A Monte Carlo study of the variation of electron fluence in water from a 6 MV photon beam outside of the field.

abstract：:Analytic solutions to the time-dependent multiregion bioheat equation are evaluated numerically for cartesian and spherical models. Principle and alternate branch contributions to the solutions are examined. The calculations include a parametric investigation and analyses of temperature behaviour in idealised upper th...

journal_title：Physics in medicine and biology

authors： Durkee JW Jr,Antich PP,Lee CE

更新日期：1990-07-01 00:00:00

abstract：:The total ionisation produced by ions stopped in nitrogen, methane and carbon dioxide has been measured in the energy range 25-375 keV using a chamber described previously. The chamber was operated alternately as a proportional counter and as an ionisation chamber to measure respectively the particle rate and the tota...

journal_title：Physics in medicine and biology

authors： Nguyen VD,Chemtob M,Chary J,Posny F,Parmentier N

更新日期：1980-05-01 00:00:00

abstract：:Uncemented prosthetic joint implants used in orthopaedic surgery are usually coated with a porous surface to encourage bone ingrowth. Better contact between the endosteal bone and the porous surface improves ingrowth, and such contact may be increased if the joint further subsides into position in the first weeks foll...

journal_title：Physics in medicine and biology

authors： Berry E,Langkamer VG,Jackson PC,Snow M,Goddard PR,Wells PN

更新日期：1993-02-01 00:00:00

abstract：:Large volume tissue-equivalent proportional counters are of interest in radiation protection metrology, as the sensitivity in terms of counts per unit absorbed dose in these devices increases as the square of the counter diameter. Conventional solutions to the problem of maintaining a uniform electric field within a c...

journal_title：Physics in medicine and biology

authors： Verma PK,Waker AJ

更新日期：1992-10-01 00:00:00

abstract：:Induction cookers are a type of cooking appliance that uses an intermediate-frequency magnetic field to heat the cooking vessel. The magnetic flux density produced by an induction cooker during operation was measured according to the EN 62233 standard, and the measured values were below the limits set in the standard....

journal_title：Physics in medicine and biology

authors： Kos B,Valič B,Miklavčič D,Kotnik T,Gajšek P

更新日期：2011-10-07 00:00:00

abstract：:Source anisotropy is a very important factor in the brachytherapy quality assurance of high-dose rate (HDR) 192Ir afterloading stepping sources. If anisotropy is not taken into account then doses received by a brachytherapy patient in certain directions can be in error by a clinically significant amount. Experimental ...

journal_title：Physics in medicine and biology

authors： Baltas D,Giannouli S,Garbi A,Diakonos F,Geramani K,Ioannidis GT,Tsalpatouros A,Uzunoglu N,Kolotas C,Zamboglou N

更新日期：1998-06-01 00:00:00

abstract：:The purpose of this work was to validate GATE-based clinical scale absorbed dose calculations in nuclear medicine dosimetry. GATE (version 6.2) and MCNPX (version 2.7.a) were used to derive dosimetric parameters (absorbed fractions, specific absorbed fractions and S-values) for the reference female computational model...

journal_title：Physics in medicine and biology

authors： Villoing D,Marcatili S,Garcia MP,Bardiès M

更新日期：2017-03-07 00:00:00

abstract：:In charged particle therapy with pencil beam scanning (PBS), localization of the dose in the Bragg peak makes dose distributions sensitive to lateral tissue heterogeneities. The sensitivity of a PBS plan to lateral tissue heterogeneities can be reduced by selecting appropriate beam angles. The purpose of this study is...

journal_title：Physics in medicine and biology

authors： Toramatsu C,Inaniwa T

更新日期：2016-12-21 00:00:00

abstract：:Radiochromic films are useful as dosimeters in high-precision radiotherapy owing to their high spatial resolution. However, when a particle beam is measured using a radiochromic film, the dose cannot be estimated accurately because the film darkness varies with variations in linear energy transfer (LET). This paper pr...

journal_title：Physics in medicine and biology

authors： Kawashima M,Matsumura A,Souda H,Tashiro M

更新日期：2020-06-15 00:00:00

abstract：:Ion beam therapy offers the possibility of a highly conformal tumor-dose distribution; however, this technique is extremely sensitive to inaccuracies in the treatment procedures. Ambiguities in the conversion of Hounsfield units of the treatment planning x-ray CT to relative stopping power (RSP) can cause uncertaintie...

journal_title：Physics in medicine and biology

authors： Meyer S,Gianoli C,Magallanes L,Kopp B,Tessonnier T,Landry G,Dedes G,Voss B,Parodi K

更新日期：2017-02-07 00:00:00

abstract：:In this paper we present a generalized Deep Learning-based approach for solving ill-posed large-scale inverse problems occuring in medical image reconstruction. Recently, Deep Learning methods using iterative neural networks (NNs) and cascaded NNs have been reported to achieve state-of-the-art results with respect to ...

journal_title：Physics in medicine and biology

authors： Kofler A,Haltmeier M,Schaeffter T,Kachelrieß M,Dewey M,Wald C,Kolbitsch C

更新日期：2020-07-06 00:00:00

abstract：:The exponential edge-gradient effect must arise in any x-ray transmission CT scanner whenever long sharp edges of high contrast are encountered. The effect is non-linear and is due to the interaction of the exponential law of x-ray attenuation and the finite width of the scanning beam in the x-y plane. The error induc...

journal_title：Physics in medicine and biology

authors： Joseph PM,Spital RD

更新日期：1981-05-01 00:00:00

abstract：:In previous work we demonstrated the potential of positron emission tomography (PET) detectors with depth-of-interaction (DOI) encoding capability based on phosphor-coated crystals. A DOI resolution of 8 mm full-width at half-maximum was obtained for 20 mm long scintillator crystals using a delayed charge integration ...

journal_title：Physics in medicine and biology

authors： Roncali E,Phipps JE,Marcu L,Cherry SR

更新日期：2012-10-21 00:00:00

abstract：:Gel dosimetry based on magnetic resonance imaging (MRI) has previously been shown to provide verification of calculated dose distributions in soft tissue equivalent homogeneous phantoms. This study demonstrates how measurements of dose distribution can also be achieved in a phantom containing porous, lung-equivalent, ...

journal_title：Physics in medicine and biology

authors： Olberg S,Skretting A,Bruland O,Olsen DR

更新日期：2000-10-01 00:00:00

abstract：:While megavoltage cone-beam computed tomography (CBCT) using an electronic portal imaging device (EPID) provides many advantages over kilovoltage (kV) CBCT, clinical adoption is limited by its high doses. Multi-layer imager (MLI) EPIDs increase DQE(0) while maintaining high resolution. However, even well-designed, hig...

journal_title：Physics in medicine and biology

authors： Hu YH,Rottmann J,Fueglistaller R,Myronakis M,Wang A,Huber P,Shedlock D,Morf D,Baturin P,Star-Lack J,Berbeco R

更新日期：2018-01-30 00:00:00

abstract：:This study investigated the temperature elevation in the eye of anatomically based human head models for plane-wave exposures. The finite-difference time-domain method is used for analyzing electromagnetic absorption and temperature elevation. The eyes in the anatomic models have average dimensions and weight. Computa...

journal_title：Physics in medicine and biology

authors： Hirata A,Watanabe S,Fujiwara O,Kojima M,Sasaki K,Shiozawa T

更新日期：2007-11-07 00:00:00

abstract：:The (83)Kr magnetic resonance (MR) relaxation time T(1) of krypton gas in contact with model surfaces was previously found to be highly sensitive to surface composition, surface-to-volume ratio, and surface temperature. The work presented here explored aspects of pulmonary (83)Kr T(1) relaxation measurements in excise...

journal_title：Physics in medicine and biology

authors： Stupic KF,Elkins ND,Pavlovskaya GE,Repine JE,Meersmann T

更新日期：2011-07-07 00:00:00

abstract：:Usually, Monte Carlo models are validated against experimental data. However, models of multiple Coulomb scattering (MCS) in the Gaussian approximation are exceptional in that we have theories which are probably more accurate than the experiments which have, so far, been done to test them. In problems directly sensiti...

journal_title：Physics in medicine and biology

authors： Makarova A,Gottschalk B,Sauerwein W

更新日期：2017-07-06 00:00:00

abstract：:The device developed by the authors and described here enables the user to measure the depth from the water surface to the point of measurement for a cylindrical ion chamber with a waterproof plastic cap in a water phantom, free of surface-tension error with a high precision. The device seeks vertical orientation and ...

journal_title：Physics in medicine and biology

authors： Tailor RC,Tello VM

更新日期：1995-08-01 00:00:00

abstract：:A stable cryogel dosimeter was prepared using ferrous benzoic xylenol orange (FBX) in a transparent poly-(vinyl alcohol) (PVA) cryogel matrix. Dose response was evaluated for different numbers of freeze-thaw cycles (FTCs), different concentrations of PVA, and ratios of water/dimethyl sulfoxide. Linear relationships be...

journal_title：Physics in medicine and biology

authors： Eyadeh MM,Farrell TJ,Diamond KR

更新日期：2014-04-07 00:00:00

abstract：:In medical imaging different techniques have been developed to gain information from inside a tissue. Optoacoustics is a method to generate tomography pictures of tissue using Q-switched laser pulses. Due to thermal and pressure confinement, a short light pulse generates a pressure distribution inside tissue, which mi...

journal_title：Physics in medicine and biology

authors： Köstli KP,Frenz M,Bebie H,Weber HP

更新日期：2001-07-01 00:00:00

abstract：:Intensity modulated proton radiotherapy (IMPT) can reduce the dose to critical structures by optimizing the distribution and intensity of individual pencil beams. The IMPT can be delivered by dynamically scanning a pencil beam with variable intensity and energy across the tumor target volume. The lateral penumbra of a...

journal_title：Physics in medicine and biology

authors： Safai S,Bortfeld T,Engelsman M

更新日期：2008-03-21 00:00:00

abstract：:In brachytherapy, plans are routinely calculated using the AAPM TG43 formalism which considers the patient as a simple water object. An accurate modeling of the physical processes considering patient heterogeneity using Monte Carlo simulation (MCS) methods is currently too time-consuming and computationally demanding ...

journal_title：Physics in medicine and biology

authors： Lemaréchal Y,Bert J,Falconnet C,Després P,Valeri A,Schick U,Pradier O,Garcia MP,Boussion N,Visvikis D

更新日期：2015-07-07 00:00:00

abstract：:Projection and backprojection are operations that arise frequently in tomographic imaging. Recently, we proposed a new method for projection and backprojection, which we call distance-driven, and that offers low arithmetic cost and a highly sequential memory access pattern. Furthermore, distance-driven projection and ...

journal_title：Physics in medicine and biology

authors： De Man B,Basu S

更新日期：2004-06-07 00:00:00

abstract：:Positron emission tomography (PET) has been suggested as an imaging technique for in vivo proton dose and range verification after proton induced-tissue activation. During proton treatment, irradiated tissue is activated and decays while emitting positrons. In this paper, we assessed the feasibility of using PET imagi...

journal_title：Physics in medicine and biology

authors： Cho J,Ibbott G,Gillin M,Gonzalez-Lepera C,Min CH,Zhu X,El Fakhri G,Paganetti H,Mawlawi O

更新日期：2013-06-07 00:00:00

abstract：:Stroke lesion volume is a key radiologic measurement in assessing prognosis of acute ischemic stroke (AIS) patients. The aim of this paper is to develop an automated segmentation method for accurately segmenting follow-up ischemic and hemorrhagic lesion from multislice non-contrast CT (NCCT) volumes of AIS patients. T...

journal_title：Physics in medicine and biology

authors： Kuang H,Menon BK,Qiu W

更新日期：2020-11-05 00:00:00

abstract：:This paper describes a neural network (NN) regression model for relative dose computation. The input signal of the NN model includes depths and field sizes and the output is the relative dose, for example, percentage depth dose (%DD) or tissue-air ratio (TAR) in this paper. After a functional link has been created, th...

journal_title：Physics in medicine and biology

authors： Wu X,Zhu Y

更新日期：2000-04-01 00:00:00

abstract：:This study presents the computational dosimetry of contact currents for grounded and ungrounded human models. The uncertainty of the quasi-static (QS) approximation of the in situ electric field induced in a grounded/ungrounded human body due to the contact current is first estimated. Different scenarios of cylindrica...

journal_title：Physics in medicine and biology

authors： Chan KH,Hattori J,Laakso I,Hirata A,Taki M

更新日期：2013-08-07 00:00:00

abstract：:We propose a retrospective respiratory gating algorithm to generate dynamic CT studies. To this end, we compared three different methods of extracting the respiratory signal from the projections of small-animal cone-beam computed tomography (CBCT) scanners. Given a set of frames acquired from a certain axial angle, su...

journal_title：Physics in medicine and biology

authors： Chavarrías C,Vaquero JJ,Sisniega A,Rodríguez-Ruano A,Soto-Montenegro ML,García-Barreno P,Desco M

更新日期：2008-09-07 00:00:00

abstract：:Optical topography is a method for visualization of conical activity. Ways of improving the spatial resolution of the topographical image with three arrangements of optical fibres are discussed. A distribution of sensitivity is obtained from the phantom experiment, and used to reconstruct topographical images of an ac...

journal_title：Physics in medicine and biology

authors： Yamamoto T,Maki A,Kadoya T,Tanikawa Y,Yamad Y,Okada E,Koizumi H

更新日期：2002-09-21 00:00:00