Design and optimization of large area thin-film CdTe detector for radiation therapy imaging applications.

abstract：:We applied Monte Carlo methods for the simulation of x-ray scattering in water phantoms. The phantom thickness was varied from 5 to 20 cm, and the monoenergetic incident x rays were varied from 15 to 100 keV. Eight screen pairs and a total absorption system were used as x-ray receptors. We determined the angular, spec...

journal_title：Medical physics

authors： Chan HP,Doi K

更新日期：1985-03-01 00:00:00

abstract：:The authors describe a method for directly digitizing optical images with a photostimulable phosphor (PSP) system. A PSP plate is initially charged with an exposure to a uniform x-ray field, and is then exposed to an optical image which discharges the plate in relation to the amount of incident light. Two applications...

journal_title：Medical physics

authors： Dobbins JT 3rd,Chotas HG,Benveniste H

更新日期：1992-07-01 00:00:00

abstract：PURPOSE:Photoacoustic imaging has proven to be able to detect vascularization-driven optical absorption contrast associated with tumors. In order to detect breast tumors located a few centimeter deep in tissue, a sensitive ultrasound detector is of crucial importance for photoacoustic mammography. Further, because the ...

journal_title：Medical physics

authors： Xia W,Piras D,van Hespen JC,van Veldhoven S,Prins C,van Leeuwen TG,Steenbergen W,Manohar S

更新日期：2013-03-01 00:00:00

abstract：PURPOSE:The purpose of this study was to assess, using an anthropomorphic digital phantom, the accuracy of algorithms in registering precontrast and contrast-enhanced computed tomography (CT) chest images for generation of iodine maps of the pulmonary parenchyma via temporal subtraction. MATERIALS AND METHODS:The XCAT...

journal_title：Medical physics

authors： Grob D,Oostveen L,Rühaak J,Heldmann S,Mohr B,Michielsen K,Dorn S,Prokop M,Kachelrieβ M,Brink M,Sechopoulos I

更新日期：2019-05-01 00:00:00

abstract：PURPOSE:The appearance of parenchymal∕stromal patterns in mammography have been characterized as having a Wiener power spectrum with an inverse power-law shape described by the exponential parameter, β. The amount of fibroglandular tissue, which can be quantified in terms of volumetric breast density (VBD), influences ...

journal_title：Medical physics

authors： Mainprize JG,Tyson AH,Yaffe MJ

更新日期：2012-08-01 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：:A photon transport algorithm for fully three-dimensional radiotherapy treatment planning has been developed based on the discrete ordinates (SN) solution of the Boltzmann equation. The algorithm is characterized by orthogonal adaptive meshes, which place additional points where large gradients occur and a procedure to...

journal_title：Medical physics

authors： Yuan J,Jette D,Chen W

更新日期：2008-09-01 00:00:00

abstract：PURPOSE:To demonstrate an objective approach to determining if a negative report from the Radiological Physics Center (RPC) of greater than 10% error is valid or has clinical significance. METHODS:The discrepancy involved the clinical activity (mgRaEq) of Cs-137 sources, some manufactured by 3M and some by Amersham. M...

journal_title：Medical physics

authors： Grant W 3rd,Mcgary J,Rosen I,Nitsch P,Davidson S

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:Helical tomotherapy is a complex delivery technique, integrating CT image guidance and intensity modulated radiotherapy in a single system. The integration of the CT detector ring on the gantry not only allows patient position verification but is also often used to perform various QA procedures. This convenienc...

journal_title：Medical physics

authors： Wong JH,Hardcastle N,Tomé WA,Bayliss A,Tolakanahalli R,Lerch ML,Petasecca M,Carolan M,Metcalfe P,Rosenfeld AB

更新日期：2011-04-01 00:00:00

abstract：PURPOSE:To characterize the radiation dose and three-dimensional (3D) imaging performance of a recently developed mobile, isocentric C-arm equipped with a flat-panel detector (FPD) for intraoperative cone-beam computed tomography (CBCT) (Cios Spin 3D, Siemens Healthineers) and to identify potential improvements in 3D i...

journal_title：Medical physics

authors： Sheth NM,De Silva T,Uneri A,Ketcha M,Han R,Vijayan R,Osgood GM,Siewerdsen JH

更新日期：2020-03-01 00:00:00

abstract：PURPOSE:The need for four-dimensional (4D) treatment planning becomes indispensable when it comes to radiation therapy for moving tumors in the thoracic and abdominal regions. The primary purpose of this study is to combine the actual breathing trace during each individual treatment fraction with the Linac's log file i...

journal_title：Medical physics

authors： Freislederer P,von Münchow A,Kamp F,Heinz C,Gerum S,Corradini S,Söhn M,Reiner M,Roeder F,Floca R,Alber M,Belka C,Parodi K

更新日期：2019-07-01 00:00:00

abstract：:It is well-known that the edge effect produced by phase contrast imaging results in the edge enhancement of x-ray images and thereby sharpens those images. It has recently been reported that phase contrast imaging using practical x-ray tubes with small focal spots has improved image sharpness as observed in the phase ...

journal_title：Medical physics

authors： Matsuo S,Katafuchi T,Tohyama K,Morishita J,Yamada K,Fujita H

更新日期：2005-08-01 00:00:00

abstract：:Up to the present, the majority of low contrast object evaluations performed on phantom images have been accomplished in a subjective fashion. This is mainly due to the time and effort required to manually measure each radiograph with a densitometer to obtain quantitative results. However, with the development of digi...

journal_title：Medical physics

authors： Kwan AL,Filipow LJ,Le LH

更新日期：2003-03-01 00:00:00

abstract：:In this article, the authors present a novel real-time cancer detection technique by using needle insertion forces in conjunction with patient-specific criteria during percutaneous interventions. Needle insertion experiments and pathological analysis were performed for developing a computer-aided detection (CAD) model...

journal_title：Medical physics

authors： Yan K,Li L,Joseph J,Rubens DR,Messing EM,Liao L,Yu Y

更新日期：2009-07-01 00:00:00

abstract：:A detailed Monte Carlo study of the PTW-diamond solid state detector response in megavoltage photon beams (60Co gamma rays to 25 MV x rays) has been performed with the EGS4 Monte Carlo Code. The sensitive volume of the diamond detector is a disk of diameter 4.4 mm and thickness 0.40 mm. The phantom material was water ...

journal_title：Medical physics

authors： Mobit PN,Sandison GA

更新日期：1999-11-01 00:00:00

abstract：PURPOSE:Radiation treatments are trending toward delivering higher doses per fraction under stereotactic radiosurgery and hypofractionated treatment regimens. There is a need for accurate 3D in vivo patient dose verification using electronic portal imaging device (EPID) measurements. This work presents a model-based te...

journal_title：Medical physics

authors： Van Uytven E,Van Beek T,McCowan PM,Chytyk-Praznik K,Greer PB,McCurdy BM

更新日期：2015-12-01 00:00:00

abstract：PURPOSE:Bone strength is the key factor impacting fracture risk. Assessment of bone strength from high-resolution (HR) images have largely relied on linear micro-finite element analysis (μFEA) even though failure always occurs beyond the yield point, which is outside the linear regime. Nonlinear μFEA may therefore be m...

journal_title：Medical physics

authors： Zhang N,Magland JF,Rajapakse CS,Bhagat YA,Wehrli FW

更新日期：2013-05-01 00:00:00

abstract：:Traditionally, short scan helical FDK algorithms have been implemented based on horizontal transaxial slices. However, not every point on the horizontal transaxial slice satisfies Tuy's condition for the corresponding (pi+fan angle) segment of helix, which means that some points on the horizontal slices are incomplete...

journal_title：Medical physics

authors： Hu J,Tam K,Qi J

更新日期：2005-06-01 00:00:00

abstract：:We proposed to use the prostate dose-volume factor (PDVF), derived from the dose-volume dataset of planning target volume (PTV) in prostate radiotherapy to evaluate treatment plans of prostate volumetric modulated arc therapy (VMAT) and intensity modulated radiotherapy (IMRT). To demonstrate plan evaluation using PDVF...

journal_title：Medical physics

authors： Chow J,Jiang R,Markel D

更新日期：2012-07-01 00:00:00

abstract：:The purposes of this research are to investigate the effectiveness of our novel image features for segmentation of anatomic regions such as the lungs and the mediastinum in chest radiographs and to develop an automatic computerized method for image processing. A total of 85 screening chest radiographs from Johns Hopki...

journal_title：Medical physics

authors： Tsujii O,Freedman MT,Mun SK

更新日期：1998-06-01 00:00:00

abstract：PURPOSE:Identification of calcifications and hemorrhages is essential for the etiological diagnosis of cerebral lesions. The purpose of this work was to develop a robust method for characterization of para- and diamagnetic intracerebral lesions based on clinical gradient-echo magnetic resonance phase data acquired at 1...

journal_title：Medical physics

authors： Schweser F,Deistung A,Lehr BW,Reichenbach JR

更新日期：2010-10-01 00:00:00

abstract：PURPOSE:Removal of the linear accelerator (linac) flattening filter enables a high rate of dose deposition with reduced treatment time. When used for megavoltage imaging, an unflat beam has reduced primary beam scatter resulting in sharper images. In fluoroscopic imaging mode, the unflat beam has higher photon count pe...

journal_title：Medical physics

authors： Christensen JD,Kirichenko A,Gayou O

更新日期：2013-08-01 00:00:00

abstract：:Radiation sensitive gels have been used as dosimeters for clinical dose verification of different radiation therapy modalities. However, the use of gels is not widespread, because careful techniques are required to achieve the dose precision and accuracy aimed for in clinical dose verification. Here, the introduction ...

journal_title：Medical physics

authors： Crescenti RA,Scheib SG,Schneider U,Gianolini S

更新日期：2007-04-01 00:00:00

abstract：:Ionization chambers of varying inside diameter have been used to investigate the penumbral region of 60Co, 6-MV, and 31-MV x-ray beams. Measurements were made in water at varying depths up to 25 cm for a square field of side length 10 cm. The dependence of the penumbral widths on both the inside diameter of the ioniza...

journal_title：Medical physics

authors： Dawson DJ,Schroeder NJ,Hoya JD

更新日期：1986-01-01 00:00:00

abstract：:We present a technique for semiautomated segmentation of human prostates using suprapubic ultrasound (US) images. In this approach, a speckle reducing anisotropic diffusion (SRAD) is applied to enhance the images and the instantaneous coefficient of variation (ICOV) is utilized for edge detection. Segmentation is acco...

journal_title：Medical physics

authors： Yu Y,Molloy JA,Acton ST

更新日期：2004-12-01 00:00:00

abstract：:In nuclear magnetic resonance (NMR) imaging by the zeugmatographic methods, there is a common and unified theoretical description. All forms of two-dimensional and three-dimensional imaging involve NMR data which trace various geometric representations, in reciprocal transform space, of the subject's spatially blurred...

journal_title：Medical physics

authors： King KF,Moran PR

更新日期：1984-01-01 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

authors： Xie Q,Ruan D

更新日期：2014-04-01 00:00:00

abstract：:The ability to control thermal drifts is essential in operating a calorimeter. We investigated a thermal enclosure, which envelops the calorimeter with temperature-regulated air, thus thermally isolating the calorimeter from the room. The desired temperature in the enclosure is controlled by a control circuit and a th...

journal_title：Medical physics

authors： Kubo H,Brown DE,Russell MD

更新日期：1985-05-01 00:00:00

abstract：PURPOSE:To simplify the often complex and user-dependent manual region of interest (ROI) selection process for head motion monitoring, an automatic ROI selection method was developed. METHODS:The automatic ROI selection algorithm calculated the displacements and velocities of 3D surface points between a temporally cor...

journal_title：Medical physics

authors： Kang HJ,Grelewicz Z,Wiersma RD

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:Small animal immobilization devices facilitate positioning of animals for reproducible imaging and accurate focal radiation therapy. In this study, the authors demonstrate the use of three-dimensional (3D) printing technology to fabricate a custom-designed mouse head restraint. The authors evaluate the accuracy...

journal_title：Medical physics

authors： Zarghami N,Jensen MD,Talluri S,Foster PJ,Chambers AF,Dick FA,Wong E

更新日期：2015-11-01 00:00:00