检索结果-内蒙古大学图书馆

Comment on "Transconvolution and the virtual positron emission tomograph: A new method for cross calibration in quantitative PET/CT imaging" [Med. Phys. 40, 062503 (15pp.) (2013)]

引用

MEDICAL PHYSICS 2013年第11期40卷 117101页

作者： Hofheinz, F. van den Hoff, J. Helmholtz Zentrum Dresden Rossendorf Inst Radiopharmaceut Canc Res PET Ctr D-01314 Dresden Germany Tech 10 Univ Dresden Univ Hosp Carl Gustav Carus Dept Nucl Med D-01307 Dresden Germany

来源：评论

学校读者我要写书评

暂无评论

Comment on "It is not appropriate to 'deform' dose along with deformable image registration in adaptive radiotherapy" [Med. Phys. 39, 6531-6533 (2012)]

引用

MEDICAL PHYSICS 2013年第1期40卷 017101页

作者： Taylor, M. L. Yeo, U. J. Kron, T. Supple, J. Siva, S. Pham, D. Franich, R. D. RMIT Univ Sch Appl Sci Melbourne Vic 3000 Australia RMIT Univ Hlth Innovat Res Inst Melbourne Vic 3000 Australia Peter MacCallum Canc Ctr Radiat Therapy Serv Melbourne Vic 3002 Australia

来源：评论

学校读者我要写书评

暂无评论

Visibility of microcalcification clusters and masses in breast tomosynthesis image volumes and digital mammography: A 4AFC human observer study

引用

MEDICAL PHYSICS 2012年第5期39卷 2431-2437页

作者： Timberg, P. Bath, M. Andersson, I. Mattsson, S. Tingberg, A. Ruschin, M. Lund Univ Skane Univ Hosp Dept Clin Sci Malmo SE-20502 Malmo Sweden Sahlgrens Univ Hosp Dept Med Phys & Biomed Engn SE-41345 Gothenburg Sweden Univ Gothenburg Sahlgrenska Acad Dept Radiat Phys Inst Clin Sci SE-41345 Gothenburg Sweden Skane Univ Hosp Dept Radiat Phys SE-20502 Malmo Sweden Princess Margaret Hosp Univ Hlth Network Radiat Med Program Toronto ON M5G 2M9 Canada

Purpose: To investigate the visibility of simulated lesions in digital breast tomosynthesis (BT) image volumes compared with 2D digital mammography (DM). Methods: Simulated lesions (masses and microcalcifications) were added to images of the same women acquired on a DM system (Mammomat Novation, Siemens) and a BT prototype. The same beam quality was used for the DM and BT acquisitions. The total absorbed dose resulting from a 25-projection BT acquisition and reconstruction (BT25) was approximately twice that of a single DM view. By excluding every other projection image from the reconstruction (BT13), approximately the same dose as in DM was effected. Simulated microcalcifications were digitally added with varying contrast to the DM and BT images. Simulated masses with 8 mm diameter were also added to BT images. A series of 4-alternative forced choice (4AFC) human observer experiments were conducted. Four medical physicists participated in all experiments, each consisting of 60 trials per experimental condition. The observers interpreted the BT image volumes in cine-mode at a fixed image sequence speed. The required threshold contrast (S-t) to achieve a detectability index (d') of 2.5 (i.e., 92.5% correct decisions) was determined. Results: The St for mass detection in DM was approximately a factor of 2 higher than required in BT indicating that the detection of masses was improved under BT conditions compared to DM. St for microcalcification detection was higher for BT than for DM at both BT dose levels (BT25 and BT13), with a statistically significant difference in St between DM and BT13. These results indicate a dose-dependent decrease in detection performance in BT for detection of microcalcifications. Conclusions: In agreement with previous investigations, masses of size 8 mm can be detected with less contrast in BT than in DM indicating improved detection performance for BT. However, for the investigated microcalcifications, the results of this study indicate

关键词： Mammography Reconstruction Contrast biological tissues dosimetry image reconstruction image sequences mammography medical image processing Digital computing or data processing equipment or methods, specially adapted for specific applications image data processing or generation, in general Medical imaging image sensors image detection systems Medical image reconstruction Medical image contrast image reconstruction Visibility Dosimetry Digital mammography Medical image noise

来源：评论

学校读者我要写书评

暂无评论

Predicting target vessel location on robot-assisted coronary artery bypass graft using CT to ultrasound registration

引用

MEDICAL PHYSICS 2012年第3期39卷 1579-1587页

作者： Cho, Daniel S. Linte, Cristian Chen, Elvis C. S. Bainbridge, Daniel Wedlake, Chris Moore, John Barron, John Patel, Rajni Peters, Terry Univ Western Ontario Robarts Res Inst Imaging Res Labs London ON N6A 5K8 Canada Univ Western Ontario Biomed Engn Grad Program London ON N6A 5K8 Canada Mayo Clin Robarts Res Inst Imaging Res Labs Rochester MN 55905 USA Canadian Surg Technol & Adv Robot London ON N6A 5A5 Canada Univ Western Ontario Dept Comp Sci London ON N6A 5B7 Canada

Purpose: Although robot-assisted coronary artery bypass grafting (RA-CABG) has gained more acceptance worldwide, its success still depends on the surgeon's experience and expertise, and the conversion rate to full sternotomy is in the order of 15%-25%. One of the reasons for conversion is poor preoperative planning, which is based solely on pre-operative computed tomography (CT) images. In this paper, the authors propose a technique to estimate the global peri-operative displacement of the heart and to predict the intra-operative target vessel location, validated via both an in vitro and a clinical study. Methods: As the peri-operative heart migration during RA-CABG has never been reported in the literatures, a simple in vitro validation study was conducted using a heart phantom. To mimic the clinical workflow, a pre-operative CT as well as peri-operative ultrasound images at three different stages in the procedure (Stage(0)-following intubation;Stage(1)-following lung deflation;and Stage(2)-following thoracic insufflation) were acquired during the experiment. Following image acquisition, a rigid-body registration using iterative closest point algorithm with the robust estimator was employed to map the pre-operative stage to each of the peri-operative ones, to estimate the heart migration and predict the peri-operative target vessel location. Moreover, a clinical validation of this technique was conducted using offline patient data, where a Monte Carlo simulation was used to overcome the limitations arising due to the invisibility of the target vessel in the peri-operative ultrasound images. Results: For the in vitro study, the computed target registration error (TRE) at Stage(0), Stage(1), and Stage(2) was 2.1, 3.3, and 2.6 mm, respectively. According to the offline clinical validation study, the maximum TRE at the left anterior descending (LAD) coronary artery was 4.1 mm at Stage(0), 5.1 mm at Stage(1), and 3.4 mm at Stage(2). Conclusions: The authors proposed a m

关键词： Robotics X-ray imaging Monte Carlo simulations Registration Computed tomography Ultrasonographic imaging biomedical ultrasonics blood vessels cardiology computerised tomography estimation theory image registration lung medical image processing medical robotics Monte Carlo methods phantoms planning ultrasonic imaging Computerised tomographs Diagnosis using ultrasonic, sonic or infrasonic waves Digital computing or data processing equipment or methods, specially adapted for specific applications image data processing or generation, in general Medical imaging Computed tomography Heart Ultrasonography Multivariate analysis Medical image segmentation Lungs Monte Carlo methods Robotics Vascular system

来源：评论

学校读者我要写书评

暂无评论

A computerized scheme for lung nodule detection in multiprojection chest radiography

引用

MEDICAL PHYSICS 2012年第4期39卷 2001-2012页

作者： Guo, Wei Li, Qiang Boyce, Sarah J. McAdams, H. Page Shiraishi, Junji Doi, Kunio Samei, Ehsan Duke Univ Med Ctr Carl E Ravin Adv Imaging Labs Dept Radiol Durham NC 27705 USA Northeastern Univ Coll Informat Sci & Engn Shenyang 110004 Liaoning Peoples R China Univ N Carolina Dept Biomed Engn Chapel Hill NC 27599 USA Kumamoto Univ Fac Life Sci Kumamoto 9620976 Japan Univ Chicago Dept Radiol Kurt Rossmann Labs Radiol Image Res Chicago IL 60637 USA Duke Univ Dept Phys Durham NC 27705 USA Duke Univ Dept Biomed Engn Durham NC 27705 USA Duke Univ Dept Elect & Comp Engn Durham NC 27705 USA Duke Univ Dept Med Phys Durham NC 27705 USA

Purpose: Our previous study indicated that multiprojection chest radiography could significantly improve radiologists' performance for lung nodule detection in clinical practice. In this study, the authors further verify that multiprojection chest radiography can greatly improve the performance of a computer-aided diagnostic (CAD) scheme. Methods: Our database consisted of 59 subjects, including 43 subjects with 45 nodules and 16 subjects without nodules. The 45 nodules included 7 real and 38 simulated ones. The authors developed a conventional CAD scheme and a new fusion CAD scheme to detect lung nodules. The conventional CAD scheme consisted of four steps for (1) identification of initial nodule candidates inside lungs, (2) nodule candidate segmentation based on dynamic programming, (3) extraction of 33 features from nodule candidates, and (4) false positive reduction using a piecewise linear classifier. The conventional CAD scheme processed each of the three projection images of a subject independently and discarded the correlation information between the three images. The fusion CAD scheme included the four steps in the conventional CAD scheme and two additional steps for (5) registration of all candidates in the three images of a subject, and (6) integration of correlation information between the registered candidates in the three images. The integration step retained all candidates detected at least twice in the three images of a subject and removed those detected only once in the three images as false positives. A leave-one-subject-out testing method was used for evaluation of the performance levels of the two CAD schemes. Results: At the sensitivities of 70%, 65%, and 60%, our conventional CAD scheme reported 14.7, 11.3, and 8.6 false positives per image, respectively, whereas our fusion CAD scheme reported 3.9, 1.9, and 1.2 false positives per image, and 5.5, 2.8, and 1.7 false positives per patient, respectively. The low performance of the conventional CAD

关键词： Radiography Multislice Segmentation Registration cancer computerised tomography diagnostic radiography dynamic programming feature extraction image registration image segmentation lung medical image processing Computerised tomographs Digital computing or data processing equipment or methods, specially adapted for specific applications image data processing or generation, in general Medical imaging Radiography Lungs Information integration Cancer Computer aided diagnosis Medical X-ray imaging image sensors Computed tomography Dosimetry

来源：评论

学校读者我要写书评

暂无评论

Toward a practical template-based approach to semiquantitative SPECT myocardial perfusion imaging

引用

MEDICAL PHYSICS 2012年第3期39卷 1374-1385页

作者： Hughes, Tyler Celler, Anna Univ British Columbia Dept Phys & Astron Vancouver BC V5Z 1M9 Canada Univ British Columbia Dept Radiol Vancouver BC Canada

Purpose: Our template-based quantitative perfusion single photon emission computed tomography (SPECT) method (T-QPS) performs semiquantitative analysis for myocardial perfusion imaging (MPI) without the use of normal databases. However, in its current form, T-QPS requires extensive calculations, which limits its clinical application. In the interest of clinical feasibility, the authors examine the trade-off between accuracy and processing time as the method is simplified. Methods: The T-QPS method uses the reconstructed SPECT image of the patient to create a 3D digital template of his/her healthy heart. This template is then projected, reconstructed, and sampled into the bulls-eye map domain. A ratio of the patient and template images produces a final corrected image in which a threshold is applied to identify perfusion defects. In principle, the template should be constructed with the heart and all extracardiac activity, and the projection step should include primary and scatter components;however, this leads to lengthy calculations. In an attempt to shorten the processing time, the authors analyzed the performance of four template (T) generation methods: TP-HRT, TPS-HRT, TP-HRTBKG, and TPS-HRTBKG, where P and S represent primary and scattered photons included in the projection step, respectively;and HRT and HRTBKG represent template constructed with the heart only and the heart with background activity, respectively. Forty-eight thorax phantoms and 21 randomly selected patient studies were analyzed using each approach. All studies used GE's Infinia Hawkeye SPECT/CT system and followed a standard cardiac acquisition protocol. Results: Approximate processing times for the TP-HRT, TPS-HRT, TP-HRTBKG, and TPS-HRTBKG methods were less than a minute, 2-3 h, less than a minute and 3-4 h, respectively. In both the simulation and patient studies, a significant reduction in the quality of perfusion defect definition was exhibited by the TP-HRT method relative to the other t

关键词： Single photon emission computed tomography (SPECT) Reconstruction cardiology image reconstruction medical image processing single photon emission computed tomography Digital computing or data processing equipment or methods, specially adapted for specific applications image data processing or generation, in general Medical imaging Heart Single photon emission computed tomography Photons Medical image artifacts Computer software Medical image reconstruction Photon scattering Liver databases

来源：评论

学校读者我要写书评

暂无评论

Accelerated Barrier Optimization Compressed Sensing (ABOCS) Reconstruction for Cone-Beam CT

引用

MEDICAL PHYSICS 2012年第6期39卷 3892-3893页

作者： Niu, T. Zhu, L. Georgia Inst Tech Atlanta GA USA

OBJECTIVE:Recent advances in compressed sensing (CS) enable accurate CT image reconstruction from highly undersampled and noisy projection measurements, due to the sparsifiable feature of most CT images using total variation (TV). These novel reconstruction methods have demonstrated advantages in clinical applications where radiation dose reduction is critical, such as onboard cone-beam CT (CBCT) imaging in radiation therapy. The image reconstruction using CS is formulated as either a constrained problem to minimize the TV objective within a small and fixed data fidelity error, or an unconstrained problem to minimize the data fidelity error with TV regularization. However, the conventional solutions to the above two formulations are either computationally inefficient or involved with inconsistent regularization parameter tuning, which significantly limit the clinical use of CS-based iterative reconstruction. In this paper, we propose an optimization algorithm for CS reconstruction which overcomes the above two drawbacks.;METHODS:The data fidelity tolerance of CS reconstruction can be well estimated based on the measured data, as most of the projection errors are from Poisson noise after effective data correction for scatter and beam-hardening effects. We therefore adopt the TV optimization framework with a data fidelity constraint. To accelerate the convergence, we first convert such a constrained optimization using a logarithmic barrier method into a form similar to that of the conventional TV regularization based reconstruction but with an automatically adjusted penalty weight. The problem is then solved efficiently by gradient projection with an adaptive Barzilai-Borwein step-size selection scheme. The proposed algorithm is referred to as accelerated barrier optimization for CS (ABOCS), and evaluated using both digital and physical phantom studies.;RESULTS:ABOCS directly estimates the data fidelity tolerance from the raw projection data. Therefore, as demonstrate

关键词： Computed tomography Numerical optimization computerised tomography convergence image reconstruction mathematics computing medical image processing noise optimisation phantoms radiation therapy iterative reconstruction compressed sensing total variation logarithmic barrier cone-beam CT Computerised tomographs Radiation therapy Complex mathematical operations Digital computing or data processing equipment or methods, specially adapted for specific applications image data processing or generation, in general Medical imaging Medical image reconstruction image reconstruction Medical image noise Cone beam computed tomography image sensors Computed tomography Poisson's equation Medical image quality Optimization

来源：评论

学校读者我要写书评

暂无评论

Technical Note: Suppression of artifacts arising from simultaneous cone-beam imaging and RF transponder tracking in prostate radiotherapy

引用

MEDICAL PHYSICS 2012年第3期39卷 1646-1649页

作者： Poludniowski, Gavin Webb, Steve Evans, Philip M. Inst Canc Res Joint Dept Phys Div Radiotherapy & Imaging Sutton SM2 5PT Surrey England Royal Marsden NHS Fdn Trust Sutton SM2 5PT Surrey England

Purpose: Artifacts in treatment-room cone-beam reconstructions have been observed at the authors' center when cone-beam acquisition is simultaneous with radio frequency (RF) transponder tracking using the Calypso 4D system (Calypso Medical, Seattle, WA). These artifacts manifest as CT-number modulations and increased CT-noise. The authors present a method for the suppression of the artifacts. Methods: The authors propose a three-stage postprocessing technique that can be applied to image volumes previously reconstructed by a cone-beam system. The stages are (1) segmentation of voxels into air, soft-tissue, and bone;(2) application of a 2D spatial-filter in the axial plane to the soft-tissue voxels;and (3) normalization to remove streaking along the axial-direction. The algorithm was tested on patient data acquired with Synergy XVI cone-beam CT systems (Elekta, Crawley, United Kingdom). Results: The computational demands of the suggested correction are small, taking less than 15 s per cone-beam reconstruction on a desktop PC. For a moderate loss of spatial-resolution, the artifacts are strongly suppressed and low-contrast visibility is improved. Conclusions: The correction technique proposed is fast and effective in removing the artifacts caused by simultaneous cone-beam imaging and RF-transponder tracking. VC 2012 American Association of Physicists in Medicine. [http://***/10.1118/1.3689809]

关键词： Computed tomography Computed radiography Artifacts and distortion Reconstruction Segmentation biological organs bone cancer computerised tomography image reconstruction image segmentation medical image processing radiation therapy Computerised tomographs Radiation therapy Digital computing or data processing equipment or methods, specially adapted for specific applications image data processing or generation, in general Medical imaging Cone beam computed tomography Medical image reconstruction Medical image artifacts Visibility Computed tomography Radiation therapy Medical X-ray imaging Target tracking Tracking devices

来源：评论

学校读者我要写书评

暂无评论

Reply to "Comment on the 'Report of AAPM TG 204: Size-specific dose estimates (SSDE) in pediatric and adult body CT examinations'" [AAPM Report 204, 2011]

引用

MEDICAL PHYSICS 2012年第7期39卷 4615-4616页

作者： Boone, John M. UC Davis Med Ctr Dept Radiol Sacramento CA 95817 USA

来源：评论

学校读者我要写书评

暂无评论

PET-based GTV definition is the future of radiotherapy treatment planning

引用

MEDICAL PHYSICS 2012年第10期39卷 5791-5794页

作者： Ahmad, Salahuddin Devic, Slobodan Orton, Colin G. Univ Oklahoma Hlth Sci Ctr Dept Radiat Oncol Oklahoma City OK 73104 USA McGill Univ Jewish Gen Hosp Montreal PQ H3T 1E2 Canada

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：