A numerical study of the acoustic radiation due to eddy current-cryostat interactions.

abstract：PURPOSE:Computerized liver extraction from hepatic CT images is challenging because the liver often abuts other organs of a similar density. The purpose of this study was to develop a computer-aided measurement of liver volumes in hepatic CT. METHODS:The authors developed a computerized liver extraction scheme based o...

journal_title：Medical physics

authors： Suzuki K,Kohlbrenner R,Epstein ML,Obajuluwa AM,Xu J,Hori M

更新日期：2010-05-01 00:00:00

abstract：PURPOSE:This article presents a new reconstruction method for 3D imaging using a multiple 360 degrees circular orbit cone beam CT system, specifically a way to combine 3D volumes reconstructed with each orbit. The main goal is to improve the noise performance in the combined image while avoiding cone beam artifacts. M...

journal_title：Medical physics

authors： Baek J,Pelc NJ

更新日期：2010-10-01 00:00:00

abstract：:The customization of brachytherapy dose distributions for gynecologic malignancies is limited by the spatial positioning of the applicators. We tested the hypothesis that applicator-guided intensity modulated radiation therapy (AGIMRT) has the potential to deliver highly conformal dose distributions to cervical tumors...

journal_title：Medical physics

authors： Wahab SH,Malyapa RS,Mutic S,Grigsby PW,Deasy JO,Miller TR,Zoberi I,Low DA

更新日期：2004-04-01 00:00:00

abstract：PURPOSE:Computed tomography (CT) is one of the most used imaging modalities for imaging both symptomatic and asymptomatic patients. However, because of the high demand for lower radiation dose during CT scans, the reconstructed image can suffer from noise and artifacts due to the trade-off between the image quality and...

journal_title：Medical physics

authors： Kim K,El Fakhri G,Li Q

更新日期：2017-10-01 00:00:00

abstract：PURPOSE:To characterize the modulation transfer function (MTF) of proton/carbon radiography using Monte Carlo simulations. To assess the spatial resolution of proton/carbon radiographic imaging. METHODS:A phantom was specifically modeled with inserts composed of two materials with three different densities of bone and...

journal_title：Medical physics

authors： Seco J,Oumano M,Depauw N,Dias MF,Teixeira RP,Spadea MF

更新日期：2013-09-01 00:00:00

abstract：PURPOSE:The purpose of the paper was to use a virtual phantom to identify a set of radiomic features from T1-weighted and T2-weighted magnetic resonance imaging (MRI) of the brain which is stable to variations in image acquisition parameters and to evaluate the effect of image preprocessing on radiomic features stabili...

journal_title：Medical physics

authors： Bologna M,Corino V,Mainardi L

更新日期：2019-11-01 00:00:00

abstract：PURPOSE:To investigate the critical structure sparing achievable by biological optimization for modulated volumetric arc (VMAT) of head and neck (H&N) cancer. METHODS:Ten H&N VMAT patients who were originally planned and treated with simultaneous integrated boost technique using dose-volume based optimization, were se...

journal_title：Medical physics

authors： Dogan N,Wu Y

更新日期：2012-06-01 00:00:00

abstract：:Separation of water from fat tissues in magnetic resonance imaging is important for many applications because signals from fat tissues often interfere with diagnoses that are usually based on water signal characteristics. Water and fat can be separated with images acquired at different echo time shifts. The three-poin...

journal_title：Medical physics

authors： Wen Z,Reeder SB,Pineda AR,Pelc NJ

更新日期：2008-08-01 00:00:00

abstract：PURPOSE:Volumetric x-ray microcomputed tomography (CT) can be employed in a variety of quantitative research applications such as image-guided interventions or characterization of medical devices. To ensure the highest geometric fidelity of images for these applications, a phantom and image processing algorithm have be...

journal_title：Medical physics

authors： Waring CS,Bax JS,Samarabandu A,Holdsworth DW,Fenster A,Lacefield JC

更新日期：2012-10-01 00:00:00

abstract：PURPOSE:Sterile radiation reduction gloves have been widely used in the past decade to provide modest decreases in operator hand dose when the hands are placed in the field of view (FOV). While multiple publications have quantified the potential dose reduction from the use of such gloves, possible effects on the patien...

journal_title：Medical physics

authors： Pasciak A,Neveu M,Sriharan A,Balius A,Jones A

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:The Acuros XB (AXB) Advanced Dose algorithm (Varian Medical Systems) represents a dramatic shift in clinical photon dose calculation methodology from pencil-beam superposition/convolution methods. Early studies evaluating the accuracy of the algorithm in lung have found good agreement with both measurement and ...

journal_title：Medical physics

authors： Bush K,Wang L,Mok E

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:The determination of absorbed dose to water from external beam radiotherapy using radiation detectors is currently rooted in calibration protocols that do not account for modulations encountered in patient-specific deliveries. Detector response in composite clinical fields has not been extensively studied due t...

journal_title：Medical physics

authors： Desai VK,Labby ZE,Hyun MA,DeWerd LA,Culberson WS

更新日期：2019-02-01 00:00:00

abstract：:The aim of this work was to test the suitability of a PTW diamond detector for nonreference condition dosimetry in photon beams of different energy (6 and 25 MV) and field size (from 2.6 cm x 2.6 cm to 10 cm x 10 cm). Diamond behavior was compared to that of a Scanditronix p-type silicon diode and a Scanditronix RK io...

journal_title：Medical physics

authors： Bucciolini M,Buonamici FB,Mazzocchi S,De Angelis C,Onori S,Cirrone GA

更新日期：2003-08-01 00:00:00

abstract：PURPOSE:To objectively characterize the performance of the gemstone spectral imaging (GSI) mode of GE CT750 HD scanner from a user's perspective. METHODS:A regular scan protocol that approximates the adult abdomen scan protocol frequently used in the authors' institute was selected as the baseline, and a GSI protocol ...

journal_title：Medical physics

authors： Zhang D,Li X,Liu B

更新日期：2011-03-01 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：:Machine outputs, peak scatter factors, and central axis percentage depth dose distributions were measured for various phantom sizes in large radiation fields produced at extended distances by cobalt, 6-MV, and 10-MV photon beams. The results can be applied to practical total body irradiation procedures which usually i...

journal_title：Medical physics

authors： Podgorsak EB,Pla C,Evans MD,Pla M

更新日期：1985-09-01 00:00:00

abstract：:This study evaluates the effects of respiratory motion on breast radiotherapy delivered using segmented multileaf collimator (SMLC) intensity modulation. An anthropomorphic breast phantom was constructed of polystyrene plates between which radiographic films were inserted. The phantom was mounted on a moving platform ...

journal_title：Medical physics

authors： Liu Q,McDermott P,Burmeister J

更新日期：2007-01-01 00:00:00

abstract：PURPOSE:Transcranial focused ultrasound is an emerging therapeutic modality that can be used to perform noninvasive neurosurgical procedures. The current clinical transcranial phased array operates at 650 kHz, however the development of a higher frequency array would enable more precision, while reducing the risk of st...

journal_title：Medical physics

authors： Pajek D,Hynynen K

更新日期：2013-12-01 00:00:00

abstract：PURPOSE:Micro-CT is widely used for small animal imaging in preclinical studies of cardiopulmonary disease, but further development is needed to improve spatial resolution, temporal resolution, and material contrast. We present a technique for visualizing the changing distribution of iodine in the cardiac cycle with du...

journal_title：Medical physics

authors： Johnston SM,Johnson GA,Badea CT

更新日期：2012-08-01 00:00:00

abstract：:The purpose of this work is to compare the efficacy of mathematical models in predicting the occurrence of radiotherapy-induced left ventricular perfusion defects assessed using single-photon emission computed tomography (SPECT). The basis of this study is data from 73 left-sided breast/ chestwall patients treated wit...

journal_title：Medical physics

authors： Das SK,Baydush AH,Zhou S,Miften M,Yu X,Craciunescu O,Oldham M,Light K,Wong T,Blazing M,Borges-Neto S,Dewhirst MW,Marks LB

更新日期：2005-01-01 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

authors： Catuzzo P,Zenone F,Aimonetto S,Peruzzo A,Casanova Borca V,Pasquino M,Franco P,La Porta MR,Ricardi U,Tofani S

更新日期：2012-07-01 00:00:00

abstract：PURPOSE:Quantification of body composition plays an important role in many clinical and research applications. Radiologic imaging techniques such as Dual-energy X-ray absorptiometry (DXA), magnetic resonance imaging (MRI), and computed tomography (CT) imaging make accurate quantification of the body composition possibl...

journal_title：Medical physics

authors： Liu T,Udupa JK,Miao Q,Tong Y,Torigian DA

更新日期：2019-03-01 00:00:00

abstract：:In many of brachytherapy procedures, a large amount of radioactive sources are used to deliver desired doses to the target volume. It is both the federal regulation recommendation (U.S. Nuclear Regulatory Commission, 10 CFR 35.432) and recommendations of the American Association of Physicists in Medicine (AAPM) [Kutch...

journal_title：Medical physics

authors： Yue NJ,Haffty BG,Yue J

更新日期：2007-06-01 00:00:00

abstract：PURPOSE:The dosimetric advantage of particle therapy comes with a much higher infrastructure investment and operation costs. Increasing patient throughput is a key factor to manage operation costs. We investigate the impact of variable beam spot sizes on treatment time and discuss the tradeoffs involved. METHODS:The f...

journal_title：Medical physics

authors： Riofrio D,Sellner S,Cabal G,Keyes R,Holzscheiter M,Jaekel O,Luan S

更新日期：2012-06-01 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

authors： Yamashita Y,Maki A,Koizumi H

更新日期：2001-06-01 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

authors： Wiersma RD,Mao W,Xing L

更新日期：2008-04-01 00:00:00

abstract：PURPOSE:Contrast-enhanced imaging of the breast is frequently used in breast MRI and has recently become more common in mammography. The purpose of this study was to make single-scan contrast-enhanced imaging feasible for photon-counting breast CT (pcBCT) and to assess the spectral performance of a pcBCT scanner by eva...

journal_title：Medical physics

authors： Ruth V,Kolditz D,Steiding C,Kalender WA

更新日期：2020-07-01 00:00:00

abstract：:We propose a new method based on statistical analysis technique to determine the minimum setup distance of a well chamber used in the calibration of 192Ir high dose rate (HDR). The chamber should be placed at least this distance away from any wall or from the floor in order to mitigate the effect of scatter. Three dif...

journal_title：Medical physics

authors： Chang L,Ho SY,Chui CS,Lee JH,Du YC,Chen T

更新日期：2008-06-01 00:00:00

abstract：PURPOSE:When designing a collimation system for pencil beam spot scanning proton therapy, a decision must be made whether or not to rotate, or focus, the collimator to match beamlet deflection as a function of off-axis distance. If the collimator is not focused, the beamlet shape and fluence will vary as a function of ...

journal_title：Medical physics

authors： Geoghegan TJ,Nelson NP,Flynn RT,Hill PM,Rana S,Hyer DE

更新日期：2020-07-01 00:00:00

abstract：PURPOSE:The segmentation accuracy of medical images was improved by increasing the number of training samples using a local image warping technique. The performance of the proposed method was evaluated in the segmentation of breast masses, prostate and brain tumors, and lung nodules. METHODS:We propose a simple data a...

journal_title：Medical physics

authors： Liu H,Cao H,Song E,Ma G,Xu X,Jin R,Liu T,Liu L,Liu D,Hung CC

更新日期：2020-12-10 00:00:00