A CdZnTe slot-scanned detector for digital mammography.

abstract：PURPOSE:Anatomical variations occur during head and neck (H&N) radiotherapy treatment. kV cone-beam computed tomography (CBCT) images can be used for daily dose monitoring to assess dose variations owing to anatomic changes. Deep learning methods (DLMs) have recently been proposed to generate pseudo-CT (pCT) from CBCT ...

journal_title：Medical physics

authors： Barateau A,De Crevoisier R,Largent A,Mylona E,Perichon N,Castelli J,Chajon E,Acosta O,Simon A,Nunes JC,Lafond C

更新日期：2020-10-01 00:00:00

abstract：:A method for finding optimal primary fluence profiles for multiple field external beam radiation therapy techniques has been developed using a radiobiologically based objective function that quantifies the probability of achieving complication-free tumor control, P+. The objective function P+ has the valuable property...

journal_title：Medical physics

authors： Södertröm S,Brahme A

更新日期：1993-07-01 00:00:00

abstract：:The physical factors that govern 2D and 3D imaging performance may be understood from quantitative analysis of the spatial-frequency-dependent signal and noise transfer characteristics [e.g., modulation transfer function (MTF), noise-power spectrum (NPS), detective quantum efficiency (DQE), and noise-equivalent quanta...

journal_title：Medical physics

authors： Tward DJ,Siewerdsen JH

更新日期：2008-12-01 00:00:00

abstract：:System modeling is used to investigate the effect of various system parameters on the image quality in CCD-based x-ray imaging systems. The systems considered consist of a typical phosphor-based scintillating screen coupled to a CCD through lens or fiberoptic taper. Two applications, chest radiography and mammography,...

journal_title：Medical physics

authors： Hejazi S,Trauernicht DP

更新日期：1997-02-01 00:00:00

abstract：:A double-mirror multilayer monochromator was developed for the purpose of irradiating live cell cultures at the Synchrotron Radiation Center, University of Wisconsin-Madison. The monochromator is designed for the soft x-ray region with photon energies between 270 and 2400 eV. Multilayer mirrors with 55 bilayers of W/C...

journal_title：Medical physics

authors： MacKay JF,Pearson DW,Nelms BE,DeLuca PM Jr,Gould MN,Lagally MG

更新日期：1998-05-01 00:00:00

abstract：PURPOSE:The focus of this work was the demonstration and validation of VirtuaLinac with clinical photon beams and to investigate the implementation of low-Z targets in a TrueBeam linear accelerator (Linac) using Monte Carlo modeling. METHODS:VirtuaLinac, a cloud based web application utilizing Geant4 Monte Carlo code,...

journal_title：Medical physics

authors： Parsons D,Robar JL,Sawkey D

更新日期：2014-02-01 00:00:00

abstract：:Postoperative beta-irradiation after pterygium excision has been considered a valuable therapeutic procedure to reduce the recurrence rate. Recently, it was reported that beta-irradiation also substantially reduced the risk of surgical failure after glaucoma surgery. Pure beta-irradiation using a 90Sr/Y applicator has...

journal_title：Medical physics

authors： Park YK,Ye SJ,Kim IH,Wee WR,Kim MK,Han HS,Son KJ,Park UJ

更新日期：2008-05-01 00:00:00

abstract：PURPOSE:Integrating a linac with a magnetic resonance imager (MRI) will revolutionize the accuracy of external beam radiation treatments. Irradiating in the presence of a strong magnetic field, however, will modify the dose distribution. These dose modifications have been investigated previously, mainly using Monte Car...

journal_title：Medical physics

authors： Ghila A,Steciw S,Fallone BG,Rathee S

更新日期：2017-09-01 00:00:00

abstract：:It is shown that predictions can be made of scatter-to-primary ratios for a variety of mammographic configurations. The different configurations can be produced by changes in source-detector distance; source-phantom distance; air gap; photon energy; phantom composition, thickness, and cross-sectional area. A detailed ...

journal_title：Medical physics

authors： Bernstein H,Muntz EP

更新日期：1986-11-01 00:00:00

abstract：PURPOSE:Respiratory motion in the chest region during single photon emission computed tomography (SPECT) is a major degrading factor that reduces the accuracy of image quantification. This effect is more notable when the tumor is very small, or the spatial resolution of the imaging system is less than the respiratory m...

journal_title：Medical physics

authors： Naseri M,Rajabi H,Wang J,Abbasi M,Kalantari F

更新日期：2019-11-01 00:00:00

abstract：PURPOSE:For almost four decades bead and wire ramps have been used in the evaluation of slice width as part of QA testing for CT scanners. While each of these approaches have been recognized and accepted as reliable, in this paper we investigate the differences, advantages and limitations of these tools. Moreover, we s...

journal_title：Medical physics

authors： Marteinsdóttir M,Olafsdottir H,Fredriksson J,Andresson A,Healy A,Kristbjornsson A,Kristinsson S,Levy J,Goodenough D

更新日期：2012-06-01 00:00:00

abstract：:The attenuating properties of several types of lead (Pb)-based and non-Pb radiation shielding materials were studied and a correlation was made of radiation attenuation, materials properties, calculated spectra and ambient dose equivalent. Utilizing the well-characterized x-ray and gamma ray beams at the National Rese...

journal_title：Medical physics

authors： McCaffrey JP,Shen H,Downton B,Mainegra-Hing E

更新日期：2007-02-01 00:00:00

abstract：:During our routine calibration of a Varian Clinac-20 linear accelerator, the absorbed dose for a fixed monitor unit (mu) was found to decrease with increasing dose rate. Between dose rates of 100 and 500 mu/min, there was up to 20% difference in absorbed dose for a 20-MeV electron beam. The cause of this problem was a...

journal_title：Medical physics

authors： Cheng PC,Kubo H

更新日期：1988-09-01 00:00:00

abstract：PURPOSE:The purpose of this study was to describe and evaluate methods for calculating a megavoltage computed tomography (MVCT)-derived MR hardware attenuation map (μ-map) and dual-energy CT (DECT) for 511 keV photons. METHODS:Phantom measurements were acquired on a whole-body hybrid PET/MRI system, using a four-chann...

journal_title：Medical physics

authors： Patrick JC,Terry Thompson R,So A,Butler J,Faul D,Stodilka RZ,Yartsev S,Prato FS,Gaede S

更新日期：2017-09-01 00:00:00

abstract：PURPOSE:Colon cancer is a major public health problem due to its high disease rate and death toll worldwide. The use of FTIR microscopy in the field of cancer diagnosis has become attractive over the past 20 years. In the present study, the authors investigated the potential of FTIR microscopy to define spectral change...

journal_title：Medical physics

authors： Zwielly A,Mordechai S,Sinielnikov I,Salman A,Bogomolny E,Argov S

更新日期：2010-03-01 00:00:00

abstract：:An anthropomorphic 1H MRS head phantom has been developed which mimics the in vivo structure, metabolite concentrations, and relaxation times (for both water and metabolites) of human brain tissue. Different brain regions and two tumor types, fluid-containing ventricles, and air-filled sinus, and subcutaneous fat are ...

journal_title：Medical physics

authors： Rice JR,Milbrandt RH,Madsen EL,Frank GR,Boote EJ,Blechinger JC

更新日期：1998-07-01 00:00:00

abstract：PURPOSE:To develop a probabilistic treatment planning (PTP) method which is robust to systematic patient setup errors and to compare PTP plans with plans generated using a planning target volume (PTV) margin optimized to give the same target coverage probability as the PTP plan. METHODS:Plans adhering to the RTOG-0126...

journal_title：Medical physics

authors： Moore JA,Gordon JJ,Anscher M,Silva J,Siebers JV

更新日期：2012-02-01 00:00:00

abstract：:Adaptive histogram equalization techniques are known to be effective for the enhancement of contrast in portal images acquired during radiotherapy treatments. A significant drawback is the loss of definition on the edges of the treatment field. Analysis of this problem shows that it can be remedied by separating the t...

journal_title：Medical physics

authors： Leszczynski KW,Shalev S,Cosby NS

更新日期：1992-05-01 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

authors： Liu X,Shaw CC

更新日期：2007-07-01 00:00:00

abstract：:The photon spectra in vacuum around four types of 192Ir HDR brachytherapy sources are calculated using the Monte Carlo code EGS4 and the most recent spectral information on 192Ir decay. The air-kerma strengths per unit activity are calculated based on the photon fluence around a bare 192Ir source and around each of fo...

journal_title：Medical physics

authors： Borg J,Rogers DW

更新日期：1999-11-01 00:00:00

abstract：PURPOSE:We describe the acceptance testing, commissioning, periodic quality assurance, and workflow procedures developed for the first clinically implemented magnetic resonance imaging-guided radiation therapy (MR-IGRT) system for real-time tracking and beam control. METHODS:The system utilizes real-time cine imaging ...

journal_title：Medical physics

authors： Green OL,Rankine LJ,Cai B,Curcuru A,Kashani R,Rodriguez V,Li HH,Parikh PJ,Robinson CG,Olsen JR,Mutic S,Goddu SM,Santanam L

更新日期：2018-05-28 00:00:00

abstract：PURPOSE:To reduce the potential of late toxicity (tissue necrosis and cognitive function loss) from brain radiotherapy, we studied a novel planning technique for MLC-equipped linear accelerators (LINACS) that reduces the high doses delivered outside the PTV, enhancing radiation dose conformity. METHODS:The feasibility...

journal_title：Medical physics

authors： Yang W,Sandler H,Fraass B

更新日期：2012-06-01 00:00:00

abstract：:Current generation electronic portal imaging devices (EPID) contain a 1.0 mm copper conversion plate to increase detection efficiency of a therapeutic megavoltage spectrum. When using these EPIDs for low-Z target imaging, the conversion plate largely attenuates the large populations of diagnostic energy photons, there...

journal_title：Medical physics

authors： Parsons D,Robar JL

更新日期：2012-07-01 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

authors： Li J,Lu B,Yan G,Huang Y,Liu C

更新日期：2012-06-01 00:00:00

abstract：:Part III (oral exam) is the final part of ABR board exam for Diagnostic Medical Physics. In this exam, each of five oral examiners questions the candidate in each of five question categories. Oral exam has unique challenges to the candidate compared with the written exams. The candidate is expected to have not only ad...

journal_title：Medical physics

authors： Leng S,Chen L,Shu Y,McCollough C

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:Intraoperative electron radiation therapy (IOERT) involves the delivery of a high radiation dose during tumor resection in a shorter time than other radiation techniques, thus improving local control of tumors. However, a linear accelerator device is needed to produce the beam safely. Mobile linear accelerators...

journal_title：Medical physics

authors： Marinetto E,Victores JG,García-Sevilla M,Muñoz M,Calvo FÁ,Balaguer C,Desco M,Pascau J

更新日期：2017-10-01 00:00:00

abstract：PURPOSE:Dual-energy computed tomography and dual-energy cone-beam computed tomography (DE-CBCT) are promising modalities for applications ranging from vascular to breast, renal, hepatic, and musculoskeletal imaging. Accordingly, the optimization of imaging techniques for such applications would benefit significantly fr...

journal_title：Medical physics

authors： Gang GJ,Zbijewski W,Webster Stayman J,Siewerdsen JH

更新日期：2012-08-01 00:00:00

abstract：:In a practical classifier design problem, the true population is generally unknown and the available sample is finite-sized. A common approach is to use a resampling technique to estimate the performance of the classifier that will be trained with the available sample. We conducted a Monte Carlo simulation study to co...

journal_title：Medical physics

authors： Sahiner B,Chan HP,Hadjiiski L

更新日期：2008-04-01 00:00:00

abstract：:The relative sensitivity of the half-value layer (HVL) method as a quality index for megavoltage x-ray beams is examined by theoretical calculation and experimental measurements for 4-, 6-, 10-, and 25-MV x-ray beams. It is shown that lower atomic number materials are more sensitive to beam quality changes than higher...

journal_title：Medical physics

authors： Meli JA,Nath R

更新日期：1985-01-01 00:00:00

abstract：:We report on some extensions and further developments of a well-known microcalcification detection algorithm based on adaptive noise equalization. Tissue equivalent phantom images with and without labeled microcalcifications were subjected to this algorithm, and analyses of results revealed some shortcomings in the ap...

journal_title：Medical physics

authors： Gürün OO,Fatouros PP,Kuhn GM,de Paredes ES

更新日期：2001-04-01 00:00:00