Abstract:
:We are developing an automated stereo spot mammography technique for improved imaging of suspicious dense regions within digital mammograms. The technique entails the acquisition of a full-field digital mammogram, automated detection of a suspicious dense region within that mammogram by a computer aided detection (CAD) program, and acquisition of a stereo pair of images with automated collimation to the suspicious region. The latter stereo spot image is obtained within seconds of the original full-field mammogram, without releasing the compression paddle. The spot image is viewed on a stereo video display. A critical element of this technique is the automated detection of suspicious regions for spot imaging. We performed an observer study to compare the suspicious regions selected by radiologists with those selected by a CAD program developed at the University of Michigan. True regions of interest (TROIs) were separately determined by one of the radiologists who reviewed the original mammograms, biopsy images, and histology results. We compared the radiologist and computer-selected regions of interest (ROIs) to the TROIs. Both the radiologists and the computer were allowed to select up to 3 regions in each of 200 images (mixture of 100 CC and 100 MLO views). We computed overlap indices (the overlap index is defined as the ratio of the area of intersection to the area of interest) to quantify the agreement between the selected regions in each image. The averages of the largest overlap indices per image for the 5 radiologist-to-computer comparisons were directly related to the average number of regions per image traced by the radiologists (about 50% for 1 region/image, 84% for 2 regions/image and 96% for 3 regions/image). The average of the overlap indices with all of the TROIs was 73% for CAD and 76.8% +/- 10.0% for the radiologists. This study indicates that the CAD determined ROIs could potentially be useful for a screening technique that includes stereo spot mammography imaging.
journal_name
Med Physjournal_title
Medical physicsauthors
Goodsitt MM,Chan HP,Lydick JT,Gandra CR,Chen NG,Helvie MA,Bailey JE,Roubidoux MA,Paramagul C,Blane CE,Sahiner B,Petrick NAdoi
10.1118/1.1737492subject
Has Abstractpub_date
2004-06-01 00:00:00pages
1558-67issue
6eissn
0094-2405issn
2473-4209journal_volume
31pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract:PURPOSE:To describe Acuros® CTS, a new software tool for rapidly and accurately estimating scatter in x-ray projection images by deterministically solving the linear Boltzmann transport equation (LBTE). METHODS:The LBTE describes the behavior of particles as they interact with an object across spatial, energy, and dir...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12850
更新日期:2018-05-01 00:00:00
abstract:PURPOSE:To introduce a pair of accelerated non-Cartesian acquisition principles that when combined, exploit the periodicity of k-space acquisition, and thereby enable acquisition of high-temporal cine Cardiac Magnetic Resonance (CMR). METHODS:The mathematical formulation of a noniterative, undersampled non-Cartesian c...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12234
更新日期:2017-07-01 00:00:00
abstract::For radiation dosimetry calculations of radiolabeled monoclonal antibodies, (MAB), pharmacokinetics are critical. Specifically, pharmacokinetic modeling is a useful component of estimation of cumulated activity in various source organs in the body. It is thus important to formulate general methods of pharmacokinetic m...
journal_title:Medical physics
pub_type: 杂志文章,评审
doi:10.1118/1.597047
更新日期:1993-03-01 00:00:00
abstract:PURPOSE:The electronic portal imaging device (EPID) is a system for checking the patient setup; as a result of its integration with the linear accelerator and software customized for dosimetry, it is increasingly used for verification of the delivery of fixed-field intensity-modulated radiation therapy (IMRT). In order...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3271107
更新日期:2010-01-01 00:00:00
abstract:PURPOSE:The authors have recently developed a cine-mode T2*/T1-weighted 4D-MRI technique and a sequential-mode T2-weighted 4D-MRI technique for imaging respiratory motion. This study aims at investigating which 4D-MRI image acquisition mode, cine or sequential, provides more accurate measurement of organ motion during ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4938066
更新日期:2016-01-01 00:00:00
abstract:PURPOSE:To generate hybrid VMAT-IMRT treatment plans by utilizing an IMRT beam-angle-optimality (BAO) search under a commercially available TPS without the aid of custom optimization software or high performance computing. METHODS:The high dose modulation provided by IMRT beams can be exploited to improve the quality ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4735712
更新日期:2012-06-01 00:00:00
abstract:PURPOSE:To experimentally commission a dual-energy CT (DECT) joint statistical image reconstruction (JSIR) method, which is built on a linear basis vector model (BVM) of material characterization, for proton stopping power ratio (SPR) estimation. METHODS:The JSIR-BVM method builds on the relationship between the energ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.13287
更新日期:2019-01-01 00:00:00
abstract:PURPOSE:Accurately predicting outcome (i.e., overall survival (OS) time) for higher grade glioma (HGG) has great clinical value and would provide optimized guidelines for treatment planning. Radiomics focuses on revealing underlying pathophysiological information in biomedical images for disease analysis and demonstrat...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.13288
更新日期:2019-01-01 00:00:00
abstract:PURPOSE:To assess the temporal and spatial accuracy of the GateCT™ system (VisionRT, London, UK), a recently released respiratory tracking system for 4DCT, under both ideal and nonideal respiratory conditions. METHODS:Three experiments were performed by benchmarking and comparing its results with the ground-truth inpu...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3671941
更新日期:2012-01-01 00:00:00
abstract::Backscatter factors for kVps and half-value layers typical of mammographic beams have been determined as a function of beam diameter and half-value layer. The method utilized thin TLD-100 chips with the scattering medium alternately present and absent. Results indicate that the field-size dependence of the backscatter...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.594312
更新日期:1977-09-01 00:00:00
abstract::The number of intensity modulated radiation therapy (IMRT) procedures is continuously growing worldwide and it is necessary to develop tools for patient specific quality assurance (QA) that avoid using machine time that could be employed in treating additional patients. One way of achieving this goal is to perform a m...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2815359
更新日期:2008-01-01 00:00:00
abstract:PURPOSE:To propose a method to calculate the tissue phantom ratio (TPR) using the depth dose and to compare the proposed method with two other methods. METHODS:An analytical dose model from Bjärngard was used to describe the depth dose and the TPR. The parameters of the model were derived from depth dose measurements,...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3570575
更新日期:2011-05-01 00:00:00
abstract::Cardiac arrhythmias are a major health burden, associated with reduced quality of life and substantial morbidity and mortality. Current therapy includes moderately effective medication and catheter-based ablation of arrhythmogenic substrates in the heart. Catheter interventions frequently have to be repeated due to re...
journal_title:Medical physics
pub_type: 杂志文章,评审
doi:10.1002/mp.12595
更新日期:2018-11-01 00:00:00
abstract::A detailed derivation is presented of the formulas required to determine Ngas and Dmed in the AAPM TG-21 dosimetry protocol. This protocol specifies how to determine the absorbed dose in an electron or photon beam when using exposure or absorbed dose calibrated ion chambers. It is shown that the expression given in TG...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.596292
更新日期:1988-01-01 00:00:00
abstract::A beam intensity monitor was tested in a 230-MeV proton beam at the Loma Linda Proton Therapy Accelerator during its commissioning at Fermi National Accelerator Laboratory. The intensity monitor was designed to regulate the beam intensity extracted from the proton synchrotron. The proton beam is tunable between 70 and...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.596636
更新日期:1991-07-01 00:00:00
abstract:PURPOSE:For accurate tissue inhomogeneity correction in radiotherapy treatment planning, the authors had previously proposed a novel conversion of the energy-subtracted CT number to an electron density (ΔHU-ρe conversion), which provides a single linear relationship between ΔHU and ρe over a wide ρe range. The purpose ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4881327
更新日期:2014-07-01 00:00:00
abstract:PURPOSE:Positron emission tomography (PET) is an important tool for nuclear medical imaging. It has been widely used in clinical diagnosis, scientific research, and drug testing. PET is a kind of emission computed tomography. Its basic imaging principle is to use the positron annihilation radiation generated by radionu...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.13804
更新日期:2019-11-01 00:00:00
abstract::Transmission data for 4-MV bremsstrahlung beams have been measured with a combination of lead and aluminum attenuators. From these data, the original energy spectra have been reconstructed using an iterative least-squares technique, previously evaluated by simulation studies. The spectra on the central axis for three ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.595356
更新日期:1983-11-01 00:00:00
abstract::Scanning film densitometry routinely used for obtaining dosimetric information about therapy treatment beams is subject to several sources of inaccuracies. The most significant of these are described and appropriate methods of testing are presented. This establishes the need for adequate acceptance testing followed by...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.595407
更新日期:1983-09-01 00:00:00
abstract:PURPOSE:To develop a pharmacokinetic modelfree framework to analyze the dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) data for assessment of response of brain metastases to radiation therapy. METHODS:Twenty patients with 45 analyzable brain metastases had MRI scans prior to whole brain radiation thera...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4842556
更新日期:2014-01-01 00:00:00
abstract::The performance of an indirect-detection, active matrix flat-panel imager (FPI) at diagnostic energies is reported in terms of measured and theoretical signal size, noise power spectrum (NPS), and detective quantum efficiency (DQE). Based upon a 1536 x 1920 pixel, 127 microns pitch array of a-Si:H thin-film transistor...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.598243
更新日期:1998-05-01 00:00:00
abstract::Coherent scattering of x-ray photons leads to the phenomenon of x-ray diffraction, which is widely used for determining atomic structure in materials science. A technique [x-ray diffraction computed tomography (CT)] is described, analogous to conventional CT, in which the x-ray diffraction properties of a stack of two...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.596063
更新日期:1987-07-01 00:00:00
abstract:PURPOSE:As the predominant driver of respiratory motion, the diaphragm represents a key surrogate for motion management during the irradiation of thoracic cancers. Existing approaches to diaphragm tracking often produce phase-based estimates, suffer from lateral side failures or are not executable in real-time. In this...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.13738
更新日期:2019-10-01 00:00:00
abstract::The precision of noninvasive optical measurement of the concentration changes in oxy-, deoxy-, and total-hemoglobin depends on wavelength. For estimating the precision, we calculated the noise level of the concentration changes as the uncertainty in measurements using several wavelength pairs of light. Seven laser dio...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1373401
更新日期:2001-06-01 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:Magnetic resonance imaging (MRI) is increasingly used for radiotherapy target delineation, image guidance, and treatment response monitoring. Recent studies have shown that an entire external x-ray radiotherapy treatment planning (RTP) workflow for brain tumor or prostate cancer patients based only on MRI refer...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4958677
更新日期:2016-08-01 00:00:00
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, ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.594657
更新日期:1980-01-01 00:00:00
abstract:PURPOSE:The objective of this study is to evaluate requirements for radionuclide-based solid tumor therapy by assessing the radial dose distribution of beta-particle-emitting and alpha-particle-emitting molecules localized either solely within endothelial cells of tumor vasculature or diffusing from the vasculature thr...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3431999
更新日期:2010-06-01 00:00:00
abstract:PURPOSE:Conformal SBRT plans for Lung cancer with static gantry angles are ideal candidates for applying motion tracking because of: (1) better dosimetric conformity with reduced target margin and (2) easier and more faithful target tracking without intensity modulation. This work is to demonstrate that by delivering t...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4734998
更新日期:2012-06-01 00:00:00
abstract:PURPOSE:Intensity-modulated proton therapy (IMPT) is known to be sensitive to patient setup and range uncertainty issues. Multiple robust optimization methods have been developed to mitigate the impact of these uncertainties. Here, we propose a new robust optimization method, which provides an alternative way of robust...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.13276
更新日期:2019-01-01 00:00:00