Abstract:
:In this article, we present a characterization of the effect of difference of Gaussians (DoG) filters in the detection of mammographic regions. DoG filters have been used previously in mammographic mass computer-aided detection (CAD) systems. As DoG filters are constructed from the subtraction of two bivariate Gaussian distributions, they require the specification of three parameters: the size of the filter template and the standard deviations of the constituent Gaussians. The influence of these three parameters in the detection of mammographic masses has not been characterized. In this work, we aim to determine how the parameters affect (1) the physical descriptors of the detected regions, (2) the true and false positive rates, and (3) the classification performance of the individual descriptors. To this end, 30 DoG filters are created from the combination of three template sizes and four values for each of the Gaussians' standard deviations. The filters are used to detect regions in a study database of 181 craniocaudal-view mammograms extracted from the Digital Database for Screening Mammography. To describe the physical characteristics of the identified regions, morphological and textural features are extracted from each of the detected regions. Differences in the mean values of the features caused by altering the DoG parameters are examined through statistical and empirical comparisons. The parameters' effects on the true and false positive rate are determined by examining the mean malignant sensitivities and false positives per image (FPpI). Finally, the effect on the classification performance is described by examining the variation in FPpI at the point where 81% of the malignant masses in the study database are detected. Overall, the findings of the study indicate that increasing the standard deviations of the Gaussians used to construct a DoG filter results in a dramatic decrease in the number of regions identified at the expense of missing a small number of malignancies. The sharp reduction in the number of identified regions allowed the identification of textural differences between large and small mammographic regions. We find that the classification performances of the features that achieve the lowest average FPpI are influenced by all three of the parameters.
journal_name
Med Physjournal_title
Medical physicsauthors
Catarious DM Jr,Baydush AH,Floyd CE Jrdoi
10.1118/1.2358326subject
Has Abstractpub_date
2006-11-01 00:00:00pages
4104-14issue
11eissn
0094-2405issn
2473-4209journal_volume
33pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全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::Topographic treatment is a radiation therapy delivery technique for fixed-gantry (nonrotational) treatments on a helical tomotherapy system. The intensity-modulated fields are created by moving the treatment couch relative to a fan-beam positioned at fixed gantry angles. The delivered dose distribution is controlled b...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2216876
更新日期:2006-08-01 00:00:00
abstract:PURPOSE:This article introduces the use of low power continuous wave frequency modulated radar for medical applications, specifically for remote monitoring of vital signs in patients. METHODS:Gigahertz frequency radar measures the electromagnetic wave signal reflected from the surface of a human body and from tissue b...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3267038
更新日期:2010-03-01 00:00:00
abstract:PURPOSE:The response of alanine solid state dosimeters to ionizing radiation strongly depends on particle type and energy. Due to nuclear interactions, neutron fields usually also consist of secondary particles such as photons and protons of diverse energies. Various experiments have been carried out in three different...
journal_title:Medical physics
pub_type: 杂志文章,多中心研究
doi:10.1118/1.4901299
更新日期:2015-01-01 00:00:00
abstract::We have reported in our previous studies on the methodology, and feasibility of 4D-PET (Gated PET) acquisition, to reduce respiratory motion artifact in PET imaging of the thorax. In this study, we expand our investigation to address the problem of respiration motion in PET/CT imaging. The respiratory motion of four l...
journal_title:Medical physics
pub_type: 临床试验,杂志文章
doi:10.1118/1.1809778
更新日期:2004-12-01 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::The anti-scatter grid has been widely used to reject scatter and increase the perceptibility of a low-contrast object in chest radiography; however, it also attenuated the primary x-rays, resulting in a substantial loss of information and an increased relative noise level in heavily attenuated regions. A more dose eff...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2739805
更新日期:2007-07-01 00:00:00
abstract:PURPOSE:A long-standing conundrum is why photoacoustic tomography (PAT) possesses the unique ability to produce images devoid of speckle artifacts while all other coherent imaging technologies do not. METHODS:In this paper, we explain the inherent mechanism that suppresses speckle in PAT, and the analysis was validate...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3187231
更新日期:2009-09-01 00:00:00
abstract:PURPOSE:Metal artifact reduction (MAR) is a major problem and a challenging issue in x-ray computed tomography (CT) examinations. Iterative reconstruction from sinograms unaffected by metals shows promising potential in detail recovery. This reconstruction has been the subject of much research in recent years. However,...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4950722
更新日期:2016-06-01 00:00:00
abstract:PURPOSE:To investigate the feasibility of implementing a novel approach for patient-specific QA of TomoDirect(TM) whole breast treatment. METHODS:The most currently used TomoTherapy DQA method, consisting in the verification of the 2D dose distribution in a coronal or sagittal plane of the Cheese Phantom by means of g...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4722967
更新日期:2012-07-01 00:00:00
abstract::The objective of this work is to assess the suitability and performance of a new dosimeter system with a novel geometry for the quality assurance (QA) of volumetric modulated arc therapy (VMAT). The new dosimeter system consists of a hollow cylinder (15 and 25 cm inner and outer diameters) with 124 diodes embedded in ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3117563
更新日期:2009-05-01 00:00:00
abstract::The purpose of this paper is to develop a method that reduces the number of segments for intensity modulated arc therapy (IMAT) and intensity modulated radiotherapy (IMRT) for concave target volumes (TV). The aim was to utilize no more than two intensity levels per organ at risk (OAR) and to derive both optimal segmen...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1861161
更新日期:2005-03-01 00:00:00
abstract:PURPOSE:To investigate the inconsistency of recent literature on the effect of magnetic field on the response of radiochromic films, we studied the influence of 0.35 T magnetic field on dosimetric response of EBT3 and EBT-XD GafchromicTM films. METHODS:Two different models of radiochromic films, EBT3 and EBT-XD, were ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.14313
更新日期:2020-09-01 00:00:00
abstract::A prototype Emission-Transmission Computed Tomography (ETCT) system is being developed that will acquire single-slice x-ray transmission CT images simultaneously with single photon emission computed tomography (SPECT) images. This system will permit the correlation of anatomical information from x-ray CT with function...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.596643
更新日期:1991-09-01 00:00:00
abstract:PURPOSE:To evaluate dependence of measured dose on size and location of region of interest (ROI) in Gafchromic EBT3 film dosimetry. METHODS:Gafchromic EBT3 films were irradiated perpendicularly using the 6MV beam from a linear accelerator at 10 cm depth (100 cm SSD) of a 30 × 30 × 20 cm3 solid water phantom for a rang...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12885
更新日期:2018-05-01 00:00:00
abstract:PURPOSE:The purpose of this study was to investigate the potential of MR-guided pulsed focused ultrasound (pFUS) for the enhancement of drug uptake in prostate tumors in vivo using doxorubicin (Dox). METHODS:An antitumor drug Dox, an orthotopic animal prostate tumor model using human prostate cancer, LNCaP cell line, ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4705346
更新日期:2012-05-01 00:00:00
abstract::Modulation of the activity of the subthalamic nucleus (STN) using deep brain stimulation (DBS) in patients with advanced Parkinson's disease is the most common procedure performed today by functional neurosurgeons. The STN contours cannot be entirely identified on common 1.5 T images; in particular, the ventromedial b...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2936229
更新日期:2008-07-01 00:00:00
abstract::This study presents experimental results about the effective depth of penetration and about the radiofrequency (rf) power absorption in humans as a function of frequency. The frequency range investigated covers 10 up to 220 MHz. For the main part, the results were derived from bench measurements of the quality factor ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.595995
更新日期:1987-11-01 00:00:00
abstract:PURPOSE:Two types of tumor hypoxia most likely exist in human cancers: Chronic hypoxia due to the paucity of blood capillaries and acute hypoxia due to temporary shutdoWn of microvasculatures or fluctuation in the red cell flux. In a recent hypoxia imaging study using 18F-FMISO PET, the authors observed variation in tr...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3213092
更新日期:2009-10-01 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:PURPOSE:Total and regional body composition are important indicators of health and mortality risk, but their measurement is usually restricted to controlled environments in clinical settings with expensive and specialized equipment. A method that approaches the accuracy of the current gold standard method, dual-energy ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.14492
更新日期:2020-12-01 00:00:00
abstract:PURPOSE:Stray neutron radiation is of concern after radiation therapy, especially in children, because of the high risk it might carry for secondary cancers. Several previous studies predicted the stray neutron exposure from proton therapy, mostly using Monte Carlo simulations. Promising attempts to develop analytical ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4829512
更新日期:2013-12-01 00:00:00
abstract::The radiation dose to the lungs from 133Xe in lung air is directly proportional to the time integral of 133Xe concentration; i.e., the cumulated concentration in the lungs. Using kinetic models developed to fit clinical observations, we have studied the effect of retention on cumulated concentration in lung air. The m...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.594341
更新日期:1977-11-01 00:00:00
abstract:PURPOSE:This study introduces a new hybrid ZTE/Dixon MR-based attenuation correction (MRAC) method including bone density estimation for PET/MRI and quantifies the effects of bone attenuation on metastatic lesion uptake in the pelvis. METHODS:Six patients with pelvic lesions were scanned using fluorodeoxyglucose (18F-...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12122
更新日期:2017-03-01 00:00:00
abstract::The purpose of this work is to demonstrate a proof of feasibility of the application of a commercial prototype deformable model algorithm to the problem of delineation of anatomic structures on four-dimensional (4D) computed tomography (CT) image data sets. We acquired a 4D CT image data set of a patient's thorax that...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1929207
更新日期:2005-07-01 00:00:00
abstract:PURPOSE:Recent advances in compressed sensing (CS) enable accurate CT image reconstruction from highly undersampled and noisy projection measurements, due to the sparsifiable feature of most CT images using total variation (TV). These novel reconstruction methods have demonstrated advantages in clinical applications wh...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4729837
更新日期:2012-07-01 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::Conventional chest radiography is limited by the presence of scattered radiation and the small useful exposure range of radiographic film. A computer-assisted scanning system to minimize these two effects is outlined. The system uses a small beam of radiation swept over the patient's chest in a raster pattern to expos...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.595327
更新日期:1983-09-01 00:00:00
abstract:PURPOSE:Severe artifacts in kilovoltage-CT simulation images caused by large metallic implants can significantly degrade the conspicuity and apparent CT Hounsfield number of targets and anatomic structures, jeopardize the confidence of anatomical segmentation, and introduce inaccuracies into the radiation therapy treat...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4762814
更新日期:2012-12-01 00:00:00
abstract:PURPOSE:To review the issues a physicist may encounter in a community hospital during the transition from film/paper charts to a paperless environment with ARIA and a TrueBeam LINAC. With a lean budget, it was necessary for the physics group to take on the project management responsibilities in order save costs. This w...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4735291
更新日期:2012-06-01 00:00:00