Detecting the specificity of cancer cells to distinguish them from normal ones is an important step in the general framework of cancer diagnosis. A routine example of such diagnosis in cancerous tissues implies using microscope analysis of fixed, paraffined, and colored slices such as the H&E stain (1). Such a method, which takes place after surgery, is based on carefully analyzing the cell's size and shape. Often, this approach is performed in parallel with more modern genetic tests. Recent research has hypothesized that extrachromosomal circular DNA (eccDNA) could be considered a new hallmark of cancer (4). Thus, this research aims to check if using a simple, label-free microscope dynamic analysis performed on living cancer cells would allow efficient and simpler detection of cancer cells.
{"title":"Full Field Transmission Tomography (FFOTT) for imaging extrachromosomal circular DNA (eccDNA) in cancer cell nuclei","authors":"Nathan Boccara, Samer Alhaddad, Viacheslav Mazlin","doi":"arxiv-2408.15736","DOIUrl":"https://doi.org/arxiv-2408.15736","url":null,"abstract":"Detecting the specificity of cancer cells to distinguish them from normal\u0000ones is an important step in the general framework of cancer diagnosis. A\u0000routine example of such diagnosis in cancerous tissues implies using microscope\u0000analysis of fixed, paraffined, and colored slices such as the H&E stain (1).\u0000Such a method, which takes place after surgery, is based on carefully analyzing\u0000the cell's size and shape. Often, this approach is performed in parallel with\u0000more modern genetic tests. Recent research has hypothesized that\u0000extrachromosomal circular DNA (eccDNA) could be considered a new hallmark of\u0000cancer (4). Thus, this research aims to check if using a simple, label-free\u0000microscope dynamic analysis performed on living cancer cells would allow\u0000efficient and simpler detection of cancer cells.","PeriodicalId":501378,"journal":{"name":"arXiv - PHYS - Medical Physics","volume":"46 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142176645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Banghao ZhouBiomedical Imaging and Radiation Technology Laboratory, Lixiang GuoBiomedical Imaging and Radiation Technology Laboratory, Weiguo LuDepartment of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA, Mahbubur RahmanDepartment of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA, Rongxiao ZhangDepartment of Radiation Medicine, New York Medical College, Valhalla, NY, Varghese Anto ChirayathDepartment of Physics, College of Science, The University of Texas at Arlington, Arlington, TX, USA, Yang Kyun ParkDepartment of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA, Strahinja StojadinovicDepartment of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA, Marvin GarzaDepartment of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA, Ken Kang-Hsin WangBiomedical Imaging and Radiation Technology Laboratory
Background: FLASH radiotherapy is a treatment regime that delivers therapeutic dose to tumors at an ultra-high dose rate while maintaining adequate normal tissue sparing. However, a comprehensive understanding of the underlying mechanisms, potential late toxicities, and optimal fractionation schemes is important for successful clinical translation. This has necessitated extensive pre-clinical investigations, leading several research institutions to initiate dedicated FLASH research programs. Purpose: This work describes a workflow for establishing an easily accessible electron FLASH (eFLASH) platform. The platform incorporates simplified pulse control, optimized dose rate delivery, and validated Monte Carlo (MC) dose engine for accurate in vivo dosimetry dedicated to FLASH pre-clinical studies. Methods: Adjustment of the automatic frequency control (AFC) module allowed us to optimize the LINAC pulse form to achieve a uniform dose rate. A MC model for the 6 MeV FLASH beam was commissioned to ensure accurate dose calculation necessary for reproducible in vivo studies. Results: Optimizing the AFC module enabled the generation of a uniform pulse form, ensuring consistent dose per pulse and a uniform dose rate throughout FLASH irradiation. The MC model closely agreed with film measurements. MC dose calculations indicated that 6 MeV FLASH is adequate to achieve a uniform dose distribution for mouse whole brain irradiation but may not be optimal for the spinal cord study. Conclusions: We present a novel workflow for establishing a LINAC-based eFLASH research platform, incorporating techniques for optimized dose rate delivery, a simplified pulse control system, and validated MC engine. This work provides researchers with valuable new approaches to facilitate the development of robust and accessible LINAC-based system for FLASH studies.
{"title":"Electron FLASH platform for pre-clinical research: LINAC modification, simplification of pulse control and dosimetry","authors":"Banghao ZhouBiomedical Imaging and Radiation Technology Laboratory, Lixiang GuoBiomedical Imaging and Radiation Technology Laboratory, Weiguo LuDepartment of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA, Mahbubur RahmanDepartment of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA, Rongxiao ZhangDepartment of Radiation Medicine, New York Medical College, Valhalla, NY, Varghese Anto ChirayathDepartment of Physics, College of Science, The University of Texas at Arlington, Arlington, TX, USA, Yang Kyun ParkDepartment of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA, Strahinja StojadinovicDepartment of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA, Marvin GarzaDepartment of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA, Ken Kang-Hsin WangBiomedical Imaging and Radiation Technology Laboratory","doi":"arxiv-2408.15426","DOIUrl":"https://doi.org/arxiv-2408.15426","url":null,"abstract":"Background: FLASH radiotherapy is a treatment regime that delivers\u0000therapeutic dose to tumors at an ultra-high dose rate while maintaining\u0000adequate normal tissue sparing. However, a comprehensive understanding of the\u0000underlying mechanisms, potential late toxicities, and optimal fractionation\u0000schemes is important for successful clinical translation. This has necessitated\u0000extensive pre-clinical investigations, leading several research institutions to\u0000initiate dedicated FLASH research programs. Purpose: This work describes a\u0000workflow for establishing an easily accessible electron FLASH (eFLASH)\u0000platform. The platform incorporates simplified pulse control, optimized dose\u0000rate delivery, and validated Monte Carlo (MC) dose engine for accurate in vivo\u0000dosimetry dedicated to FLASH pre-clinical studies. Methods: Adjustment of the\u0000automatic frequency control (AFC) module allowed us to optimize the LINAC pulse\u0000form to achieve a uniform dose rate. A MC model for the 6 MeV FLASH beam was\u0000commissioned to ensure accurate dose calculation necessary for reproducible in\u0000vivo studies. Results: Optimizing the AFC module enabled the generation of a\u0000uniform pulse form, ensuring consistent dose per pulse and a uniform dose rate\u0000throughout FLASH irradiation. The MC model closely agreed with film\u0000measurements. MC dose calculations indicated that 6 MeV FLASH is adequate to\u0000achieve a uniform dose distribution for mouse whole brain irradiation but may\u0000not be optimal for the spinal cord study. Conclusions: We present a novel\u0000workflow for establishing a LINAC-based eFLASH research platform, incorporating\u0000techniques for optimized dose rate delivery, a simplified pulse control system,\u0000and validated MC engine. This work provides researchers with valuable new\u0000approaches to facilitate the development of robust and accessible LINAC-based\u0000system for FLASH studies.","PeriodicalId":501378,"journal":{"name":"arXiv - PHYS - Medical Physics","volume":"181 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142176651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Qiaoxin Li, Ruifeng Chen, Peng Wang, Guotao Quan, Yanfeng Du, Dong Liang, Yinsheng Li
Dual-energy computed tomography (DECT) has been widely used to obtain quantitative elemental composition of imaged subjects for personalized and precise medical diagnosis. Compared with DECT leveraging advanced X-ray source and/or detector technologies, the use of the sequential-scanning data acquisition scheme to implement DECT may make a broader impact on clinical practice because this scheme requires no specialized hardware designs and can be directly implemented into conventional CT systems. However, since the concentration of iodinated contrast agent in the imaged subject varies over time, sequentially scanned data sets acquired at two tube potentials are temporally inconsistent. As existing material basis image reconstruction approaches assume that the data sets acquired at two tube potentials are temporally consistent, the violation of this assumption results in inaccurate quantification of material concentration. In this work, we developed sequential-scanning DECT imaging using high temporal resolution image reconstruction and error-compensated material basis image generation, ACCELERATION in short, to address the technical challenge induced by temporal inconsistency of sequentially scanned data sets and improve quantification accuracy of material concentration in sequential-scanning DECT. ACCELERATION has been validated and evaluated using numerical simulation data sets generated from clinical human subject exams and experimental human subject studies. Results demonstrated the improvement of quantification accuracy and image quality using ACCELERATION.
{"title":"Sequential-Scanning Dual-Energy CT Imaging Using High Temporal Resolution Image Reconstruction and Error-Compensated Material Basis Image Generation","authors":"Qiaoxin Li, Ruifeng Chen, Peng Wang, Guotao Quan, Yanfeng Du, Dong Liang, Yinsheng Li","doi":"arxiv-2408.14754","DOIUrl":"https://doi.org/arxiv-2408.14754","url":null,"abstract":"Dual-energy computed tomography (DECT) has been widely used to obtain\u0000quantitative elemental composition of imaged subjects for personalized and\u0000precise medical diagnosis. Compared with DECT leveraging advanced X-ray source\u0000and/or detector technologies, the use of the sequential-scanning data\u0000acquisition scheme to implement DECT may make a broader impact on clinical\u0000practice because this scheme requires no specialized hardware designs and can\u0000be directly implemented into conventional CT systems. However, since the\u0000concentration of iodinated contrast agent in the imaged subject varies over\u0000time, sequentially scanned data sets acquired at two tube potentials are\u0000temporally inconsistent. As existing material basis image reconstruction\u0000approaches assume that the data sets acquired at two tube potentials are\u0000temporally consistent, the violation of this assumption results in inaccurate\u0000quantification of material concentration. In this work, we developed\u0000sequential-scanning DECT imaging using high temporal resolution image\u0000reconstruction and error-compensated material basis image generation,\u0000ACCELERATION in short, to address the technical challenge induced by temporal\u0000inconsistency of sequentially scanned data sets and improve quantification\u0000accuracy of material concentration in sequential-scanning DECT. ACCELERATION\u0000has been validated and evaluated using numerical simulation data sets generated\u0000from clinical human subject exams and experimental human subject studies.\u0000Results demonstrated the improvement of quantification accuracy and image\u0000quality using ACCELERATION.","PeriodicalId":501378,"journal":{"name":"arXiv - PHYS - Medical Physics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142176652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Azam Zabihi, Xinran Li, Alejandro Ramirez, Manuel D. Da Rocha Rolo, Davide Franco, Federico Gabriele, Cristiano Galbiati, Michela Lai, Daniel R. Marlow, Andrew Renshaw, Shawn Westerdale, Masayuki Wada
Objective: This paper introduces a novel PET imaging methodology called 3-dimensional positron imaging (3D{pi}), which integrates total-body (TB) coverage, time-of-flight (TOF) technology, ultra-low dose imaging capabilities, and ultra-fast readout electronics inspired by emerging technology from the DarkSide collaboration. Approach: The study evaluates the performance of 3D{pi} using Monte Carlo simulations based on NEMA NU 2-2018 protocols. The methodology employs a homogenous, monolithic scintillator composed of liquid argon (LAr) doped with xenon (Xe) with silicon photomultipliers (SiPM) operating at cryogenic temperatures. Main results: Significant enhancements in system performance are observed, with the 3D{pi} system achieving a noise equivalent count rate (NECR) of 3.2 Mcps which is approximately two times higher than uEXPLORER's peak NECR (1.5 Mcps) at 17.3 (kBq/mL). Spatial resolution measurements show an average FWHM of 2.7 mm across both axial positions. The system exhibits superior sensitivity, with values reaching 373 kcps/MBq with a line source at the center of the field of view. Additionally, 3D{pi} achieves a TOF resolution of 151 ps at 5.3 kBq/mL, highlighting its potential to produce high-quality images with reduced noise levels. Significance: The study underscores the potential of 3D{pi} in improving PET imaging performance, offering the potential for shorter scan times and reduced radiation exposure for patients. The Xe-doped LAr offers advantages such as fast scintillation, enhanced light yield, and cost-effectiveness. Future research will focus on optimizing system geometry and further refining reconstruction algorithms to exploit the strengths of 3D{pi} for clinical applications.
目的：本文介绍了一种名为三维正电子成像（3D{pi}）的新型 PET 成像方法，它集成了全身（TB）覆盖、飞行时间（TOF）技术、超低剂量成像能力和超快读出电子装置，其灵感来自于黑暗面合作组织（DarkSide collaboration）的新兴技术。方法：该研究使用基于NEMA NU 2-2018协议的蒙特卡罗模拟来评估3D{pi}的性能。该方法采用了由掺杂氙（Xe）的液氩（LAr）和在低温下工作的硅光电倍增管（SiPM）组成的同质单片闪烁器。主要结果：观察到系统性能显著提高，3D{pi}系统的噪声等效计数率（NECR）达到了3.2 Mcps，比uEXPLORER在17.3（kBq/mL）时的峰值NECR（1.5 Mcps）高出约两倍。空间分辨率测量显示，两个轴向位置的平均 FWHM 为 2.7 毫米。该系统显示出卓越的灵敏度，在视场中心的线源上，灵敏度值达到 373kcps/MBq。此外，3D{pi} 在 5.3 kBq/mL 时实现了 151 ps 的 TOF 分辨率，凸显了其在降低噪声水平的同时生成高质量图像的潜力：这项研究强调了 3D{pi} 在提高 PET 成像性能方面的潜力，为缩短扫描时间和减少患者的辐射暴露提供了可能。掺Xe的LAr具有快速闪烁、提高光产率和成本效益等优势。未来的研究将侧重于优化系统几何结构和进一步完善重建算法，以发挥三维{pi}在临床应用中的优势。
{"title":"3Dπ: Three-Dimensional Positron Imaging, A Novel Total-Body PET Scanner Using Xenon-Doped Liquid Argon Scintillator","authors":"Azam Zabihi, Xinran Li, Alejandro Ramirez, Manuel D. Da Rocha Rolo, Davide Franco, Federico Gabriele, Cristiano Galbiati, Michela Lai, Daniel R. Marlow, Andrew Renshaw, Shawn Westerdale, Masayuki Wada","doi":"arxiv-2408.14645","DOIUrl":"https://doi.org/arxiv-2408.14645","url":null,"abstract":"Objective: This paper introduces a novel PET imaging methodology called\u00003-dimensional positron imaging (3D{pi}), which integrates total-body (TB)\u0000coverage, time-of-flight (TOF) technology, ultra-low dose imaging capabilities,\u0000and ultra-fast readout electronics inspired by emerging technology from the\u0000DarkSide collaboration. Approach: The study evaluates the performance of\u00003D{pi} using Monte Carlo simulations based on NEMA NU 2-2018 protocols. The\u0000methodology employs a homogenous, monolithic scintillator composed of liquid\u0000argon (LAr) doped with xenon (Xe) with silicon photomultipliers (SiPM)\u0000operating at cryogenic temperatures. Main results: Significant enhancements in\u0000system performance are observed, with the 3D{pi} system achieving a noise\u0000equivalent count rate (NECR) of 3.2 Mcps which is approximately two times\u0000higher than uEXPLORER's peak NECR (1.5 Mcps) at 17.3 (kBq/mL). Spatial\u0000resolution measurements show an average FWHM of 2.7 mm across both axial\u0000positions. The system exhibits superior sensitivity, with values reaching 373\u0000kcps/MBq with a line source at the center of the field of view. Additionally,\u00003D{pi} achieves a TOF resolution of 151 ps at 5.3 kBq/mL, highlighting its\u0000potential to produce high-quality images with reduced noise levels.\u0000Significance: The study underscores the potential of 3D{pi} in improving PET\u0000imaging performance, offering the potential for shorter scan times and reduced\u0000radiation exposure for patients. The Xe-doped LAr offers advantages such as\u0000fast scintillation, enhanced light yield, and cost-effectiveness. Future\u0000research will focus on optimizing system geometry and further refining\u0000reconstruction algorithms to exploit the strengths of 3D{pi} for clinical\u0000applications.","PeriodicalId":501378,"journal":{"name":"arXiv - PHYS - Medical Physics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142176653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Florian FichotIRSN/PSN-RES/SAM/LEPC, Laure CaréniniIRSN/PSN-RES/SAM/LEPC, Stephan BrummJRC, Marco SangiorgiJRC
Molten corium stabilization following a severe accident is of crucial importance in order to ensure containment integrity on a long-term basis and minimizing radioactive elements releases outside the plant. Among the possible options, In-Vessel Retention (IVR) through external cooling appears as an attractive solution that would limit the dispersion of corium in the plant and minimize the risks of containment failure. Nevertheless its feasibility has to be proved.The IVR strategy is already adopted in Europe for some VVER 440 type 213 reactors thanks to thorough research work started in the '90s for the Finnish Loviisa power plant, and subsequently extended to Bohunice and Mochovce (Slovakia), Dukovany (Czech Republic) and Paks (Hungary) power plants. The strategy is also included in the design of some high power new Gen.III reactors such as AP1000, APR 1400 and Chinese HPR1000 and CAP1400. It has also been studied in the past for other reactor concepts like KERENA (1250 MWe - BWR), AP600 or VVER-640.Current approaches for reactors with relatively small power, such as VVER 440 or AP600, use conservative assumptions for the safety demonstration. However, for higher power reactors (around 1000 MWe), the safety margin is reduced and it is necessary to evaluate the IVR strategy with best-estimate methods in order to reduce the uncertainties associated with the involved phenomena. Additional R&D as well as a revision of the methodology are needed to ensure and demonstrate adequate safety margins, including, in particular, best-estimate evaluations of thermal load applied on the vessel and mechanical resistance of the ablated vessel.The IVMR project (In-Vessel Melt Retention) was built with the goal of providing new knowledge (experimental, theoretical and technical) and a new methodology able to provide a best-estimate evaluation of IVR strategy for large power reactors. The main objective of Task 2.1 within WP2 was to define a common methodology to analyse IVR Severe Accident Management (SAM) strategy for the different types of EU NPPs. It started by reviewing the status of existing methodology and aimed at elaborating a more general, updated and less conservative one applicable to several types of reactors.This paper describes the proposed new methodology. It starts with the identification of the deficiencies of the standard methodology when it is applied to a high power reactor. It introduces the minimum vessel thickness as a parameter representing the cumulated imbalance between internal heat load and external cooling. Then it explains how to use that parameter in the evaluation of the safety margin. Although some examples are given as illustrations, it must be kept in mind that this paper proposes a generic methodology but there cannot be any generic conclusion: any reactor design must be evaluated independently.
{"title":"Methodology of safety evaluation of In-Vessel Retention","authors":"Florian FichotIRSN/PSN-RES/SAM/LEPC, Laure CaréniniIRSN/PSN-RES/SAM/LEPC, Stephan BrummJRC, Marco SangiorgiJRC","doi":"arxiv-2408.14522","DOIUrl":"https://doi.org/arxiv-2408.14522","url":null,"abstract":"Molten corium stabilization following a severe accident is of crucial\u0000importance in order to ensure containment integrity on a long-term basis and\u0000minimizing radioactive elements releases outside the plant. Among the possible\u0000options, In-Vessel Retention (IVR) through external cooling appears as an\u0000attractive solution that would limit the dispersion of corium in the plant and\u0000minimize the risks of containment failure. Nevertheless its feasibility has to\u0000be proved.The IVR strategy is already adopted in Europe for some VVER 440 type\u0000213 reactors thanks to thorough research work started in the '90s for the\u0000Finnish Loviisa power plant, and subsequently extended to Bohunice and Mochovce\u0000(Slovakia), Dukovany (Czech Republic) and Paks (Hungary) power plants. The\u0000strategy is also included in the design of some high power new Gen.III reactors\u0000such as AP1000, APR 1400 and Chinese HPR1000 and CAP1400. It has also been\u0000studied in the past for other reactor concepts like KERENA (1250 MWe - BWR),\u0000AP600 or VVER-640.Current approaches for reactors with relatively small power,\u0000such as VVER 440 or AP600, use conservative assumptions for the safety\u0000demonstration. However, for higher power reactors (around 1000 MWe), the safety\u0000margin is reduced and it is necessary to evaluate the IVR strategy with\u0000best-estimate methods in order to reduce the uncertainties associated with the\u0000involved phenomena. Additional R&D as well as a revision of the methodology are\u0000needed to ensure and demonstrate adequate safety margins, including, in\u0000particular, best-estimate evaluations of thermal load applied on the vessel and\u0000mechanical resistance of the ablated vessel.The IVMR project (In-Vessel Melt\u0000Retention) was built with the goal of providing new knowledge (experimental,\u0000theoretical and technical) and a new methodology able to provide a\u0000best-estimate evaluation of IVR strategy for large power reactors. The main\u0000objective of Task 2.1 within WP2 was to define a common methodology to analyse\u0000IVR Severe Accident Management (SAM) strategy for the different types of EU\u0000NPPs. It started by reviewing the status of existing methodology and aimed at\u0000elaborating a more general, updated and less conservative one applicable to\u0000several types of reactors.This paper describes the proposed new methodology. It\u0000starts with the identification of the deficiencies of the standard methodology\u0000when it is applied to a high power reactor. It introduces the minimum vessel\u0000thickness as a parameter representing the cumulated imbalance between internal\u0000heat load and external cooling. Then it explains how to use that parameter in\u0000the evaluation of the safety margin. Although some examples are given as\u0000illustrations, it must be kept in mind that this paper proposes a generic\u0000methodology but there cannot be any generic conclusion: any reactor design must\u0000be evaluated independently.","PeriodicalId":501378,"journal":{"name":"arXiv - PHYS - Medical Physics","volume":"150 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142176656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Maximilian Rixner, Maximilian Ludwig, Matthias Lindner, Inéz Frerichs, Armin Sablewski, Karl-Robert Wichmann, Max-Carl Wachter, Kei W. Müller, Dirk Schädler, Wolfgang A. Wall, Jonas Biehler, Tobias Becher
The choice of lung protective ventilation settings for mechanical ventilation has a considerable impact on patient outcome, yet identifying optimal ventilatory settings for individual patients remains highly challenging due to the inherent inter- and intra-patient pathophysiological variability. In this validation study, we demonstrate that physics-based computational lung models tailored to individual patients can resolve this variability, allowing us to predict the otherwise unknown local state of the pathologically affected lung during mechanical ventilation. For seven ARDS patients undergoing invasive mechanical ventilation, physics-based, patient-specific lung models were created using chest CT scans and ventilatory data. By numerically resolving the interaction of the pathological lung with the airway pressure and flow imparted by the ventilator, we predict the time-dependent and heterogeneous local state of the lung for each patient and compare it against the regional ventilation obtained from bedside monitoring using Electrical Impedance Tomography. Excellent agreement between numerical simulations and experimental data was obtained, with the model-predicted anteroposterior ventilation profile achieving a Pearson correlation of 96% with the clinical reference data. Even when considering the regional ventilation within the entire transverse chest cross-section and across the entire dynamic ventilation range, an average correlation of more than 81% and an average root mean square error of less than 15% were achieved. The results of this first systematic validation study demonstrate the ability of computational models to provide clinically relevant information and thereby open the door for a truly patient-specific choice of ventilator settings on the basis of both individual anatomy and pathophysiology.
{"title":"Patient-specific prediction of regional lung mechanics in ARDS patients with physics-based models: A validation study","authors":"Maximilian Rixner, Maximilian Ludwig, Matthias Lindner, Inéz Frerichs, Armin Sablewski, Karl-Robert Wichmann, Max-Carl Wachter, Kei W. Müller, Dirk Schädler, Wolfgang A. Wall, Jonas Biehler, Tobias Becher","doi":"arxiv-2408.14607","DOIUrl":"https://doi.org/arxiv-2408.14607","url":null,"abstract":"The choice of lung protective ventilation settings for mechanical ventilation\u0000has a considerable impact on patient outcome, yet identifying optimal\u0000ventilatory settings for individual patients remains highly challenging due to\u0000the inherent inter- and intra-patient pathophysiological variability. In this\u0000validation study, we demonstrate that physics-based computational lung models\u0000tailored to individual patients can resolve this variability, allowing us to\u0000predict the otherwise unknown local state of the pathologically affected lung\u0000during mechanical ventilation. For seven ARDS patients undergoing invasive\u0000mechanical ventilation, physics-based, patient-specific lung models were\u0000created using chest CT scans and ventilatory data. By numerically resolving the\u0000interaction of the pathological lung with the airway pressure and flow imparted\u0000by the ventilator, we predict the time-dependent and heterogeneous local state\u0000of the lung for each patient and compare it against the regional ventilation\u0000obtained from bedside monitoring using Electrical Impedance Tomography.\u0000Excellent agreement between numerical simulations and experimental data was\u0000obtained, with the model-predicted anteroposterior ventilation profile\u0000achieving a Pearson correlation of 96% with the clinical reference data. Even\u0000when considering the regional ventilation within the entire transverse chest\u0000cross-section and across the entire dynamic ventilation range, an average\u0000correlation of more than 81% and an average root mean square error of less than\u000015% were achieved. The results of this first systematic validation study\u0000demonstrate the ability of computational models to provide clinically relevant\u0000information and thereby open the door for a truly patient-specific choice of\u0000ventilator settings on the basis of both individual anatomy and\u0000pathophysiology.","PeriodicalId":501378,"journal":{"name":"arXiv - PHYS - Medical Physics","volume":"390 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142176659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cervical cancer presents a significant global health challenge, necessitating advanced diagnostic and prognostic approaches for effective treatment. This paper investigates the potential of employing multi-modal medical imaging at various treatment stages to enhance cervical cancer treatment outcomes prediction. We show that among Gray Level Co-occurrence Matrix (GLCM) features, contrast emerges as the most effective texture feature regarding prediction accuracy. Integration of multi-modal imaging and texture analysis offers a promising avenue for personalized and targeted interventions, as well as more effective management of cervical cancer. Moreover, there is potential to reduce the number of time measurements and modalities in future cervical cancer treatment. This research contributes to advancing the field of precision diagnostics by leveraging the information embedded in noninvasive medical images, contributing to improving prognostication and optimizing therapeutic strategies for individuals diagnosed with cervical cancer.
{"title":"Multi-Modality and Temporal Analysis of Cervical Cancer Treatment Response","authors":"Haotian Feng, Emi Yoshida, Ke Sheng","doi":"arxiv-2408.13408","DOIUrl":"https://doi.org/arxiv-2408.13408","url":null,"abstract":"Cervical cancer presents a significant global health challenge, necessitating\u0000advanced diagnostic and prognostic approaches for effective treatment. This\u0000paper investigates the potential of employing multi-modal medical imaging at\u0000various treatment stages to enhance cervical cancer treatment outcomes\u0000prediction. We show that among Gray Level Co-occurrence Matrix (GLCM) features,\u0000contrast emerges as the most effective texture feature regarding prediction\u0000accuracy. Integration of multi-modal imaging and texture analysis offers a\u0000promising avenue for personalized and targeted interventions, as well as more\u0000effective management of cervical cancer. Moreover, there is potential to reduce\u0000the number of time measurements and modalities in future cervical cancer\u0000treatment. This research contributes to advancing the field of precision\u0000diagnostics by leveraging the information embedded in noninvasive medical\u0000images, contributing to improving prognostication and optimizing therapeutic\u0000strategies for individuals diagnosed with cervical cancer.","PeriodicalId":501378,"journal":{"name":"arXiv - PHYS - Medical Physics","volume":"40 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Till DreierLund University Department of Medical Radiation PhysicsExcillum AB, Robin KrügerLund University Department of Medical Radiation Physics, Gustaf BernströmLund University Department of Experimental Medical Science, Karin Tran-LundmarkLund University Department of Experimental Medical ScienceLund University Wallenberg Center for Molecular MedicineThe Pediatric Heart Center, Skåne University Hospital, Isabel GonçalvesCardiology, Skåne University Hospital, Martin BechLund University Department of Medical Radiation Physics
High-resolution x-ray tomography is a common technique for biomedical research using synchrotron sources. With advancements in laboratory x-ray sources, an increasing number of experiments can be performed in the lab. In this paper, the design, implementation, and verification of a laboratory setup for x-ray nano-computed tomography is presented using a nano-focus x-ray source and high geometric magnification not requiring any optical elements. Comparing a scintillator-based detector to a photon counting detector shows a clear benefit of using photon counting detectors for these applications, where the flux of the x-ray source is limited and samples have low contrast. Sample contrast is enhanced using propagation-based phase contrast. The resolution of the system is verified using 2D resolution charts and using Fourier Ring Correlation on reconstructed CT slices. Evaluating noise and contrast highlights the benefits of photon counting detectors and the contrast improvement through phase contrast. The implemented setup is capable of reaching sub-micron resolution and satisfying contrast in biological samples, like paraffin embedded tissue.
高分辨率 X 射线断层扫描是利用同步辐射源进行生物医学研究的常用技术。随着实验室 X 射线源的发展，越来越多的实验可以在实验室中进行。本文介绍了一种用于 X 射线纳米计算机断层扫描的实验室装置的设计、实施和验证，该装置使用纳米聚焦 X 射线源和高几何放大率，不需要任何光学元件。将基于闪烁体的探测器与光子计数探测器进行比较后发现，在 X 射线源流量有限且样品对比度较低的情况下，使用光子计数探测器在这些应用中具有明显的优势。利用基于传播的相位对比增强了样品对比度。使用二维分辨率图表和重建 CT 切片上的傅立叶环形相关性来验证系统的分辨率。对噪声和对比度的评估凸显了光子计数探测器和相位对比度提高对比度的优势。所实现的装置能够达到亚微米级分辨率，并能满足生物样本（如石蜡包埋组织）的对比度要求。
{"title":"Laboratory x-ray nano-computed tomography for biomedical research","authors":"Till DreierLund University Department of Medical Radiation PhysicsExcillum AB, Robin KrügerLund University Department of Medical Radiation Physics, Gustaf BernströmLund University Department of Experimental Medical Science, Karin Tran-LundmarkLund University Department of Experimental Medical ScienceLund University Wallenberg Center for Molecular MedicineThe Pediatric Heart Center, Skåne University Hospital, Isabel GonçalvesCardiology, Skåne University Hospital, Martin BechLund University Department of Medical Radiation Physics","doi":"arxiv-2408.12336","DOIUrl":"https://doi.org/arxiv-2408.12336","url":null,"abstract":"High-resolution x-ray tomography is a common technique for biomedical\u0000research using synchrotron sources. With advancements in laboratory x-ray\u0000sources, an increasing number of experiments can be performed in the lab. In\u0000this paper, the design, implementation, and verification of a laboratory setup\u0000for x-ray nano-computed tomography is presented using a nano-focus x-ray source\u0000and high geometric magnification not requiring any optical elements. Comparing\u0000a scintillator-based detector to a photon counting detector shows a clear\u0000benefit of using photon counting detectors for these applications, where the\u0000flux of the x-ray source is limited and samples have low contrast. Sample\u0000contrast is enhanced using propagation-based phase contrast. The resolution of\u0000the system is verified using 2D resolution charts and using Fourier Ring\u0000Correlation on reconstructed CT slices. Evaluating noise and contrast\u0000highlights the benefits of photon counting detectors and the contrast\u0000improvement through phase contrast. The implemented setup is capable of\u0000reaching sub-micron resolution and satisfying contrast in biological samples,\u0000like paraffin embedded tissue.","PeriodicalId":501378,"journal":{"name":"arXiv - PHYS - Medical Physics","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142176654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Parisa Salemi YolgunluUniversity of Bern, Jules BlomUniversity of Twente, Naiara Korta MartiartuUniversity of Bern, Michael JaegerUniversity of Bern
Computed ultrasound tomography in echo mode generates maps of tissue speed of sound (SoS) from the shift of echoes when detected under varying steering angles. It solves a linearized inverse problem that requires regularization to complement the echo shift data with a priori constraints. Spatial gradient regularization has been used to enforce smooth solutions, but SoS estimates were found to be biased depending on tissue layer geometry. Here, we propose to train a linear operator to minimize SoS errors on average over a large number of random tissue models that sample the distribution of geometries and SoS values expected in vivo. In an extensive simulation study on liver imaging, we demonstrate that biases are strongly reduced, with residual biases being the result of a partial non-linearity in the actual physical problem. This approach can either be applied directly to echo-shift data or to the SoS maps estimated with gradient regularization, where the former shows slightly better performance, but the latter is computationally more efficient. Experimental phantom results confirm the transferability of our results to real ultrasound data.
在回波模式下，超声计算机断层扫描可根据在不同转向角下检测到的回波位移生成组织声速（SoS）图。它解决的是一个线性化的逆问题，需要通过正则化将回波位移数据与先验约束条件相结合。空间梯度正则化已被用于执行平滑解，但 SoS 估计值会因组织层的几何形状而产生偏差。在此，我们建议训练一个线性算子，以平均最小化大量随机组织模型的 SoS 误差，这些组织模型采样了体内预期的几何分布和 SoS 值。在对肝脏成像进行的大量模拟研究中，我们证明偏差已大大减少，残余偏差是实际物理问题中部分非线性的结果。这种方法既可以直接应用于回波平移数据，也可以应用于梯度正则化估算的 SoS 地图，前者的性能略好，但后者的计算效率更高。实验结果证实了我们的方法可以应用于真实的超声数据。
{"title":"Learned Regularization for Quantitative Pulse-Echo Speed-of-Sound Imaging","authors":"Parisa Salemi YolgunluUniversity of Bern, Jules BlomUniversity of Twente, Naiara Korta MartiartuUniversity of Bern, Michael JaegerUniversity of Bern","doi":"arxiv-2408.11471","DOIUrl":"https://doi.org/arxiv-2408.11471","url":null,"abstract":"Computed ultrasound tomography in echo mode generates maps of tissue speed of\u0000sound (SoS) from the shift of echoes when detected under varying steering\u0000angles. It solves a linearized inverse problem that requires regularization to\u0000complement the echo shift data with a priori constraints. Spatial gradient\u0000regularization has been used to enforce smooth solutions, but SoS estimates\u0000were found to be biased depending on tissue layer geometry. Here, we propose to\u0000train a linear operator to minimize SoS errors on average over a large number\u0000of random tissue models that sample the distribution of geometries and SoS\u0000values expected in vivo. In an extensive simulation study on liver imaging, we\u0000demonstrate that biases are strongly reduced, with residual biases being the\u0000result of a partial non-linearity in the actual physical problem. This approach\u0000can either be applied directly to echo-shift data or to the SoS maps estimated\u0000with gradient regularization, where the former shows slightly better\u0000performance, but the latter is computationally more efficient. Experimental\u0000phantom results confirm the transferability of our results to real ultrasound\u0000data.","PeriodicalId":501378,"journal":{"name":"arXiv - PHYS - Medical Physics","volume":"59 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142176655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Quantitative magnetization transfer (MT) imaging enables non-invasive characterization of the macromolecular environment of tissues. However, recent work has highlighted that the quantification of MT parameters exhibits orientation dependence in ordered tissue structures, potentially confounding its clinical applications. Notably, in tissues with ordered structures, such as articular cartilage and myelin, the residual dipolar coupling (RDC) effect can arise owing to incomplete averaging of dipolar-dipolar interactions of water protons. In this study, we demonstrated the confounding effect of RDC on quantitative MT imaging in ordered tissues can be suppressed by using an emerging technique known as macromolecular proton fraction mapping based on spin-lock (MPF-SL). The off-resonance spin-lock pulse in MPF-SL could be designed to generate a strong effective spin-lock field to suppress RDC without violating the specific absorption rate and hardware limitations in clinical scans. Furthermore, removing the water signal in MPF-SL enabled the application of a strong effective spin-lock field without any confounding signal from direct water saturation. Our findings were experimentally validated using human knee specimens and healthy human cartilage. The results demonstrated that MPF-SL exhibits lower sensitivity to tissue orientation compared with R2, R1rho, and saturation-pulse-based MT imaging. Thus, MPF-SL could serve as a valuable orientation-independent technique for quantifying MPF.
{"title":"Orientation independent quantification of macromolecular proton fraction in tissues with suppression of residual dipolar coupling","authors":"Zijian Gao, Ziqiang Yu, Ziqin Zhou, Jian Hou, Baiyan Jiang, Michael Ong, Weitian Chen","doi":"arxiv-2408.09733","DOIUrl":"https://doi.org/arxiv-2408.09733","url":null,"abstract":"Quantitative magnetization transfer (MT) imaging enables non-invasive\u0000characterization of the macromolecular environment of tissues. However, recent\u0000work has highlighted that the quantification of MT parameters exhibits\u0000orientation dependence in ordered tissue structures, potentially confounding\u0000its clinical applications. Notably, in tissues with ordered structures, such as\u0000articular cartilage and myelin, the residual dipolar coupling (RDC) effect can\u0000arise owing to incomplete averaging of dipolar-dipolar interactions of water\u0000protons. In this study, we demonstrated the confounding effect of RDC on\u0000quantitative MT imaging in ordered tissues can be suppressed by using an\u0000emerging technique known as macromolecular proton fraction mapping based on\u0000spin-lock (MPF-SL). The off-resonance spin-lock pulse in MPF-SL could be\u0000designed to generate a strong effective spin-lock field to suppress RDC without\u0000violating the specific absorption rate and hardware limitations in clinical\u0000scans. Furthermore, removing the water signal in MPF-SL enabled the application\u0000of a strong effective spin-lock field without any confounding signal from\u0000direct water saturation. Our findings were experimentally validated using human\u0000knee specimens and healthy human cartilage. The results demonstrated that\u0000MPF-SL exhibits lower sensitivity to tissue orientation compared with R2,\u0000R1rho, and saturation-pulse-based MT imaging. Thus, MPF-SL could serve as a\u0000valuable orientation-independent technique for quantifying MPF.","PeriodicalId":501378,"journal":{"name":"arXiv - PHYS - Medical Physics","volume":"2016 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142176658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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