Abstract：
:Using stable materials capable of mimicking any soft tissues of the human body--quantitatively with respect to speed of sound, density, and attenuation coefficient and semiquantitatively with respect to scatter--we have constructed a torso section phantom containing simulated bowel gas, kidney, kidney fat pad, liver, tumor, cyst, bony structures, and resolution fibers. Simple geometries and precise knowledge of ultrasonic properties allow artifacts to be produced and explained with great confidence. Artifacts due to refraction and reflection are particularly dramatic. Phantoms such as this should be useful as stage one phantoms for training ultrasonographers. Such phantoms should also be of use to those who are doing research in ultrasonic image processing. This might involve, for example, recognizing image artifacts and reducing their effect in the formation of the image.
journal_name
Med Physjournal_title
Medical physicsauthors
Madsen EL,Zagzebski JA,Ghilardi-Netto Tdoi
10.1118/1.594657subject
Has Abstractpub_date
1980-01-01 00:00:00pages
43-50issue
1eissn
0094-2405issn
2473-4209journal_volume
7pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract：:Heating rate (HR) patterns in cylindrical structures were studied with inhomogeneous limb phantoms. These phantoms, arm and thigh models consisting of fat, bone, and muscle material, were heated with Clini-Therm L, M, and MS applicators at 915 MHz. The thigh model is 18 cm in diameter with 2.65-cm-thick fat on the out...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596627
更新日期：1991-11-01 00:00:00
abstract：PURPOSE:An electrically floating radio frequency (RF) shielded PET insert with individual PET detectors shielded by separate Faraday cages enables the MRI built-in body RF coil to be used at least as an RF transmitter, in which the RF field penetrates the imaging region inside the PET ring through the narrow gaps betwe...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.13132
更新日期：2018-10-01 00:00:00
abstract：:To improve beam penetration into a head allowing the treatment of deeper seated tumors, two neutron collimators were built sequentially and tested for use in the clinical boron neutron capture therapy (BNCT) program at the epithermal neutron irradiation facility of the Brookhaven Medical Research Reactor. The collimat...
journal_title：Medical physics
pub_type： 临床试验,杂志文章
doi：10.1118/1.597772
更新日期：1996-12-01 00:00:00
abstract：PURPOSE:Researchers write many computer programs with unique implementations, usually requiring a great amount of effort for other researchers to learn how to install, configure, and use. Some programs require specialized hardware platforms such as GPU workstation or CPU cluster, which may not readily available for man...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4735274
更新日期：2012-06-01 00:00:00
abstract：INTRODUCTION:Ultrasound (US) guidance of the prostate has long been conducted using a transabdominal (TA) approach. More recently, a transperineal (TP) approach has been made available for image guidance. Our aim was to determine if both methods produced similar alignments within the same patients. MATERIALS AND METHO...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.14522
更新日期：2020-12-01 00:00:00
abstract：:One of the important features of the Siemens Virtual Wedge (VW) is that the VW factor (VWF) is approximately equal to unity for all beams with a total deviation for a given wedge no greater than 0.05, as specified by Siemens. In this note we report the observed dependence of VWF on dose calibration (cGy/MU), monitor u...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1344204
更新日期：2001-02-01 00:00:00
abstract：:A scintillation dosemeter is calibrated for 90Sr/90Y beta rays from an ophthalmic applicator, using an extrapolation ionization chamber as a reference instrument. The calibration factor for the scintillation dosemeter agrees with that given by the manufacturer of the dosemeter within ca. 2%. The estimated overall unce...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1709490
更新日期：2004-05-01 00:00:00
abstract：PURPOSE:Helical tomotherapy is a complex delivery technique, integrating CT image guidance and intensity modulated radiotherapy in a single system. The integration of the CT detector ring on the gantry not only allows patient position verification but is also often used to perform various QA procedures. This convenienc...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3566067
更新日期：2011-04-01 00:00:00
abstract：PURPOSE:To increase diagnostic accuracy of breast MRI by increasing temporal resolution and more accurately sampling the early kinetics of contrast media uptake. We tested the feasibility of accelerating bilateral breast DCE-MRI by reducing the FOV, allowing aliasing, and unfolding the resulting images. METHODS:Previo...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12747
更新日期：2018-03-01 00:00:00
abstract：PURPOSE:The purpose of this study was to develop a dual-modality positron emission tomography (PET)/magnetic resonance imaging (MRI) with insertable PET for simultaneous PET and MR imaging of the human brain. METHODS:The PET detector block was composed of a 4 × 4 matrix of detector modules, each consisting of a 4 × 4 ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4918321
更新日期：2015-05-01 00:00:00
abstract：:Anisotropy of dose distributions around 103Pd, 125I, and 192Ir sources for interstitial brachytherapy was examined. Dose rates around 125I models 6702 and 6711 and 192Ir sources were measured using lithium fluoride thermoluminescence dosimeters (LiF TLDs) in a water-equivalent, solid phantom. From these measured data ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.597110
更新日期：1993-09-01 00:00:00
abstract：:We are developing computerized methods for characterizing the bone texture pattern from digitized skeletal radiographs. For this method to be useful clinically, it must be able to distinguish between weak and strong bone under the range of exposure conditions potentially encountered in the clinical setting. In this st...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.598858
更新日期：2000-01-01 00:00:00
abstract：:Anatomy-based positron emission tomography (PET) image enhancement techniques have been shown to have the potential for improving PET image quality. However, these techniques assume an accurate alignment between the anatomical and the functional images, which is not always valid when imaging the chest due to respirato...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2804721
更新日期：2007-12-01 00:00:00
abstract：PURPOSE:High-Z material in computed tomography (CT) yields metal artifacts that degrade image quality and may cause substantial errors in dose calculation. This study couples a metal artifact reduction (MAR) algorithm with enhanced 16-bit depth (vs standard 12-bit) to quantify potential gains in image quality and dosim...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4805102
更新日期：2013-06-01 00:00:00
abstract：:The authors describe a method for directly digitizing optical images with a photostimulable phosphor (PSP) system. A PSP plate is initially charged with an exposure to a uniform x-ray field, and is then exposed to an optical image which discharges the plate in relation to the amount of incident light. Two applications...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596917
更新日期：1992-07-01 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
abstract：PURPOSE:To determine the accuracy and reproducibility of the automatic- setup procedure of a 3D water scanner (3D SCANNER, Sun Nuclear Corp). The procedure automatically aligns the scanner's coordinate system to the Linac coordinate system. A unique off-center detector holder extends the scan range to 630 mm, eliminati...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4734668
更新日期：2012-06-01 00:00:00
abstract：PURPOSE:A new motion-based gated proton therapy for the treatment of orbital tumors using real-time eye-tracking system was designed and evaluated. METHODS:We developed our system by image-pattern matching, using a normalized cross-correlation technique with LabVIEW 8.6 and Vision Assistant 8.6 (National Instruments, ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4729708
更新日期：2012-07-01 00:00:00
abstract：:The Anisotropic Analytical Algorithm (AAA) of the Varian Eclipse treatment planning system calculates absolute dose for a variety of beam settings including those with an enhanced dynamic wedge (EDW). This algorithm has gone through a number of version updates since it was first released in July 2005. Previous version...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2965929
更新日期：2008-07-01 00:00:00
abstract：:An experiment to determine the peak of the energy spectrum of the photon beam from a Toshiba LMR-15 medical linear accelerator is described. It is found that the flattening filters removed much of the bremsstrahlung spectrum below approximately 1 MeV, resulting in a photon spectrum which peaks around 1.2 MeV. ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.595582
更新日期：1984-11-01 00:00:00
abstract：:In the presence of intrafraction organ motion, target localization uncertainty can greatly hamper the advantage of highly conformal dose techniques such as intensity modulated radiation therapy (IMRT). To minimize the adverse dosimetric effect caused by tumor motion, a real-time knowledge of the tumor position is requ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2842072
更新日期：2008-04-01 00:00:00
abstract：:Statistical image reconstruction (SIR) methods have shown potential to substantially improve the image quality of low-dose x-ray computed tomography (CT) as compared to the conventional filtered back-projection (FBP) method. According to the maximum a posteriori (MAP) estimation, the SIR methods are typically formulat...
journal_title：Medical physics
pub_type： 杂志文章,评审
doi：10.1002/mp.13123
更新日期：2018-10-01 00:00:00
abstract：:During the past decade the use of undersampled acquisition and constrained reconstruction have led to significant increases in data acquisition speed, SNR, spatial resolution and temporal resolution in MR imaging. When a separately acquired constraining image is combined with an angiographic time series the traditiona...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4735797
更新日期：2012-06-01 00:00:00
abstract：PURPOSE:We investigated the feasibility of proton tomosynthesis as daily positioning of patients and compared the results with photon tomosynthesis as an alternative to conventional portal imaging or on-board cone-beam computed tomography. METHODS:Dedicated photon-like proton beam using the passively scattered proton ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4734898
更新日期：2012-06-01 00:00:00
abstract：PURPOSE:Several new technologies for single photon emission computed tomography (SPECT) instrumentation with parallel-hole collimation have been proposed to improve detector sensitivity and signal collection efficiency. Benefits from improved signal efficiency include shorter acquisition times and lower dose requiremen...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4897567
更新日期：2014-11-01 00:00:00
abstract：:Nowadays, digital subtraction angiography systems must be able to sustain real-time acquisition (30 frames per second) of 512 x 512 x 8 bit images and store several sequences of such images on low cost and general-purpose mass memories. Concretely, that means a 7.8 Mbytes per second rate and about 780 Mbytes disk spac...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596309
更新日期：1989-11-01 00:00:00
abstract：PURPOSE:A commonly used beam quality index (Q) for high-energy photon beams is the tissue phantom ratio (TPR20,10) for a square field of 10 x 10 cm2 and SDD of 100 cm. On some specialized radiotherapy treatment equipment such a reference collimator setting is not achievable. Likewise a flat beam profile, not explicitly...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3197062
更新日期：2009-09-01 00:00:00
abstract：:A single-field rotational total skin electron irradiation technique has recently been developed at the McGill University for treatment of skin malignancies. The dose received by a given surface point during rotation in a uniform large electron field depends on the radius of rotation of the surface point, on the local ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.595524
更新日期：1984-07-01 00:00:00
abstract：:Patient-specific intensity-modulated radiotherapy (IMRT) verifications require an accurate two-dimensional dosimeter that is not labor-intensive. We assessed the precision and reproducibility of film calibrations over time, measured the elemental composition of the film, measured the intermittency effect, and measured...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1852791
更新日期：2005-02-01 00:00:00
abstract：PURPOSE:It is very important for calculation of clinical indices and diagnosis to detect thyroid nodules from ultrasound images. However, this task is a challenge mainly due to heterogeneous thyroid nodules with distinct components are similar to background in ultrasound images. In this study, we employ cascade deep co...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12134
更新日期：2017-05-01 00:00:00
