sensing approach to present precise positions and track the movement of the bronchoscope.</p><p><strong>Main results: </strong>Extensive experiments on the 3D-printed airway tree model and in vivo porcine lung are conducted to evaluate comprehensive capabilities. Qualitative and quantitative results manifest that our framework can achieve excellent&#xD;performance, reaching a success rate of 100% in the path-planning stage, achieving robust registration precision with a fiducial registration error (FRE) of 0.998 ± 0.074 mm, and obtaining the standard deviation of 0.017 mm, 0.206 mm and 0.013 mm in the tracking stage.</p><p><strong>Significance: </strong>Our results demonstrate the feasibility and effectiveness and further has potential prospects as an auxiliary tool to extend the capabilities of clinical bronchoscopy.</p>","PeriodicalId":20185,"journal":{"name":"Physics in medicine and biology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144079571","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}