Paediatric entrance doses from exposure index in computed radiography.

abstract：:109Cd K x-ray fluorescence (XRF) measurement systems from two research centres were used to measure tibia lead content in a population (n = 530) of young adults. The group mean bone lead contents (+/-SEM) determined by McMaster University (n = 214) and the University of Maryland (n = 316) were 2.80 +/- 0.51 and 2.33 +...

journal_title：Physics in medicine and biology

authors： McNeill FE,Stokes L,Chettle DR,Kaye WE

更新日期：1999-09-01 00:00:00

abstract：:In a recent paper (Chamberland et al 2016 Phys. Med. Biol. 61 8214) develop a new Monte Carlo code called egs_brachy for brachytherapy treatments. It is based on EGSnrc, and written in the C++ programming language. In order to benchmark the egs_brachy code, the authors use it in various test case scenarios in which co...

journal_title：Physics in medicine and biology

authors： Yegin G

更新日期：2018-02-02 00:00:00

abstract：:Infrared measurements have been used to profile or image biological tissue, including human skin. Usually, analysis of such measurements has assumed that infrared absorption is due to water and collagen. Such an assumption may be reasonable for soft tissue, but introduction of exogenous agents into skin or the measure...

journal_title：Physics in medicine and biology

authors： Viator JA,Choi B,Peavy GM,Kimel S,Nelson JS

更新日期：2003-01-21 00:00:00

abstract：:A semi-empirical theory has been derived that relates the aluminum equivalence of various materials used in diagnostic radiology to their attenuation coefficients. The dependence of the aluminum hardness (AHE) and attenuation (AAE) equivalent on the beam quality is described in terms of effective energy. This 'aluminu...

journal_title：Physics in medicine and biology

authors： Nagel HD

更新日期：1986-12-01 00:00:00

abstract：:Deep learning models are highly parameterized, resulting in difficulty in inference and transfer learning for image recognition tasks. In this work, we propose a layered pathway evolution method to compress a deep convolutional neural network (DCNN) for classification of masses in digital breast tomosynthesis (DBT). T...

journal_title：Physics in medicine and biology

authors： Samala RK,Chan HP,Hadjiiski LM,Helvie MA,Richter C,Cha K

更新日期：2018-05-01 00:00:00

abstract：:Motion-adaptive radiotherapy aims to deliver a conformal dose to the target tumour with minimal normal tissue exposure by compensating for tumour motion in real time. The prediction as well as the gating of respiratory motion have received much attention over the last two decades for reducing the targeting error of th...

journal_title：Physics in medicine and biology

authors： Bukhari W,Hong SM

更新日期：2015-01-07 00:00:00

abstract：:The propagation of errors in quantitative biplane cineroentgenography was investigated to see which variables were the most critical. The analysis was carried out both for the propagation of root-mean-square errors and for errors as derived by a Taylor expansion of the reconstruction equations. The reconstruction is m...

journal_title：Physics in medicine and biology

authors： Smith WM,Starmer CF

更新日期：1978-07-01 00:00:00

abstract：:Recently, deep learning technology has achieved various successes in medical image analysis studies including computer-aided diagnosis (CADx). However, current CADx approaches based on deep learning have a limitation in interpreting diagnostic decisions. The limited interpretability is a major challenge for practical ...

journal_title：Physics in medicine and biology

authors： Kim ST,Lee JH,Lee H,Ro YM

更新日期：2018-12-04 00:00:00

abstract：:By the end of 2002, 33 398 patients worldwide had been treated with proton radiotherapy, 10 829 for eye diseases. The dose prediction algorithms used today for ocular proton therapy treatment planning rely on parameterizations of measured proton dose distributions, i.e., broad-beam and pencil-beam techniques, whose pr...

journal_title：Physics in medicine and biology

authors： Newhauser W,Koch N,Hummel S,Ziegler M,Titt U

更新日期：2005-11-21 00:00:00

abstract：:Quantification in cardiac mouse positron emission tomography (PET) imaging is limited by the imaging spatial resolution. Spillover of left ventricle (LV) myocardial activity into adjacent organs results in partial volume (PV) losses leading to underestimation of myocardial activity. A PV correction method was develope...

journal_title：Physics in medicine and biology

authors： Dumouchel T,Thorn S,Kordos M,DaSilva J,Beanlands RS,deKemp RA

更新日期：2012-07-07 00:00:00

abstract：:The optical properties (absorption and scattering coefficients and the scattering anisotropy factor) were measured in vitro for cartilage, liver, lung, muscle, myocardium, skin, and tumour (colon adenocarcinoma CC 531) at 630, 632.8, 790, 850 and 1064 nm. Rabbits, rats, piglets, goats, and dogs were used to obtain the...

journal_title：Physics in medicine and biology

authors： Beek JF,Blokland P,Posthumus P,Aalders M,Pickering JW,Sterenborg HJ,van Gemert MJ

更新日期：1997-11-01 00:00:00

abstract：:The most advanced delivery technique for proton radiotherapy is active spot scanning. So far, predominantly static targets have been treated with active spot scanning, since mobile targets in combination with dynamic treatment delivery can lead to interplay effects, causing inhomogeneous dose distributions. One way to...

journal_title：Physics in medicine and biology

authors： Knopf AC,Hong TS,Lomax A

更新日期：2011-11-21 00:00:00

abstract：:Random coincidences can contribute substantially to the background in positron emission tomography (PET). Several estimation methods are being used for correcting them. The goal of this study was to investigate the validity of techniques for random coincidence estimation, with various low-energy thresholds (LETs). Sim...

journal_title：Physics in medicine and biology

authors： Torres-Espallardo I,Rafecas M,Spanoudaki V,McElroy DP,Ziegler SI

更新日期：2008-05-07 00:00:00

abstract：:A new component module (CM), designated DYNVMLC, was developed to fully model the geometry of the Varian Millennium 120 leaf collimator using the BEAMnrc Monte Carlo code. The model includes details such as the leaf driving screw hole, support railing groove and leaf tips. Further modifications also allow sampling of ...

journal_title：Physics in medicine and biology

authors： Heath E,Seuntjens J

更新日期：2003-12-21 00:00:00

abstract：:In order to optimize external-beam conformal radiotherapy, patient movement during treatment must be minimized. For treatment on the upper torso, the target organs are known to move substantially due to patient respiration. This paper deals with the technical aspects of gating the radiotherapy beam synchronously with ...

journal_title：Physics in medicine and biology

authors： Kubo HD,Hill BC

更新日期：1996-01-01 00:00:00

abstract：:The formulation of intensity modulated radiation therapy (IMRT) planning aspects frequently uses the dose-volume histogram (DVH), whereas plan computations often happen in the more desirable convex IMRT optimization framework. Inspired by a recent publication of Zinchenko et al (2008 Phys. Med. Biol. 53 3231-50), this...

journal_title：Physics in medicine and biology

authors： Kratt K,Scherrer A

更新日期：2009-06-21 00:00:00

abstract：:Magnetic Resonance Electrical Impedance Tomography (MREIT) is an MRI method that enables mapping of internal conductivity and/or current density via measurements of magnetic flux density signals. The MREIT measures only the z-component of the induced magnetic flux density B = (Bx, By, Bz) by external current injection...

journal_title：Physics in medicine and biology

authors： Jeong WC,Chauhan M,Sajib SZ,Kim HJ,Serša I,Kwon OI,Woo EJ

更新日期：2014-09-07 00:00:00

abstract：:The purpose of this study was the characterization of local magnetic susceptibility deviations by spectral analysis of their induced magnetic field inhomogeneities. Magnetic resonance spectra and related signal decay curves of local susceptibility deviations were simulated for different volume fractions and compositio...

journal_title：Physics in medicine and biology

authors： Seppenwoolde JH,van Zijtveld M,Bakker CJ

更新日期：2005-01-21 00:00:00

abstract：:Scattered radiation from within the treatment head can contribute significant dose to all parts of a radiotherapy treatment field. A multileaf collimator may be used to create an arbitrarily shaped field, and may also be used, under dynamic control, to modulate the beam intensity over the field. This method of intensi...

journal_title：Physics in medicine and biology

authors： Hounsell AR,Wilkinson JM

更新日期：1997-09-01 00:00:00

abstract：:We investigate the effect of multiple scattering on the optical coherence tomography (OCT) signal and the Doppler OCT signal of flowing blood. Doppler OCT measurements at 1300 nm are performed on flowing diluted porcine blood with hematocrit ranging between 0% and 15%. Measured blood hematocrit and mean red blood cell...

journal_title：Physics in medicine and biology

authors： Kalkman J,Bykov AV,Streekstra GJ,van Leeuwen TG

更新日期：2012-04-07 00:00:00

abstract：:A technique is described by which the regional distribution of bone mineral can be determined in bone samples from small animals. The technique employs an Anger camera interfaced to a medical computer. High resolution (less than 1 mm) imaging is possible by producing magnified images of the bone samples. Regional dens...

journal_title：Physics in medicine and biology

authors： LeBlanc A,Evans H,Jhingran S,Johnson P

更新日期：1984-01-01 00:00:00

abstract：:A method of measuring the image quality of medical imaging equipment is considered within the framework of statistical decision theory. In this approach, images are regarded as random vectors and image quality is defined in the context of the image information available for performing a specified detection or discrimi...

journal_title：Physics in medicine and biology

authors： Tapiovaara MJ,Wagner RF

更新日期：1993-01-01 00:00:00

abstract：:Curves relating beam energy, scattering foil thickness, central-axis depth-dose, and beam flatness have been generated using data taken on a Siemens 200A betatron. The curve set allows a single combination of tungsten foil thickness and electron beam energy to be chosen that will provide the optimum depth-dose distrib...

journal_title：Physics in medicine and biology

authors： Marbach JR,Almond PR

更新日期：1981-05-01 00:00:00

abstract：:In recent years, optical techniques based on diffusion approximation have demonstrated their ability to gain rich spectral information about bone. However, these methods normally assume homogeneity, while cancellous bone and marrow form a highly heterogeneous two-phase medium. This paper studies the limitations of thi...

journal_title：Physics in medicine and biology

authors： Margallo-Balbás E,Taroni P,Pifferi A,Koolstra JH,v Ruijven LJ,French PJ

更新日期：2010-09-07 00:00:00

abstract：:Radiotherapy treatment planning relies on the use of geometrically correct images. This paper presents a fully automatic tool for correcting MR images for the effects of B(0) inhomogeneities. The post-processing method is based on the gradient-reversal technique of Chang and Fitzpatrick (1992 IEEE Trans. Med. Imaging ...

journal_title：Physics in medicine and biology

authors： Reinsberg SA,Doran SJ,Charles-Edwards EM,Leach MO

更新日期：2005-06-07 00:00:00

abstract：:Cardiac and respiratory motion artefacts in PET imaging have been traditionally resolved by acquiring the data in gated mode. However, gated PET images are usually characterized by high noise content due to their low photon statistics. In this paper, we present a novel 4D model for the PET imaging system, which can in...

journal_title：Physics in medicine and biology

authors： Qiao F,Pan T,Clark JW Jr,Mawlawi OR

更新日期：2006-08-07 00:00:00

abstract：:To generate large thermal lesions in ultrasound thermal therapy, cooling intermissions are usually introduced during the treatment to prevent near-field heating, which leads to a long treatment time. A possible strategy to shorten the total treatment time is to eliminate the cooling intermissions. In this study, the t...

journal_title：Physics in medicine and biology

authors： Liu HL,Chen YY,Yen JY,Lin WL

更新日期：2003-05-07 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：: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：:We propose a hybrid multiobjective (MO) evolutionary optimization algorithm (MOEA) for intensity-modulated radiotherapy inverse planning and apply it to optimize the number of incident beams, their orientations and intensity profiles. The algorithm produces a set of efficient solutions, which represent different clini...

journal_title：Physics in medicine and biology

authors： Schreibmann E,Lahanas M,Xing L,Baltas D

更新日期：2004-03-07 00:00:00