Abstract：
:The hybrid algorithms developed recently for the reconstruction of fan-beam images possess computational and noise properties superior to those of the fan-beam filtered backprojection (FFBP) algorithm. However, the hybrid algorithms cannot be applied directly to a halfscan fan-beam sinogram because they require knowledge of a fullscan fan-beam sinogram. In this work, we developed halfscan-hybrid algorithms for image reconstruction in halfscan computed tomography (CT). Numerical evaluation indicates that the proposed halfscan-hybrid algorithms are computationally more efficient than are the widely used halfscan-FFBP algorithms. Also, the results of quantitative studies demonstrated clearly that the noise levels in images reconstructed by use of the halfscan-hybrid algorithm are generally lower and spatially more uniform than are those in images reconstructed by use of the halfscan-FFBP algorithm. Such reduced and uniform image noise levels may be translated into improvement of the accuracy and precision of lesion detection and parameter estimation in noisy CT images without increasing the radiation dose to the patient. Therefore, the halfscan-hybrid algorithms may have significant implication for image reconstruction in conventional and helical CT.
journal_name
Med Physjournal_title
Medical physicsauthors
Pan Xdoi
10.1118/1.1288239subject
Has Abstractpub_date
2000-09-01 00:00:00pages
2031-6issue
9eissn
0094-2405issn
2473-4209journal_volume
27pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract：PURPOSE:To evaluate the accuracy of skin dose determination for composite multibeam 3D conformal radiation therapy (3DCRT) and intensity modulated radiation therapy (IMRT) treatments using optically stimulated luminescent dosimeters (OSLDs) and Eclipse treatment planning system. METHODS:Surface doses measured by OSLDs...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4890795
更新日期：2014-08-01 00:00:00
abstract：PURPOSE:The treatment of thoracic cancer using external beam radiation requires an optimal selection of the radiation beam directions to ensure effective coverage of the target volume and to avoid unnecessary treatment of normal healthy tissues. Intensity modulated radiation therapy (IMRT) planning is a lengthy process...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4908000
更新日期：2015-04-01 00:00:00
abstract：PURPOSE:To study the impact of target geometrical and linac operational parameters, such as target material and thickness, electron beam size, repetition rate, and mean current on the ability of the radiotherapy treatment head to deliver high-dose-rate x-ray irradiation in the context of novel linear accelerators capab...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12615
更新日期：2017-12-01 00:00:00
abstract：:Setting up and maintaining video display monitors properly will help to reduce display variation and improve overall presentation of the radiological image. Display monitor gray-scale characteristics were examined using the SMPTE test pattern. This test pattern may be used as a standard for adjusting brightness and co...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596846
更新日期：1992-05-01 00:00:00
abstract：PURPOSE:In this article, the authors studied the feasibility of estimating regional mechanical properties in cerebral aneurysms, integrating information extracted from imaging and physiological data with generic computational models of the arterial wall behavior. METHODS:A data assimilation framework was developed to ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3355933
更新日期：2010-04-01 00:00:00
abstract：:The main purpose of this work is to demonstrate a practical means of determining the leaf transmission and scatter characteristics of a multileaf collimator (MLC) pertinent to the commissioning of dynamic intensity modulated radiotherapy, especially for the sweeping window technique. The data are necessary for the con...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1312190
更新日期：2000-10-01 00:00:00
abstract：PURPOSE:To present a noninvasive technique for directly measuring the CT bow-tie filter attenuation with a linear array x-ray detector. METHODS:A scintillator based x-ray detector of 384 pixels, 307 mm active length, and fast data acquisition (model X-Scan 0.8c4-307, Detection Technology, FI-91100 Ii, Finland) was use...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4932364
更新日期：2015-11-01 00:00:00
abstract：PURPOSE:The image registration literature comprises many methods for 2D-3D registration for which accuracy has been established in a variety of applications. However, clinical application is limited by a small capture range. Initial offsets outside the capture range of a registration method will not converge to a succe...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3366252
更新日期：2010-04-01 00:00:00
abstract：:In this study, we present an algorithm for three-dimensional (3-D) dose reconstruction using portal images obtained with an electronic portal imaging device (EPID). For this purpose an algorithm for 2-D dose reconstruction, which was previously developed in our institution, was adapted. The external contour of the pat...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1589496
更新日期：2003-09-01 00:00:00
abstract：PURPOSE:To find an upper bound on the maximum dose reduction possible for any reconstruction algorithm, analytic or iterative, that result from the inclusion of the data statistics. The authors do not analyze noise reduction possible from prior knowledge or assumptions about the object. METHODS:The authors examined th...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4941954
更新日期：2016-03-01 00:00:00
abstract：:In patients with lymphoma, identification and quantification of the tumor extent on serial CT examinations is critical for assessing tumor response to therapy. In this paper, we present a computer method to automatically match and segment lymphomas in follow-up CT images. The method requires that target lymph nodes in...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2404617
更新日期：2007-01-01 00:00:00
abstract：PURPOSE:Cone-beam computed tomography (CBCT) is an increasingly utilized imaging modality for the diagnosis and treatment planning of the patients with craniomaxillofacial (CMF) deformities. Accurate segmentation of CBCT image is an essential step to generate three-dimensional (3D) models for the diagnosis and treatmen...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4868455
更新日期：2014-04-01 00:00:00
abstract：:Image intensifier-television-video digitizer (IITVD) systems are commonly used for digital planar image acquisition in radiology. However, the well-known distortions inherent in these systems limit their utility in research and in some clinical applications where quantitatively correct images are required. Software co...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596718
更新日期：1991-03-01 00:00:00
abstract：:The purpose of this study was to investigate if interfraction and intrafraction motion in free-breathing and gated lung IMRT can lead to systematic dose differences between 3DCT and 4DCT. Dosimetric effects were studied considering the breathing pattern of three patients monitored during the course of their treatment ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2821704
更新日期：2008-01-01 00:00:00
abstract：PURPOSE:This paper describes the low-kV spectral optimization of dual-energy CT (DECT) equipped with high-kV tin filtration for the quantitative acquisition of electron density information, which is essential for treatment planning in radiotherapy. In addition, an analytical DECT image simulation was preliminarily perf...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3584200
更新日期：2011-06-01 00:00:00
abstract：:Quantitative evaluation of cardiac image data obtained using multidetector row computed tomography (CT) is compromised by partial scan reconstructions, which improve the temporal resolution but significantly increase image-to-image CT number variations for a fixed region of interest compared to full reconstruction ima...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2805476
更新日期：2007-12-01 00:00:00
abstract：:Our purpose in this work is to demonstrate that the efficiency of dose-rate computations in 125I brachytherapy, using multigroup discrete ordinates radiation transport simulations, can be significantly enhanced using broad energy group cross sections without a loss of accuracy. To this end, the DANTSYS multigroup disc...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1429238
更新日期：2002-02-01 00:00:00
abstract：PURPOSE:Both spatial and biological information are necessary in order to perform true optimization of a treatment plan and for predicting clinical outcome. The goal of this work is to develop an enhanced treatment plan evaluation tool which incorporates biological parameters and retains spatial dose information. METH...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3497152
更新日期：2010-11-01 00:00:00
abstract：PURPOSE:Theoretical models of the detective quantum efficiency (DQE) of x-ray detectors are an important step in new detector development by providing an understanding of performance limitations and benchmarks. Previous cascaded-systems analysis (CSA) models accounted for photoelectric interactions only. This paper des...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4794495
更新日期：2013-04-01 00:00:00
abstract：:The purpose of this study was to investigate the effect of z overscanning on eye lens dose and effective dose received by pediatric patients undergoing head CT examinations. A pediatric patient study was carried out to obtain the exposure parameters and data regarding the eye lens position with respect to imaged volum...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2207212
更新日期：2006-07-01 00:00:00
abstract：PURPOSE:The simultaneous measurement of PET and magnetic resonance imaging (MRI) is an emerging field for molecular imaging research. Although optical fiber based PET∕MRI systems have advantages on less interference between PET and MRI, there is a drawback in reducing the scintillation light due to the fiber. To reduce...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4757911
更新日期：2012-11-01 00:00:00
abstract：:The use of electronic portal imaging devices (EPIDs) is a promising method for the dosimetric verification of external beam, megavoltage radiation therapy-both pretreatment and in vivo. In this study, a previously developed EPID back-projection algorithm was modified for IMRT techniques and applied to an amorphous sil...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2147744
更新日期：2006-02-01 00:00:00
abstract：PURPOSE:New preclinical image-guided irradiators and treatment planning systems represent a huge progress in radiobiology. Nevertheless, quality control of preclinical treatments is not as advanced as in clinical radiotherapy and in vivo dosimetry is less developed. In this study, we evaluate the use of a scintillating...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.13903
更新日期：2020-01-01 00:00:00
abstract：PURPOSE:The possible clinical applications which can be performed using a newly developed detector depend on the detector's characteristic performance in a number of metrics including the dynamic range, resolution, uniformity, and stability. The authors have evaluated a prototype energy resolved fast photon counting x-...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4892174
更新日期：2014-09-01 00:00:00
abstract：PURPOSE:Breast density is a significant breast cancer risk factor. Although various methods are used to estimate breast density, there is no standard measurement for this important factor. The authors are developing a breast density standardization method for use in full field digital mammography (FFDM). The approach c...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3250842
更新日期：2009-12-01 00:00:00
abstract：:A Monte Carlo study of dosimetry for eye plaque brachytherapy is performed. BrachyDose, an EGSnrc user code which makes use of Yegin's multi-geometry package, is used to fully model I125 (model 6711) and Pd103 (model 200) brachytherapy seeds and the standardized plaques of the Collaborative Ocular Melanoma Study (COMS...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3002412
更新日期：2008-12-01 00:00:00
abstract：PURPOSE:Avoiding measurement variability from 18 F phantom preparation by using 68 Ge/68 Ga phantoms for the determination of 18 F recovery curves (RC) in clinical quality assurance measurements and for PET/CT site qualification in multicentre clinical trials. METHODS:RCs were obtained from PET/CT measurements of seve...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12330
更新日期：2017-07-01 00:00:00
abstract：:The physical characteristics of a clinical charge coupled device (CCD)-based imager (Senovision, GE Medical Systems, Milwaukee, WI) for small-field digital mammography have been investigated. The imager employs a MinR 2000 (Eastman Kodak Company, Rochester, NY) scintillator coupled by a 1:1 optical fiber to a front-il...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1286720
更新日期：2000-08-01 00:00:00
abstract：:Quantitation of planar radionuclide images is hampered by structures containing radioactivity which overlie or underlie the organ of interest. The introduction of single photon emission computerized tomography (SPECT) overcame this problem to a large extent and enhanced the contrast of the images. Attenuation of photo...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596684
更新日期：1991-05-01 00:00:00
abstract：:An overall practical dosimetric study of a 10-MV photon beam produced by a Varian Clinac-18 linear accelerator is presented. In particular measurements were made to provide data which could be utilized in computerized dosage calculations using the concept of dividing the radiation beam into primary and scatter compone...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.594311
更新日期：1977-03-01 00:00:00
