Physics of contrast mechanism and averaging effect of linear attenuation coefficients in a computerized transverse axial tomography CTAT) transmission scanner.

abstract：:Single energy x-ray analysis is explored in the context of computed tomography (CT), whereby Hounsfield numbers (HN) are used to estimate electron density N(e) and parameters that describe composition. We examine measurements with tissue substitute materials and theoretical HN for a broad range of tissues. Results are...

journal_title：Physics in medicine and biology

authors： Midgley SM

更新日期：2012-12-07 00:00:00

abstract：:Diffraction-enhanced imaging (DEI) is an analyser-based x-ray imaging method that produces separate images depicting the projected x-ray absorption and refractive properties of an object. Because the imaging model of DEI does not account for ultra-small-angle x-ray scattering (USAXS), the images produced in DEI can co...

journal_title：Physics in medicine and biology

authors： Chou CY,Anastasio MA,Brankov JG,Wernick MN,Brey EM,Connor DM,Zhong Z

更新日期：2007-04-07 00:00:00

abstract：:This paper presents calculated specific absorption rate (SAR) dosimetry in 4 and 8 week Japanese pregnant-woman models exposed to plane waves over the frequency range of 10 MHz-1.5 GHz. Two types of 2 mm spatial-resolution pregnant-woman models comprised a woman model, which is similar to the average-sized Japanese ad...

journal_title：Physics in medicine and biology

authors： Kawai H,Nagaoka T,Watanabe S,Saito K,Takahashi M,Ito K

更新日期：2010-01-07 00:00:00

abstract：:Two different classifiers, an artificial neural network (ANN) and a hybrid system (one step rule-based method followed by an artificial neural network) have been investigated to merge computer-extracted features in the task of differentiating between malignant and benign masses. A database consisting of 65 cases (38 m...

journal_title：Physics in medicine and biology

authors： Huo Z,Giger ML,Metz CE

更新日期：1999-10-01 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：:This paper evaluates results of a survey of electrostimulation models of myelinated nerve. Participants were asked to determine thresholds of excitation for 18 cases involving different characteristics of the neuron, the stimulation waveform, and the electrode arrangement. Responses were received from 7 investigators ...

journal_title：Physics in medicine and biology

authors： Reilly JP

更新日期：2016-06-21 00:00:00

abstract：:The reference levels and maximum permissible exposure values for magnetic fields that are currently used have been derived from basic restrictions under the assumption of upright standing body models in a standard posture, i.e. with arms laterally down and without contact with metallic objects. Moreover, if anatomical...

journal_title：Physics in medicine and biology

authors： Schmid G,Hirtl R

更新日期：2016-06-21 00:00:00

abstract：:The widely applied single-interaction analytic expression characterizing the energy resolution component of the angular resolution precision for an electronically collimated point source is extended to include multiple-interaction Compton scatter sequences as well as sequences terminated by photoelectric absorption. T...

journal_title：Physics in medicine and biology

authors： Durkee JW Jr,Antich PP,Tsyganov EN,Constantinescu A,Kulkarni PV,Smith BJ,Arbique GM,Lewis MA,Nguyen T,Raheja A,Thambi G,Parkey RW

更新日期：1998-10-01 00:00:00

abstract：:Diffuse optical imaging using non-ionizing radiation is a non-invasive method that shows promise towards breast cancer diagnosis. Hand-held optical imagers show potential for clinical translation of the technology, yet they have not been used towards 3D tomography. Herein, 3D tomography of human breast tissue in vivo ...

journal_title：Physics in medicine and biology

authors： Erickson SJ,Martinez SL,DeCerce J,Romero A,Caldera L,Godavarty A

更新日期：2013-03-07 00:00:00

abstract：:Magnetic resonance imaging (MRI) may be used to image three-dimensional dose distributions of ionizing radiation in tissue equivalent gels infused with ferrous sulphate solutions, commonly known as Fricke gels. In this technique, ferrous (Fe2+) ions are oxidized to ferric (Fe3+) ions by free radicals produced by ioniz...

journal_title：Physics in medicine and biology

authors： Harris PJ,Piercy A,Baldock C

更新日期：1996-09-01 00:00:00

abstract：:Several studies have been appeared, up to now, that indicate the effect of accurate simulation on dose received by different substructures of the eye, irradiated by external beams of short-range radiation such as electron. Different representations of the eye have consequently been introduced. Their accuracies depend ...

journal_title：Physics in medicine and biology

authors： Vejdani-Noghreiyan A,Ebrahimi-Khankook A

更新日期：2019-07-02 00:00:00

abstract：:Assessment of radiation absorbed dose to internal organs of the body from the intake of radionuclides or, in the medical setting through the injection of radiopharmaceuticals, is generally performed based upon reference biokinetic models or patient imaging data, respectively. Biokinetic models estimate the time course...

journal_title：Physics in medicine and biology

authors： Schwarz BC,Godwin WJ,Wayson MB,Dewji SA,Jokisch DW,Lee C,Bolch WE

更新日期：2020-11-03 00:00:00

abstract：:We introduce a novel x-ray imaging approach that yields information about the local texture of structures smaller than the image pixel resolution inside an object. The approach is based on a recently developed x-ray dark-field imaging technique, using scattering from sub-micron structures in the sample. We show that t...

journal_title：Physics in medicine and biology

authors： Jensen TH,Bech M,Bunk O,Donath T,David C,Feidenhans'l R,Pfeiffer F

更新日期：2010-06-21 00:00:00

abstract：:Near-infrared fluorescence optical imaging has the unique opportunity of differentiating diseased lesions from normal lesions based upon environmentally indicated changes in the lifetime of a fluorescent imaging agent. In this paper, we demonstrate three-dimensional lifetime tomography using the gradient-based penalty...

journal_title：Physics in medicine and biology

authors： Roy R,Godavarty A,Sevick-Muraca EM

更新日期：2007-07-21 00:00:00

abstract：:The aim of magnetic resonance electrical impedance tomography (MREIT) is to visualize the electrical properties, conductivity or current density of an object by injection of current. Recently, the prolonged data acquisition time when using the injected current nonlinear encoding (ICNE) method has been advantageous for...

journal_title：Physics in medicine and biology

authors： Nam HS,Kwon OI

更新日期：2010-05-07 00:00:00

abstract：:Does the posture of a patient have an effect on the organ and tissue absorbed doses caused by x-ray examinations? This study aims to find the answer to this question, based on Monte Carlo (MC) simulations of commonly performed x-ray examinations using adult phantoms modelled to represent humans in standing as well as ...

journal_title：Physics in medicine and biology

authors： Cassola VF,Kramer R,Brayner C,Khoury HJ

更新日期：2010-08-07 00:00:00

abstract：:There is a need to verify the accuracy of general purpose Monte Carlo codes like EGSnrc, which are commonly employed for investigations of dosimetric problems in radiation therapy. A number of experimental benchmarks have been published to compare calculated values of absorbed dose to experimentally determined values....

journal_title：Physics in medicine and biology

authors： Renner F,Wulff J,Kapsch RP,Zink K

更新日期：2015-10-07 00:00:00

abstract：:As an x-ray beam goes through the human body, it will collect important information via interaction with tissues. Since this interaction is energy-sensitive, the state-of-the-art spectral CT technologies provide higher quality images of biological tissues with x-ray energy information (or spectral information). With e...

journal_title：Physics in medicine and biology

authors： Shi Z,Yang H,Cong W,Wang G

更新日期：2016-06-07 00:00:00

abstract：:To evaluate the effect of approximations in clinical analytical calculations performed by a treatment planning system (TPS) on dosimetric indices in intensity modulated proton therapy. TPS calculated dose distributions were compared with dose distributions as estimated by Monte Carlo (MC) simulations, calculated with ...

journal_title：Physics in medicine and biology

authors： Yepes P,Adair A,Grosshans D,Mirkovic D,Poenisch F,Titt U,Wang Q,Mohan R

更新日期：2018-02-09 00:00:00

abstract：:Magnetic resonance imaging is effective for non-invasive detection of myocardial diseases by extracellular volume fraction (ECV) estimation. A new methodology for T1 and ECV mapping is tested in this work, comparing results with other well-consolidated methods. The associated level of uncertainty for data was also est...

journal_title：Physics in medicine and biology

authors： Borrazzo C,Pacilio M,Galea N,Preziosi E,Carnì M,Francone M,Catalano C,Carbone I

更新日期：2019-02-11 00:00:00

abstract：:Brain stereotactic radiosurgery (SRS) treatments require multiple quality assurance (QA) procedures to ensure accurate and precise treatment delivery. As single-isocenter multitarget SRS treatments become more popular, the quantification of off-axis accuracy of the linear accelerator is crucial. In this study, a novel...

journal_title：Physics in medicine and biology

authors： Capaldi DPI,Skinner LB,Dubrowski P,Yu AS

更新日期：2020-06-10 00:00:00

abstract：:Ultraviolet (UV) treatment dose is determined by the length of time that a patient spends in a phototherapy cabin. The output from UV fluorescent lamps declines with use and a method is needed to compensate for the change in irradiance and to identify and replace any lamps that fail. The decline in lamp output with ag...

journal_title：Physics in medicine and biology

authors： Amatiello H,Martin CJ

更新日期：2006-01-21 00:00:00

abstract：:3D acquisition and reconstruction in positron emission tomography (PET) produce data with improved signal-to-noise ratios compared with conventional 2D slice-oriented methods. However, the sensitivity increase is accompanied by an increase in the number of scattered photons and random coincidences detected. This paper...

journal_title：Physics in medicine and biology

authors： Bailey DL,Meikle SR

更新日期：1994-03-01 00:00:00

abstract：:We have developed deformable and durable optical tissue phantoms with a simple and well-defined microstructure including a novel combination of scatterers and a matrix material. These were developed for speckle and elastography investigations in optical coherence tomography, but should prove useful in many other field...

journal_title：Physics in medicine and biology

authors： Bisaillon CE,Lamouche G,Maciejko R,Dufour M,Monchalin JP

更新日期：2008-07-07 00:00:00

abstract：:The purpose of this work is to develop and test a method to estimate the relative and absolute absorbed radiation dose from axial and spiral CT scans using a Monte Carlo approach. Initial testing was done in phantoms and preliminary results were obtained from a standard mathematical anthropomorphic model (MIRD V) and ...

journal_title：Physics in medicine and biology

authors： Jarry G,DeMarco JJ,Beifuss U,Cagnon CH,McNitt-Gray MF

更新日期：2003-08-21 00:00:00

abstract：:The implementation of two algorithms for calculating dose distributions for radiation therapy treatment planning of intermediate energy proton beams is described. A pencil kernel algorithm and a depth penetration algorithm have been incorporated into a commercial three dimensional treatment planning system (Helax-TMS,...

journal_title：Physics in medicine and biology

authors： Russell KR,Isacsson U,Saxner M,Ahnesjö A,Montelius A,Grusell E,Dahlgren CV,Lorin S,Glimelius B

更新日期：2000-01-01 00:00:00

abstract：:The purpose of this study was to apply a novel method of multiscale echo texture analysis for distinguishing benign (hemangiomas) from malignant (hepatocellular carcinomas (HCCs) and metastases) focal liver lesions in B-mode ultrasound images. In this method, regions of interest (ROIs) extracted from within the lesion...

journal_title：Physics in medicine and biology

authors： Yoshida H,Casalino DD,Keserci B,Coskun A,Ozturk O,Savranlar A

更新日期：2003-11-21 00:00:00

abstract：:EEG recordings made in combined EEG-fMRI studies are corrupted by gradient artefacts (GAs) resulting from the interaction of the EEG system with the time-varying magnetic field gradients used in MRI. The dominant contribution to the GA arises from interaction with the leads of the EEG cap and the human head, but artef...

journal_title：Physics in medicine and biology

authors： Chowdhury ME,Mullinger KJ,Bowtell R

更新日期：2015-06-21 00:00:00

abstract：:Sparse-view CT reconstruction algorithms via total variation (TV) optimize the data iteratively on the basis of a noise- and artifact-reducing model, resulting in significant radiation dose reduction while maintaining image quality. However, the piecewise constant assumption of TV minimization often leads to the appea...

journal_title：Physics in medicine and biology

authors： Niu S,Gao Y,Bian Z,Huang J,Chen W,Yu G,Liang Z,Ma J

更新日期：2014-06-21 00:00:00

abstract：:Optically stimulated luminescent dosimeters (OSLDs) are becoming increasingly popular for measuring an absorbed dose in clinical radiotherapy. OSLDs have known energy dependence, and this is accounted for by either calibrating the OSLD with a specific nominal energy, or using a standard energy correction factor to acc...

journal_title：Physics in medicine and biology

authors： Scarboro SB,Followill DS,Kerns JR,White RA,Kry SF

更新日期：2012-05-07 00:00:00