Abstract：
:The optimum x-ray spectra for acquisition of digital mammographic images using an amorphous selenium (a-Se) photoconductor are investigated. The recorded images consist of latent charge distributions on the surface of an a-Se plate, which are then read out using two methods, laser discharge, or flat panel recharge. The investigation is based on a model of the breast previously developed for a phosphor-based digital readout system, and has been extended to include the effects specific to the use of photoconductors. The effects of plate thickness, x-ray scatter, readout noise, dose, and the kind of breast tissue on the nature of the optimum spectrum are explored for the two readout methods. The results indicate that use of a kilovoltage setting in the current mammographic range, and a molybdenum target spectrum is appropriate for digital readout of a-Se detectors. This conclusion contrasts with the appreciably higher kilovoltages traditionally used with the xerographic (toner) readout of latent charge images on a-Se.
journal_name
Med Physjournal_title
Medical physicsauthors
Fahrig R,Rowlands JA,Yaffe MJdoi
10.1118/1.597688subject
Has Abstractpub_date
1996-04-01 00:00:00pages
557-67issue
4eissn
0094-2405issn
2473-4209journal_volume
23pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract：PURPOSE:The purpose of this study was to detect and analyze anomalies between a large number of computed tomography (CT) scanners, tracked over time, utilized to collect human pulmonary CT data for a national multicenter study: chronic obstructive pulmonary disease genetic epidemiology study (COPDGene). METHODS:A cust...
journal_title：Medical physics
pub_type： 杂志文章,多中心研究
doi：10.1118/1.4747342
更新日期：2012-09-01 00:00:00
abstract：PURPOSE:To determine the accuracy and test-retest repeatability of fast radiofrequency (RF) transmit measurement approaches used in Dynamic Contrast Enhanced Magnetic Resonance Imaging (DCE-MRI). Spatial variation in the transmitted RF field introduces bias and increased variance in quantitative DCE-MRI metrics includi...
journal_title：Medical physics
pub_type： 杂志文章,多中心研究
doi：10.1002/mp.13518
更新日期：2019-06-01 00:00:00
abstract：PURPOSE:To quantitatively characterize the interfractional anatomic variations in post-operative radiation therapy (RT) for prostate bed, so that appropriate strategy that can fully address these variations can be developed. METHODS:A total of 102 daily pre-treatment CT acquired using an in-room CT (CTVision, Siemens)...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4734844
更新日期：2012-06-01 00:00:00
abstract：:Optimal visualization of moving structures such as the heart and coronary arteries using digital radiographic imaging systems is a difficult problem that can involve tradeoffs between temporal, spatial, and density resolution. The motion dependence of four angiographic measures of vessel dimensions is given and demons...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.595651
更新日期：1985-11-01 00:00:00
abstract：PURPOSE:To compare and evaluate intensity-based registration methods for computation of serial x-ray mammogram correspondence. METHODS:X-ray mammograms were simulated from MRIs of 20 women using finite element methods for modeling breast compressions and employing a MRI/x-ray appearance change model. The parameter con...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3457470
更新日期：2010-09-01 00:00:00
abstract：PURPOSE:Timely identification of systematic changes in radiation delivery of an imaging system can lead to a reduction in risk for the patients involved. However, existing quality assurance programs involving the routine testing of equipment performance using phantoms are limited in their ability to effectively carry o...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3524224
更新日期：2011-01-01 00:00:00
abstract：:Surgical guidance with fluorescence has been demonstrated in individual clinical trials for decades, but the scientific and commercial conditions exist today for a dramatic increase in clinical value. In the past decade, increased use of indocyanine green based visualization of vascular flow, biliary function, and tis...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4951732
更新日期：2016-06-01 00:00:00
abstract：:A computationally efficient pseudodynamical filtering setup is established for elasticity imaging (i.e., reconstruction of shear modulus distribution) in soft-tissue organs given statically recorded and partially measured displacement data. Unlike a regularized quasi-Newton method (QNM) that needs inversion of ill-con...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3158808
更新日期：2009-08-01 00:00:00
abstract：PURPOSE:To develop a computer-driven and thus less user-dependent method, allowing for a simple and straightforward generation of a Monte Carlo (MC) beam model of a scanned proton and carbon ion beam delivery system. METHODS:In a first step, experimental measurements were performed for proton and carbon ion energies i...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.14647
更新日期：2020-12-07 00:00:00
abstract：PURPOSE:To compare optimization characteristics, plan quality, and treatment delivery efficiency between total marrow irradiation (TMI) plans using the new TomoTherapy graphic processing unit (GPU) based dose engine and CPU/cluster based dose engine. METHODS:Five TMI plans created on an anthropomorphic phantom were op...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4810936
更新日期：2013-07-01 00:00:00
abstract：:Proton therapy offers the potential for excellent dose conformity and reduction in integral dose. The superior dose distribution is, however, much more sensitive to changes in radiological depths along the beam path than for photon fields. Respiratory motion can cause such changes for treatments sites like lung, liver...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2756602
更新日期：2007-08-01 00:00:00
abstract：PURPOSE:Optically stimulated luminescence (OSL) dosimetry has been recently introduced in radiation therapy as a potential alternative to the thermoluminescent dosimeter (TLD) system. The aim of this study was to investigate the feasibility of using OSL point dosimeters in the energy range used in diagnostic imaging. ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3602456
更新日期：2011-07-01 00:00:00
abstract：:The purpose of this work is to show the feasibility of using in vivo proton radiography of a radiotherapy patient for the patient individual optimization of the calibration from CT-Hounsfield units to relative proton stopping power. Water equivalent tissue (WET) calibrated proton radiographs of a dog patient treated f...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1833041
更新日期：2005-01-01 00:00:00
abstract：:Variations in the atomic composition, and mass and electron densities of polystyrene and polymethylmethacrylate (PMM) plastics were assessed from experimentally determined mass attenuation coefficients for 125I and 137Cs gamma rays. The means and standard deviations in the mass densities of 16 samples of PMM and 10 sa...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.594528
更新日期：1979-03-01 00:00:00
abstract：:The line spread function (LSF) of an imaging system incorporating a pinhole of 0.275 cm radius and a scintillation camera has been measured and its full width at half maximum (FWHM) compared to the values predicted by an expression based on the resolution index of Anger. In most cases, the actual resolution of the sys...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.594755
更新日期：1980-09-01 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：PURPOSE:The aim of this work was to provide a novel description of how the radiotherapy community configures treatment planning system (TPS) radiation beam models for clinically used treatment machines. Here we describe the results of a survey of self-reported TPS beam modeling parameter values across different C-arm l...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.13892
更新日期：2020-01-01 00:00:00
abstract：:The computed tomography (CT) radiation dose to pediatric patients has received considerable attention recently. Moreover, it is important to be able to determine CT radiation doses for various patient sizes ranging from infants to large adults. The current AAPM protocol only measures CT radiation dose using a 16 cm ac...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1543149
更新日期：2003-03-01 00:00:00
abstract：PURPOSE:A dosimetry evaluation model for treatment planning of esophageal radiation therapy is developed using a deep learning model. The model predicts dose volume histogram (DVH) from distance to target histogram (DTH) based on stacked de-noise auto-encoder (SDAE) and one-dimensional convolutional network (1D-CN). M...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.14434
更新日期：2020-10-01 00:00:00
abstract：:Electron-beam characteristics of a Philips SL25 linear accelerator have been studied. Central-axis percentage depth doses, cross-beam profiles and beam output factors of 6-, 10-, and 20-MeV beams, selected from the available energy range of 4 to 22 MeV, are reported in this paper. The main thrust of this work is to de...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596471
更新日期：1990-07-01 00:00:00
abstract：PURPOSE:To evaluate the energy dependence of Gafchromic EBT3 film for establishing a quality assurance method of bolus electron conformal radiotherapy. METHODS:We irradiated electron beam to EBT3 films, which were set in the water tank. The linear accelerator used was Varian Clinac 21EX. The energy of electron beams w...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4735200
更新日期：2012-06-01 00:00:00
abstract：PURPOSE:Color images are visualized on medical monitors that are adjusted by a grayscale standard display function (GSDF) or γ2.2. Although the GSDF is visually displayed as a linear graded grayscale, it does not specify how color medical images should be presented. On the other hand, the usual gamma setting for color ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.13532
更新日期：2019-06-01 00:00:00
abstract：:Electron beam dosimetry at low monitor unit (MU) settings is important for dosimetric applications. Dose linearity, beam flatness, and beam energies were studied at low MU settings with various dose rates for different types of linear accelerators. It is observed that for the scattering foil units, the dose/MU is a sm...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.597328
更新日期：1994-06-01 00:00:00
abstract：:Photon point dose kernels and absorbed fractions were generated in water for the full photon emission spectrum of each radionuclide of interest in nuclear medicine, by simulating the transport of particles using Monte Carlo. The kernels were then fitted to a mathematical expression. Absorbed fractions for point source...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.597670
更新日期：1996-05-01 00:00:00
abstract：PURPOSE:To investigate how using different sets of decision criteria impacts the quality of intensity modulated radiation therapy (IMRT) plans obtained by multiobjective optimization. METHODS:A multiobjective optimization evolutionary algorithm (MOEA) was used to produce sets of IMRT plans. The MOEA consisted of two i...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3589128
更新日期：2011-06-01 00:00:00
abstract：:Two acrylic cube phantoms have been constructed for BNCT applications that allow the depth distribution of neutrons to be measured with miniature 10BF3 detectors in 0.5-cm steps beginning at 1-cm depth. Sizes and weights of the cubes are 14 cm, 3.230 kg, and 11 cm, 1.567 kg. Tests were made with the epithermal neutron...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.598354
更新日期：1998-09-01 00:00:00
abstract：PURPOSE:The purpose of this study is to adapt an equivalent source model originally developed for conventional CT Monte Carlo dose quantification to the radiation oncology context and validate its application for evaluating concomitant dose incurred by a kilovoltage (kV) cone-beam CT (CBCT) system integrated into a lin...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4823795
更新日期：2013-11-01 00:00:00
abstract：PURPOSE:The feasibility of magnetic resonance image (MRI)-based proton therapy is based, among several other factors, on the implementation of appropriate extensions on current dose calculation methods. This work aims to develop a pencil beam algorithm (PBA) for dose calculation of proton beams within magnetic field re...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12854
更新日期：2018-05-01 00:00:00
abstract：PURPOSE:To describe an efficient method for verifying the size and centering of the radiation field from the Cyberknife IRIS variable collimator with sub-millimeter accuracy using a general purpose commercially available diode array. METHODS:We present a technique using a conventional diode array (Sun Nuclear Profiler...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4735220
更新日期：2012-06-01 00:00:00
abstract：:Spread of invasive carcinoma throughout breast tissue is believed to occur at supramolecular levels, beyond the range of standard histopathology identification. Small angle x-ray scattering (SAXS) is capable of characterizing the structural properties of collagen and tissue found in the breast at the scale of tens to ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3147144
更新日期：2009-07-01 00:00:00
