Abstract：
:The method of magnetic resonance imaging (MRI) was an extension of nuclear magnetic resonance (NMR) spectroscopy that was enabled by computational systems capable of performing the Fast Fourier Transform. Initially, a diverse group of methods were proposed for producing images with NMR, with the multi-slice spin-warp spin echo MRI method winning out as the first clinically useful approach. Immediately radiologists were impressed in the soft tissue contrast seen in MR images and the great flexibility with which image contrast could be manipulated. Over the years, advances in both hardware and the implementation of new pulse sequences of increasing complexity led to the increasing utility of MRI. The great success of MRI research contributed to the awarding of both the Nobel Prize in Chemistry for Richard Ernst in 1991 and the Nobel Prize in Physiology or Medicine for Lauterbur and Mansfield in 2003. The evolution of the modality produced increasing speed of acquisition, finer spatial resolution and an expanding range of clinical applications. Technological advances included improvements in gradient coils, superconducting magnets, phased array radiofrequency coils, and partially parallel image reconstruction algorithms. The wide range of applications developed include MR angiography, BOLD contrast functional MRI, and diffusion-weighted MRI. This section of the symposium will conclude with a look a current developments and where they are likely to take the field into the future.
journal_name
Med Physjournal_title
Medical physicsauthors
Clarke Gdoi
10.1118/1.4736176subject
Has Abstractpub_date
2012-06-01 00:00:00pages
3964issue
6Part28eissn
0094-2405issn
2473-4209journal_volume
39pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract：:Computed tomography is sensitive to changes in the imaged distribution during acquisition of the projection data. Previous investigations have emphasized discrete or discontinuous changes in the imaged object. Recent advances have motivated our investigation of object time-dependence characterized by a continuous func...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.594458
更新日期：1978-11-01 00:00:00
abstract：PURPOSE:In this study, we evaluated the degree of consistency between size metrics obtained from PEM and MRI to determine the intrinsic effectiveness of a multimodality approach using these two systems for breast imaging. METHODS:Under an IRB-approved protocol, 42 cases were considered (16 patients with 28 lesions), e...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4735979
更新日期：2012-06-01 00:00:00
abstract：PURPOSE:To commission and benchmark a vendor-supplied (Varian Medical Systems) Monte Carlo phase-space data for the 6 MV flattening filter free (FFF) energy mode on a TrueBeam linear accelerator for the purpose of quality assurance of clinical volumetric modulated arc therapy (VMAT) treatment plans. A method for render...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4773883
更新日期：2013-02-01 00:00:00
abstract：PURPOSE:The authors' objective was to compare internal dose estimates obtained using the Organ Level Dose Assessment with Exponential Modeling (OLINDA/EXM) software, the voxel S value technique, and Monte Carlo simulation. Monte Carlo dose estimates were used as the reference standard to assess the impact of patient-sp...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4892606
更新日期：2014-09-01 00:00:00
abstract：:The fast imaging method named skipped phase encoding and edge deghosting (SPEED) has been demonstrated to reduce scan time considerably with typical magnetic resonance imaging data. In this work, SPEED is simplified with improved efficiency to accelerate the scan of sparse objects; we refer to this method as S-SPEED. ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2750966
更新日期：2007-08-01 00:00:00
abstract：:Molecular imaging is the direct or indirect noninvasive monitoring and recording of the spatial and temporal distribution of in vivo molecular, genetic, and/or cellular processes for biochemical, biological, diagnostic, or therapeutic applications. Molecular images that indicate the presence of malignancy can be acqui...
journal_title：Medical physics
pub_type： 杂志文章,评审
doi：10.1118/1.4819818
更新日期：2013-10-01 00:00:00
abstract：PURPOSE:To improve the efficiency of atlas-based segmentation without compromising accuracy, and to demonstrate the validity of the proposed method on MRI-based prostate segmentation application. METHODS:Accurate and efficient automatic structure segmentation is an important task in medical image processing. Atlas-bas...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4867855
更新日期：2014-04-01 00:00:00
abstract：PURPOSE:The authors have previously reported the advantages of high-sensitivity single-photon emission computed tomography (SPECT) systems for imaging structures located deep inside the brain. DaTscan (Isoflupane I-123) is a dopamine transporter (DaT) imaging agent that has shown potential for early detection of Parkin...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4794488
更新日期：2013-04-01 00:00:00
abstract：PURPOSE:Radiation treatments are trending toward delivering higher doses per fraction under stereotactic radiosurgery and hypofractionated treatment regimens. There is a need for accurate 3D in vivo patient dose verification using electronic portal imaging device (EPID) measurements. This work presents a model-based te...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4935199
更新日期：2015-12-01 00:00:00
abstract：:The ability of Leksell GammaPlan to perform stereotactic space localizations with image sets where there is misalignment of the patient's head (stereotactic frame and fiducial apparatus) relative to the computed tomography (CT) scanner coordinate system was studied. Misalignment is sometimes necessary for patient comf...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2179751
更新日期：2006-04-01 00:00:00
abstract：:The image artifacts characteristic of a scanning chest radiographic system are reviewed. The technique employs a pulsed beam of radiation swept in an overlapping raster pattern that can result in severe ripple and scan line artifacts with improper scanning parameters. A one-dimensional treatment of the scanner geometr...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.595492
更新日期：1984-03-01 00:00:00
abstract：:Generating an optimized radiation treatment plan requires understanding the factors affecting tumour control. Mathematical models of tumour dynamics may help in future studies of factors predicting tumor sensitivity to radiotherapy. In this study, a time-dependent differential model, incorporating biological cancer ma...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2965923
更新日期：2008-07-01 00:00:00
abstract：PURPOSE:The need for four-dimensional (4D) treatment planning becomes indispensable when it comes to radiation therapy for moving tumors in the thoracic and abdominal regions. The primary purpose of this study is to combine the actual breathing trace during each individual treatment fraction with the Linac's log file i...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.13579
更新日期：2019-07-01 00:00:00
abstract：:The intensity of Compton scattered photons is directly proportional to the electron density of a substance; therefore it is possible to detect changes in electron density by this noninvasive method. The source-detector geometry has been varied to study the effects of geometry on the calculated electron density values,...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.595730
更新日期：1985-01-01 00:00:00
abstract：PURPOSE:To develop and investigate a continuous path optimization methodology to traverse prescribed non-coplanar IMRT beams with variant SADs, by orchestrating the couch and gantry movement with zero-collision, minimal patient motion consequence and machine travel time. METHODS:We convert the given collision zone def...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4735996
更新日期：2012-06-01 00:00:00
abstract：PURPOSE:The automated correct segmentation of left and right lungs is a nontrivial problem, because the tissue layer between both lungs can be quite thin. In the case of lung segmentation with left and right lung models, overlapping segmentations can occur. In this paper, the authors address this issue and propose a so...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4894817
更新日期：2014-10-01 00:00:00
abstract：PURPOSE:The spatial resolution of iterative reconstruction (IR) in computed tomography (CT) is contrast- and noise-dependent because of the nonlinear regularization. Due to the severe noise contamination, it is challenging to perform precise spatial-resolution measurements at very low-contrast levels. The purpose of th...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4916802
更新日期：2015-05-01 00:00:00
abstract：PURPOSE:Monitoring of physiological parameters is a major concern in Intensive Care Units (ICU) given their role in the assessment of vital organ function. Within this context, one issue is the lack of efficient noncontact techniques for respiratory monitoring. In this paper, we present a novel noncontact solution for ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.14557
更新日期：2020-10-28 00:00:00
abstract：PURPOSE:To evaluate the feasibility of using an objective computer-aided system to assess bladder cancer stage in CT Urography (CTU). MATERIALS AND METHODS:A dataset consisting of 84 bladder cancer lesions from 76 CTU cases was used to develop the computerized system for bladder cancer staging based on machine learnin...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12510
更新日期：2017-11-01 00:00:00
abstract：PURPOSE:The aim of this study was to implement a Dirichlet process mixture (DPM) model for automatic tumor edge identification on (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) images by optimizing the parameters on which the algorithm depends, to validate it experimentally, and to test its robus...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4947123
更新日期：2016-05-01 00:00:00
abstract：:In this study, BrachyDose, a recently developed EGSnrc Monte Carlo code for rapid brachytherapy dose calculations, has been benchmarked by reproducing previously published dosimetry parameters for three brachytherapy seeds with varied internal structure and encapsulation. Calculations are performed for two 125I seeds ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2400843
更新日期：2007-02-01 00:00:00
abstract：:The aim of the present study is to examine the validity of using silicon semiconductor detectors in degraded electron beams with a broad energy spectrum and a wide angular distribution. A comparison is made with diamond detector measurements, which is the dosimeter considered to give the best results provided that dos...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1315317
更新日期：2000-11-01 00:00:00
abstract：PURPOSE:To develop a novel aperture-based algorithm for volumetric modulated are therapy (VMAT) treatment plan optimization with high quality and high efficiency. METHODS:The VMAT optimization problem is formulated as a large-scale convex programming problem solved by a column generation approach. The authors consider...
journal_title：Medical physics
pub_type： 信件
doi：10.1118/1.3491675
更新日期：2010-11-01 00:00:00
abstract：PURPOSE:Plastic scintillation detectors are used for dosimetry in small radiation fields with high dose gradients, e.g., provided by β-emitting sources like 106 Ru/106 Rh eye plaques. A drawback is a background signal caused by Cerenkov radiation generated by electrons passing the optical fibers (light guides) of this ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12374
更新日期：2017-09-01 00:00:00
abstract：:Effectiveness of an oral presentation depends on the ability of the speaker to communicate with the audience. An important part of this communication is focusing on two to five key points and emphasizing those points during the presentation. Every aspect of the presentation should be purposeful and directed at facilit...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4735944
更新日期：2012-06-01 00:00:00
abstract：:Intravascular brachytherapy requires that the dose be specified within millimeters of the source. High dose gradients near brachytherapy sources require that the source-detector distance be accurately known for dosimetry purposes. Solid phantoms can be designed to accommodate these stringent requirements. This study r...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1376176
更新日期：2001-06-01 00:00:00
abstract：:The method of images is employed to insert the effects of the presence of a single lateral boundary on contrast functions previously derived for an infinite slab using a random walk model of photon transport. The predictions of the model for zero and extrapolated boundary conditions are compared with Monte Carlo (MC) ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.598687
更新日期：1999-09-01 00:00:00
abstract：:An important aspect of the intensity modulated radiotherapy (IMRT) process is that of optimizing the beam intensity profiles. Most such methods use a comparison between the defined dose distribution (including prescription dose and dose limits for critical structures) and the current distribution. The comparison may i...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1428756
更新日期：2002-01-01 00:00:00
abstract：:Projected light fields are used on treatment simulators and teletherapy treatment units to delineate the size and position of the radiation beam. Any discrepancy between these fields will lead to a systematic field placement error, with possibly serious implications with regard to the accuracy of the delivered dose di...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.597867
更新日期：1996-07-01 00:00:00
abstract：:In order to determine accurately the relative x-ray intensities transmitted through the different steps of an aluminum stepwedge and incident on an image intensifier (II)-TV digital system, we used a 100-mm camera which was attached to the II output. The characteristic curves of an II-TV digital system, which relate t...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.595819
更新日期：1986-11-01 00:00:00
