Numerical calculation of energy deposition by broad high-energy electron beams.

abstract：:Dual energy computed tomography (DECT) is currently a subject of extensive investigation. DECT is currently implemented using either a dual source scanner with high and low kVp data acquired from separate sources or a single source scanner with both high and low kVp data acquired in an alternating manner. Both methods...

journal_title：Physics in medicine and biology

authors： Szczykutowicz TP,Chen GH

更新日期：2010-11-07 00:00:00

abstract：:This study aims at developing an optimization strategy for photon-beam dosimetry in magnetic fields using ionization chambers. Similar to the familiar case in the absence of a magnetic field, detectors should be selected under the criterion that their measured 2D signal profiles M(x,y) approximate the absorbed dose to...

journal_title：Physics in medicine and biology

authors： Looe HK,Delfs B,Poppinga D,Harder D,Poppe B

更新日期：2018-03-29 00:00:00

abstract：:To investigate the profile measurement capabilities of an IBA-Dosimetry scintillation detector and to assess its feasibility for determining the low-intensity tails of pencil-beam scanning spots, the responses of the scintillation detector and Gafchromic EBT2 film to a 115 MeV proton spot were measured in-air at the i...

journal_title：Physics in medicine and biology

authors： Lin L,Ainsley CG,Mertens T,De Wilde O,Talla PT,McDonough JE

更新日期：2013-06-21 00:00:00

abstract：:Crucial to all cancer therapy modalities is a strong correlation between treatment and effect. Predictability of therapy success/failure allows for the optimization of treatment protocol and aids in the decision of whether additional treatment is necessary to prevent tumour progression. This work evaluated the relatio...

journal_title：Physics in medicine and biology

authors： Hrycushko BA,Ware S,Li S,Bao A

更新日期：2011-09-07 00:00:00

abstract：:Input functions required for positron emission tomography (PET) tracer kinetic modeling are often obtained from arterial blood. In some situations, using short-lived radiotracers, e.g. [(15)O]water, rapid sample handling is required. A method used at several facilities is to pump blood through a detector system at a c...

journal_title：Physics in medicine and biology

authors： Laymon CM,Sashin D,Carney JP,Ruszkiewicz J,Altenburger D,Becker CR,Lopresti BJ,Mason NS,Mountz JM,Price JC,Schavey R,Mathis CA

更新日期：2008-01-21 00:00:00

abstract：:We compare two different implementations of a 3D SPECT system model for iterative reconstruction, both of which compensate for non-uniform photon attenuation and depth-dependent system response. One implementation performs fast rotation of images represented using a basis of rectangular voxels, whereas the other repre...

journal_title：Physics in medicine and biology

authors： Yendiki A,Fessler JA

更新日期：2004-06-07 00:00:00

abstract：:This paper presents a new algorithm for constrained intensity-modulated radiotherapy (IMRT) planning, made tractable by a dimensionality reduction using a set of plans obtained by fast, unconstrained optimizations. The main result is to reduce planning time by an order of magnitude, producing viable five field prostat...

journal_title：Physics in medicine and biology

authors： Lu R,Radke RJ,Yang J,Happersett L,Yorke E,Jackson A

更新日期：2008-12-07 00:00:00

abstract：:An iterative Bayesian reconstruction algorithm for limited view angle tomography, or ectomography, based on the three-dimensional total variation (TV) norm has been developed. The TV norm has been described in the literature as a method for reducing noise in two-dimensional images while preserving edges, without intro...

journal_title：Physics in medicine and biology

authors： Persson M,Bone D,Elmqvist H

更新日期：2001-03-01 00:00:00

abstract：:To replace the conventional pinhole (normal cone-beam) collimator, a novel skew-slit collimator was previously proposed and a Novikov-type algorithm developed to reconstruct images using the skew-slit geometry. The goal of this paper is to develop a reconstruction algorithm that has better noise control than the Novik...

journal_title：Physics in medicine and biology

authors： Tang Q,Zeng GL,Huang Q

更新日期：2006-12-07 00:00:00

abstract：:This paper presents a computerized method for the selection of an irregular region of interest (ROI) in broadband ultrasound attenuation (BUA) images. A region growing algorithm searches an initial region in the posterior part of the calcaneus until the pixel with the lowest attenuation value is found; this is the sta...

journal_title：Physics in medicine and biology

authors： Damilakis J,Stratakis J,Perisinakis K,Gourtsoyiannis N

更新日期：2002-01-21 00:00:00

abstract：:For low-energy (up to 150 kV) x-rays, the ratio of mass-energy absorption coefficients for water to air, (mu(en)/rho)w.air, and the backscatter factor B are used in the conversion of air kerma, measured free-in-air, to water kerma on the surface of a water phantom. For clinical radiotherapy, similar conversion factors...

journal_title：Physics in medicine and biology

authors： Ma CM,Seuntjens JP

更新日期：1999-01-01 00:00:00

abstract：:To increase the scanning speed of cone-beam CT, a scanning configuration with three pairs of x-ray sources and panel detectors was proposed. In this paper, we apply the M-line-based backprojected filtration algorithm to this scanning configuration and propose a fast implementation for this algorithm. Compared with exi...

journal_title：Physics in medicine and biology

authors： Zhao Y,Zhu Y,Zhang P

更新日期：2010-12-07 00:00:00

abstract：:Heating induced near deep brain stimulation (DBS) lead electrodes during magnetic resonance imaging with a 3 T transceive head coil was measured, modeled, and imaged in three cadaveric porcine heads (mean body weight = 85.47 ± 3.19 kg, mean head weight = 5.78 ± 0.32 kg). The effect of the placement of the extra-crania...

journal_title：Physics in medicine and biology

authors： Shrivastava D,Abosch A,Hughes J,Goerke U,DelaBarre L,Visaria R,Harel N,Vaughan JT

更新日期：2012-09-07 00:00:00

abstract：:The aim of this study is to investigate the feasibility of using conventional jaws to deliver inverse planned intensity-modulated radiotherapy (IMRT) plans for patients with prostate cancer. For ten patients, each had one three-dimensional conformal plan (3D plan) and seven inverse IMRT plans using direct aperture opt...

journal_title：Physics in medicine and biology

authors： Kim Y,Verhey LJ,Xia P

更新日期：2007-04-21 00:00:00

abstract：:This work discusses the substitution of a gelatine physical gel matrix with a matrix made of poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (Pluronic F-127) in five 3D radiotherapy polymer gel dosimeters: MAGAT, PAGAT, NIPAM, VIPARnd (VIP) and VIPARCT (VIC). The current research outcomes s...

journal_title：Physics in medicine and biology

authors： Jaszczak M,Wach R,Maras P,Dudek M,Kozicki M

更新日期：2018-09-06 00:00:00

abstract：:A common dose-saving technique used in modern CT devices is automatic tube current modulation (TCM), which was originally designed to also reduce the dose in paediatric CT patients. In order to be able to deduce detailed organ doses of paediatric models, dose conversion coefficients normalized to CTDI(vol) for an eigh...

journal_title：Physics in medicine and biology

authors： Schlattl H,Zankl M,Becker J,Hoeschen C

更新日期：2012-10-21 00:00:00

abstract：:We have developed a model using Monte Carlo methods to simulate x-ray mammography. All possible physical processes of interaction of x-rays with matter have been taken into account. A simplified geometry of the mammographic apparatus has been considered along with a software phantom of compressed breast. The phantom m...

journal_title：Physics in medicine and biology

authors： Spyrou G,Tzanakos G,Bakas A,Panayiotakis G

更新日期：1998-11-01 00:00:00

abstract：:An x-ray fluorescence system with a synchrotron radiation source was used to quantify the levels of iron, copper and zinc in breast tissue specimens. Healthy tissue and breast carcinomas were investigated as an aid to understanding the mechanisms of breast cancer and as a possible complementary diagnostic tool. Eighty...

journal_title：Physics in medicine and biology

authors： Geraki K,Farquharson MJ,Bradley DA

更新日期：2002-07-07 00:00:00

abstract：:Monitoring the spatio-temporal characteristics of microcirculation is crucial for studying the functional activities of biotissue and the mechanism of disease. However, conventional methods used to measure blood flow suffer from limited spatial resolution or the injection of exogenous substances or the need of scannin...

journal_title：Physics in medicine and biology

authors： Cheng H,Luo Q,Liu Q,Lu Q,Gong H,Zeng S

更新日期：2004-04-07 00:00:00

abstract：:Diffusion tensor tractography (DTT) allows one to explore axonal connectivity patterns in neuronal tissue by linking local predominant diffusion directions determined by diffusion tensor imaging (DTI). The majority of existing tractography approaches use continuous coordinates for calculating single trajectories throu...

journal_title：Physics in medicine and biology

authors： Bodammer NC,Kaufmann J,Kanowski M,Tempelmann C

更新日期：2009-02-21 00:00:00

abstract：:The aim of this paper is to determine the dosimetric impact of trace elements in human tissues for low-energy photon sources used in brachytherapy. Monte Carlo dose calculations were used to investigate the dosimetric effect of trace elements present in normal or cancerous human tissues. The effect of individual trace...

journal_title：Physics in medicine and biology

authors： White SA,Landry G,van Gils F,Verhaegen F,Reniers B

更新日期：2012-06-07 00:00:00

abstract：:We present a new version of STIR (Software for Tomographic Image Reconstruction), an open source object-oriented library implemented in C++ for 3D positron emission tomography reconstruction. This library has been designed such that it can be used for many algorithms and scanner geometries, while being portable to var...

journal_title：Physics in medicine and biology

authors： Thielemans K,Tsoumpas C,Mustafovic S,Beisel T,Aguiar P,Dikaios N,Jacobson MW

更新日期：2012-02-21 00:00:00

abstract：:Tumour histological grade has prognostic implications in breast cancer. Tumour features in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and T2-weighted (T2W) imaging can provide related and complementary information in the analysis of breast lesions to improve MRI-based histological status prediction...

journal_title：Physics in medicine and biology

authors： Fan M,Liu Z,Xie S,Xu M,Wang S,Gao X,Li L

更新日期：2019-10-23 00:00:00

abstract：:Most existing spatiotemporal multi-dipole approaches for MEG/EEG source localization assume that the dipoles are active for the full time range being analysed. If the actual time range of activity of sources is significantly shorter than the time range being analysed, the detectability, localization and time-course de...

journal_title：Physics in medicine and biology

authors： Jun SC,George JS,Plis SM,Ranken DM,Schmidt DM,Wood CC

更新日期：2006-05-21 00:00:00

abstract：:This paper presents a compressed sensing (CS)-inspired reconstruction method for limited-angle computed tomography (CT). Currently, CS-inspired CT reconstructions are often performed by minimizing the total variation (TV) of a CT image subject to data consistency. A key to obtaining high image quality is to optimize t...

journal_title：Physics in medicine and biology

authors： Chen Z,Jin X,Li L,Wang G

更新日期：2013-04-07 00:00:00

abstract：:The University of Washington (UW) Clinical Neutron Therapy System (CNTS) has been used to treat over 3300 patients. Treatment planning for these patients is currently performed using an MV x-ray model in Pinnacle® adapted to fit measurements of fast neutron output factors, wedge factors, depth-dose and lateral profile...

journal_title：Physics in medicine and biology

authors： Moffitt GB,Wootton LS,Hårdemark B,Sandison GA,Laramore GE,Parvathaneni U,Stewart RD

更新日期：2020-08-31 00:00:00

abstract：:In recent years there has been a large amount of research into the potential use of radiation sensitive gels for three-dimensional verification of clinical radiotherapy doses. In this paper we report the use of a MAGIC gel dosimeter (Fong et al 2001 Phys. Med. Biol. 46 3105) for the verification of a specific patient'...

journal_title：Physics in medicine and biology

authors： Trapp JV,Partridge M,Hansen VN,Childs P,Bedford J,Warrington AP,Leach MO,Webb S

更新日期：2004-05-07 00:00:00

abstract：:Recently, a new family of low-cost x-radiation detectors have been developed, based on semiconducting polymer diodes, which are easy to process, mechanically flexible, relatively inexpensive, and able to cover large areas. To test their potential for radiotherapy applications such as beam monitors or dosimeters, as an...

journal_title：Physics in medicine and biology

authors： Mills CA,Chan YF,Intaniwet A,Shkunov M,Nisbet A,Keddie JL,Sellin PJ

更新日期：2013-07-07 00:00:00

abstract：:Histotripsy is a therapeutic ultrasound modality under development to liquefy tissue mechanically via bubble clouds. Image guidance of histotripsy requires both quantification of the bubble cloud activity and accurate delineation of the treatment zone. In this study, magnetic resonance (MR) and diagnostic ultrasound i...

journal_title：Physics in medicine and biology

authors： Anthony GJ,Bollen V,Hendley S,Antic T,Sammet S,Bader KB

更新日期：2019-05-02 00:00:00

abstract：:In this work, we propose a framework for optimizing spectral CT imaging parameters and hardware design with regard to material classification tasks. Compared with conventional CT, many more parameters must be considered when designing spectral CT systems and protocols. These choices will impact material classification...

journal_title：Physics in medicine and biology

authors： Rigie DS,La Rivière PJ

更新日期：2016-06-21 00:00:00