Dose in the buildup region outside the primary beam.

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：PURPOSE:A prototype in-house program was developed to assist deriving image guidance shifts clinically using our 4DCT method for lung SBRT. METHODS:Our in-house prototype program was implemented in MATLAB. The 4D DICOM CT dataset of interest is imported by the program from AW and subsequently accepts input from the us...

journal_title：Medical physics

authors： Wang B,Sarkar V,Busselberg C,Rassiah-Szegedi P,Zhao H,Huang Y,Szegedi M,Salter B

更新日期：2012-06-01 00:00:00

abstract：:Noise, partial volume (PV) effect, and image-intensity inhomogeneity render a challenging task for segmentation of brain magnetic resonance (MR) images. Most of the current MR image segmentation methods focus on only one or two of the above-mentioned effects. The objective of this paper is to propose a unified framewo...

journal_title：Medical physics

authors： Li X,Li L,Lu H,Liang Z

更新日期：2005-07-01 00:00:00

abstract：:We designed a novel force/torque moment transducer with six degrees of freedom. This new sensor is used for measuring the forces and torque moments exerted by static magnetic resonance imaging (MRI) fields on various medical implants, instruments, and ballistic shell fragments. To determine the location of strongest e...

journal_title：Medical physics

authors： Planert J,Modler H,Vosshenrich R

更新日期：1996-06-01 00:00:00

abstract：:This investigation contains the results of exposure measurements on two types of clinical I-125 seeds: a model 6702 no-marker seed, and a model 6711 silver wire seed. Measurements were made locally with a parallel-plate mammography chamber, traceable to the National Bureau of Standards (NBS) calibration. The same seed...

journal_title：Medical physics

authors： Kubo H

更新日期：1985-03-01 00:00:00

abstract：PURPOSE:To validate a delivery quality assurance (DQA) protocol for tomotherapy based on the measurement of the leaf open times (LOTs). In addition, to show the correlation between the mean relative LOT discrepancy and the dose deviation in the planning target volume (PTV). MATERIALS AND METHODS:We used a LOT measurem...

journal_title：Medical physics

authors： Schopfer M,Bochud FO,Bourhis J,Moeckli R

更新日期：2020-09-01 00:00:00

abstract：PURPOSE:Stereotactic ablative body radiotherapy (SABR) for lung patients can be performed with volumetric-modulated arc therapy (VMAT) plans using off-axis target geometry to allow treatment in their CBCT verified position. For patient-specific quality assurance measurements using the PTW Octavius 4D phantom (PTW, Frei...

journal_title：Medical physics

authors： Jeevanandam P,Agnew CE,Irvine DM,McGarry CK

更新日期：2018-04-01 00:00:00

abstract：PURPOSE:To investigate the geometry dependence of the detector response function (DRF) of three commonly used scanning ionization chambers and its impact on a convolution-based method to address the volume averaging effect (VAE). METHODS:A convolution-based approach has been proposed recently to address the ionization...

journal_title：Medical physics

authors： Barraclough B,Li JG,Lebron S,Fan Q,Liu C,Yan G

更新日期：2016-05-01 00:00:00

abstract：:A restricted angular scattering model for electron penetration in dense media is presented. In the model, the Fermi-Eyges transport equation is modified through the addition of an extra term which may be interpreted as representing an apparent force opposing the scattering of electrons into wider angles. The introduct...

journal_title：Medical physics

authors： McLellan J,Sandison GA,Papiez L,Huda W

更新日期：1991-01-01 00:00:00

abstract：PURPOSE:Episcleral eye plaque brachytherapy has been utilized in the treatment of intra-ocular malignancies, delivering large prescription doses to the apex of the tumor. Advances in dose calculation and image guidance, via calibrated fundus images, enable localization of the tumor and determination of dose to the macu...

journal_title：Medical physics

authors： Guida K,Niermann K,Malcolm A,Sternberg P,Munn G,Coffey C

更新日期：2012-06-01 00:00:00

abstract：:A test device which can indirectly measure the performance of an automatic exposure control system and which offers the potential to reduce the time and film requirements for such tests has been evaluated. Evaluation results demonstrate that the device can successfully predict image optical density to within +/- 0.10 ...

journal_title：Medical physics

authors： Rossi RP

更新日期：1994-01-01 00:00:00

abstract：PURPOSE:To find an upper bound on the maximum dose reduction possible for any reconstruction algorithm, analytic or iterative, that result from the inclusion of the data statistics. The authors do not analyze noise reduction possible from prior knowledge or assumptions about the object. METHODS:The authors examined th...

journal_title：Medical physics

authors： Hsieh SS,Chesler DA,Fleischmann D,Pelc NJ

更新日期：2016-03-01 00:00:00

abstract：PURPOSE:We have recently developed a dynamic tumor tracking irradiation system using Vero4DRT (MHI-Tm2 000). It is needed to create a 4D correlation model between a fiducial marker implanted near a tumor and an external surrogate as a function of time by continuously acquiring both fluoroscopy images and external surro...

journal_title：Medical physics

authors： Shiinoki T,Sawada A,Ishihara Y,Miyabe Y,Fujimoto T,Nakai T,Matsuo Y,Mizowaki T,Kokubo M,Hiraoka M

更新日期：2012-06-01 00:00:00

abstract：:Like Medical Physics, Imaging Informatics encompasses concepts touching every aspect of the imaging chain from image creation, acquisition, management and archival, to image processing, analysis, display and interpretation. The two disciplines are in fact quite complementary, with similar goals to improve the quality ...

journal_title：Medical physics

authors： Andriole K

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:To study the impact of target geometrical and linac operational parameters, such as target material and thickness, electron beam size, repetition rate, and mean current on the ability of the radiotherapy treatment head to deliver high-dose-rate x-ray irradiation in the context of novel linear accelerators capab...

journal_title：Medical physics

authors： Wang J,Trovati S,Borchard PM,Loo BW Jr,Maxim PG,Fahrig R

更新日期：2017-12-01 00:00:00

abstract：PURPOSE:Intensity Modulated Neutron Radiotherapy (IMNRT) has been commissioned for clinical use. The number of allowable segments in IMNRT plans is limited by MLC speed. Quality and deliverability of static IMNRT treatment plans using the TG-119 test suite were evaluated to establish guidelines for the number of segmen...

journal_title：Medical physics

authors： Spink R,Burmeister J,Bossenberger T,Snyder M

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:Dynamic 18 F-FDG PET allows quantitative estimation of cerebral glucose metabolism both at the regional and local (voxel) level. Although sensitive to noise and highly computationally expensive, nonlinear least-squares (NLS) optimization stands as the reference approach for the estimation of the kinetic model p...

journal_title：Medical physics

authors： Ben Bouallègue F,Vauchot F,Mariano-Goulart D

更新日期：2019-03-01 00:00:00

abstract：PURPOSE:A commonly used beam quality index (Q) for high-energy photon beams is the tissue phantom ratio (TPR20,10) for a square field of 10 x 10 cm2 and SDD of 100 cm. On some specialized radiotherapy treatment equipment such a reference collimator setting is not achievable. Likewise a flat beam profile, not explicitly...

journal_title：Medical physics

authors： Sauer OA

更新日期：2009-09-01 00:00:00

abstract：:A novel iterative penalized likelihood algorithm with evolutionary components for the optimization of beamlet fluences for intensity modulated radiation therapy (IMRT) is presented. This algorithm is designed to be flexible in terms of the objective function and automatically escalates dose, as long as the objective f...

journal_title：Medical physics

authors： Baydush AH,Marks LB,Das SK

更新日期：2004-08-01 00:00:00

abstract：PURPOSE:New preclinical image-guided irradiators and treatment planning systems represent a huge progress in radiobiology. Nevertheless, quality control of preclinical treatments is not as advanced as in clinical radiotherapy and in vivo dosimetry is less developed. In this study, we evaluate the use of a scintillating...

journal_title：Medical physics

authors： Le Deroff C,Pérès EA,Ledoux X,Toutain J,Frelin-Labalme AM

更新日期：2020-01-01 00:00:00

abstract：PURPOSE:To develop an automatic knot placement algorithm to enable the use of NonUniform Rational B-Splines (NURBS) in deformable image registration. METHODS:The authors developed a two-step approach to fit a known displacement vector field (DVF). An initial fit was made with uniform knot spacing. The error generated ...

journal_title：Medical physics

authors： Jacobson TJ,Murphy MJ

更新日期：2011-08-01 00:00:00

abstract：:Manganese (Mn) is an essential nutrient for growth and development. Unfortunately, overexposure can lead to neurological damage, which is manifested as a movement disorder marked by tremors. Preclinical symptoms have been found in populations occupationally exposed to the element, and it is suggested that in late stag...

journal_title：Medical physics

authors： Arnold ML,McNeill FE,Stronach IM,Pejovic-Milic A,Chettle DR,Waker A

更新日期：2002-11-01 00:00:00

abstract：:This paper is concerned with the proposed Birmingham accelerator-based epithermal neutron beam for boron neutron capture therapy (BNCT). In particular, the option of producing a therapy beam at an orthogonal direction to the incoming protons is considered. Monte Carlo radiation transport simulations, both with and wit...

journal_title：Medical physics

authors： Allen DA,Beynon TD,Green S

更新日期：1999-01-01 00:00:00

abstract：:In this work, the authors have evaluated ten different ionization chambers for the relative dosimetry of kilovoltage x-ray beams in the energy range of 50-280 kVp. Percentage depth doses in water and relative detector response (in Solid Water and in air) were measured for each of the x-ray beams studied using a number...

journal_title：Medical physics

authors： Hill R,Mo Z,Haque M,Baldock C

更新日期：2009-09-01 00:00:00

abstract：:We designed a questionnaire to be filled out by the physicist at the time of planning treatment with the aid of a computer in order to assess what was learned during the course of the planning session. We analyzed the results to gauge the impact of the 70 treatment planning sessions conducted during the one month peri...

journal_title：Medical physics

authors： Doppke KP,Goitein M

更新日期：1988-03-01 00:00:00

abstract：PURPOSE:The most common metric for comparing measured to calculated dose, such as for pretreatment quality assurance of intensity-modulated photon fields, is a pass rate (%) generated using percent difference (%Diff), distance-to-agreement (DTA), or some combination of the two (e.g., gamma evaluation). For many dosimet...

journal_title：Medical physics

authors： Bailey DW,Nelms BE,Attwood K,Kumaraswamy L,Podgorsak MB

更新日期：2011-11-01 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：:Convolution/superposition software has been used to produce a library of photon pencil beam dose matrices. This library of pencil beams is designed to serve as a tool for both education and investigation in the field of radiotherapy optimization. The elegance of this pencil beam model stems from its cylindrical symmet...

journal_title：Medical physics

authors： Shepard DM,Olivera G,Angelos L,Sauer O,Reckwerdt P,Mackie TR

更新日期：1999-07-01 00:00:00

abstract：:Myocardial beta adrenergic receptor (beta-AR) concentration can substantially decrease in congestive heart failure and significantly increase in chronic volume overload, such as in severe aortic valve regurgitation. Positron emission tomography (PET) with an appropriate ligand-receptor model can be used for noninvasiv...

journal_title：Medical physics

authors： Salinas C,Muzic RF Jr,Ernsberger P,Saidel GM

更新日期：2007-01-01 00:00:00

abstract：PURPOSE:The present study was conducted to investigate salivary iodine kinetics and dosimetry during repeated courses of radioiodine ((131)I) therapy for differentiated thyroid cancer (DTC). Such data could provide a better understanding of the mechanisms of (131)I induced salivary toxicity and help to develop appropri...

journal_title：Medical physics

authors： Liu B,Huang R,Kuang A,Zhao Z,Zeng Y,Wang J,Tian R

更新日期：2011-10-01 00:00:00