Biological dosimetry of complex ion radiation fields.

abstract：:New organ dose conversion coefficients for coronary angiographic interventions are presented, as well as dose distributions and resulting maximal local dose conversion coefficients in the relevant organs. For the Monte Carlo based simulations, voxel models of the human anatomy were employed which represent the average...

journal_title：Physics in medicine and biology

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

更新日期：2007-08-07 00:00:00

abstract：:The combined build-up and attenuation factor, B exp (-mu r), of point isotropic photon sources in a water medium has been calculated using the Monte Carlo method, for energies (20-1500 keV) and distances (1-10 cm) relevant in brachytherapy. For the transport of photons and electrons, up-to-date and self-consistent tot...

journal_title：Physics in medicine and biology

authors： Angelopoulos A,Perris A,Sakellariou K,Sakelliou L,Sarigiannis K,Zarris G

更新日期：1991-06-01 00:00:00

abstract：:We propose a regularized least-squares method for reconstructing 2D velocity vector fields within the left ventricular cavity from single-view color Doppler echocardiographic images. Vector flow mapping is formulated as a quadratic optimization problem based on an [Formula: see text]-norm minimization of a cost functi...

journal_title：Physics in medicine and biology

authors： Assi KC,Gay E,Chnafa C,Mendez S,Nicoud F,Abascal JFPJ,Lantelme P,Tournoux F,Garcia D

更新日期：2017-08-11 00:00:00

abstract：:This paper addresses fundamental issues that underlie the interpretation of images acquired from turbid tissues by optical-coherence tomography (OCT). The attenuation and backscattering properties of freshly excised rat arteries and their dependence on the focusing and collection optics of the OCT system were measured...

journal_title：Physics in medicine and biology

authors： Schmitt JM,Knüttel A,Yadlowsky M,Eckhaus MA

更新日期：1994-10-01 00:00:00

abstract：:A Monte Carlo computer program has been developed for the computation of integral radiation dose to the breast in xeromammography. The results are given in terms of the integral dose per unit area of the breast per unit incident exposure. The calculations have been made for monoenergetic incident photons and the resul...

journal_title：Physics in medicine and biology

authors： Dance DR

更新日期：1980-01-01 00:00:00

abstract：:It was observed that the radiation output of x-ray tubes falls off exponentially during an exposure with a time constant of about 120 ms. The equilibrium value is approximately 15% lower than that at the beginning of the exposure. The clinically noticeable consequences are discrepancies in x-ray generator calibration,...

journal_title：Physics in medicine and biology

authors： Brezovich IA,Barnes GT

更新日期：1980-03-01 00:00:00

abstract：:Energy and angular distributions of electron beams with different energies were simulated by Monte Carlo calculations. These beams were generated by the NOVAC7 system (Hitesys, Italy), a mobile electron accelerator specifically dedicated to intra-operative radiation therapy (IORT). The electron beam simulations were v...

journal_title：Physics in medicine and biology

authors： Pimpinella M,Mihailescu D,Guerra AS,Laitano RF

更新日期：2007-10-21 00:00:00

abstract：:There are three ways to determine the spectrum of a clinical photon beam: direct measurement, modelling the source and reconstruction from ion-chamber measurements. We focus on reconstruction because the necessary equipment is readily available and it provides independent confirmation of source models for a given mach...

journal_title：Physics in medicine and biology

authors： Armbruster B,Hamilton RJ,Kuehl AK

更新日期：2004-11-21 00:00:00

abstract：:In this study, the safety compliance for nonuniform field exposures is discussed using coupling factor concepts. The coupling factor, which is defined in the International Electrotechnical Commission 62311 standard, is extended to consider the effects of harmonics and also to apply to the specific absorption rate (for...

journal_title：Physics in medicine and biology

authors： Sunohara T,Hirata A,Laakso I,De Santis V,Onishi T

更新日期：2015-10-21 00:00:00

abstract：:Nuclear emulsions of the Ilford K series, exposed to X-rays from 15 to 150 kVp and systematically underdeveloped, exhibit supralinear blackness--exposure curves ranging from 1- to 4-hit in character, and whose shape is the same at all excitation voltages. Processing can be so adjusted that the curve shape is well repr...

journal_title：Physics in medicine and biology

authors： Katz R,Pennington EC

更新日期：1978-11-01 00:00:00

abstract：:A recently described, computer aided method of attenuation analysis has been applied to free-air chamber measurements of the attenuation by up to 30mm A1 of the exposure rate of a narrow beam of X-radiation excited at a thick W target in a Be window tube by constant potentials of 60, 80, 100, 120 and 140 kV. It has ...

journal_title：Physics in medicine and biology

authors： Soole BW

更新日期：1977-03-01 00:00:00

abstract：:[(18)F]Fluorothymidine (FLT) is a cell proliferation marker that undergoes predominantly hepatic metabolism and therefore shows a high level of accumulation in the liver, as well as in rapidly proliferating tumours. Furthermore, the tracer's uptake is substantial in other organs including the heart. We present a nonli...

journal_title：Physics in medicine and biology

authors： Gray KR,Contractor KB,Kenny LM,Al-Nahhas A,Shousha S,Stebbing J,Wasan HS,Coombes RC,Aboagye EO,Turkheimer FE,Rosso L

更新日期：2010-02-07 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：:A number of heating sources are available for minimally invasive thermal therapy of tumours. The purpose of this work was to compare, theoretically, the heating characteristics of interstitial microwave, laser and ultrasound sources in three tissue sites: breast, brain and liver. Using a numerical method, the heating ...

journal_title：Physics in medicine and biology

authors： Skinner MG,Iizuka MN,Kolios MC,Sherar MD

更新日期：1998-12-01 00:00:00

abstract：:In this work, five 4D image-guidance strategies (two population, an offline adaptive and two online strategies) were evaluated that compensated for both inter- and intra-fraction variability such as changes to the baseline tumour position and respiratory pattern. None of the strategies required active motion compensat...

journal_title：Physics in medicine and biology

authors： Hugo GD,Yan D,Liang J

更新日期：2007-01-07 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：:The rationale for multi-modality imaging is to integrate the strengths of different imaging technologies while reducing the shortcomings of an individual modality. The work presented here proposes a limited-field-of-view (LFOV) SPECT reconstruction technique that can be implemented on a multi-modality MR/SPECT system ...

journal_title：Physics in medicine and biology

authors： Lee KS,Roeck WW,Gullberg GT,Nalcioglu O

更新日期：2011-02-07 00:00:00

abstract：:A theoretical analysis is presented of the biologically effective dose of the solar long wave ultraviolet radiation (UVA) received by patients who are being treated for psoriasis by oral psoralen photochemotherapy. It is shown that patients treated during the summer months in the UK may well receive a UV dose which is...

journal_title：Physics in medicine and biology

authors： Diffey BL

更新日期：1981-11-01 00:00:00

abstract：:This paper reports a theoretical study on the distribution of blood flow in the human cardiovascular system when one or more blood vessels are affected by stenosis. The analysis employs a mathematical model of the entire system based on the finite element method. The arterial-venous network is represented by a large n...

journal_title：Physics in medicine and biology

authors： Sud VK,Srinivasan RS,Charles JB,Bungo MW

更新日期：1993-03-01 00:00:00

abstract：:A variable Jacobian and weighted backprojection algorithm, used for medical CT, was adapted to perform CT reconstructions on data obtained with a dental panoramic x-ray unit. A detector array, fitted to the unit for the purpose of acquiring digital panoramic radiographs, was used to collect the data. Compensations wer...

journal_title：Physics in medicine and biology

authors： Lee MD,Waggener RG,McDavid WD,Dove SB,Welander U,Tronje G

更新日期：1992-12-01 00:00:00

abstract：:The dynamic magnetization of immobilized spherical single-domain magnetic nanoparticles (MNPs) with uniaxial or cubic magnetocrystalline anisotropy was studied computationally by executing simulations based on the Landau-Lifshitz-Gilbert (LLG) equation. For situations when a static magnetic field was suddenly applied ...

journal_title：Physics in medicine and biology

authors： Zhao Z,Garraud N,Arnold DP,Rinaldi C

更新日期：2020-01-17 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：:The elastic and hyperelastic properties of biological soft tissues have been of interest to the medical community. There are several biomedical applications where parameters characterizing such properties are critical for a reliable clinical outcome. These applications include surgery planning, needle biopsy and brach...

journal_title：Physics in medicine and biology

authors： O'Hagan JJ,Samani A

更新日期：2009-04-21 00:00:00

abstract：:Permanent in vivo verification of IMRT photon beam profiles by a radiation detector with spatial resolution, positioned on the radiation entrance side of the patient, has not been clinically available so far. In this work we present the DAVID system, which is able to perform this quality assurance measurement while th...

journal_title：Physics in medicine and biology

authors： Poppe B,Thieke C,Beyer D,Kollhoff R,Djouguela A,Rühmann A,Willborn KC,Harder D

更新日期：2006-03-07 00:00:00

abstract：:An acardiac twin is a severely malformed monochorionic twin fetus that lacks most organs, particularly a heart. It grows during pregnancy, because it is perfused by its developmentally normal co-twin (called the pump twin) via a set of placental arterioarterial and venovenous anastomoses. The pump twin dies intrauteri...

journal_title：Physics in medicine and biology

authors： Umur A,van Gemert MJ,van den Wijngaard JP,Ross MG,Nikkels PG

更新日期：2004-07-21 00:00:00

abstract：:This work compared the impact of x-ray tube performance and automatic dose rate control (ADRC) parameter selection on system imaging efficiency of two Siemens angiography systems: a Siemens Megalix x-ray tube installed on an Artis Zee system (denoted 'MEGALIX') and a newer generation Gigalix x-ray tube installed on an...

journal_title：Physics in medicine and biology

authors： Dehairs M,Bosmans H,Marshall NW

更新日期：2020-11-24 00:00:00

abstract：:An ESTRO booklet and a report of the Netherlands Commission on Radiation Dosimetry have been published recently describing empirical methods for monitor unit (MU) calculations in symmetrical high-energy photon beams. Both documents support the same basic ideas; firstly the separation of head scatter and volume scatter...

journal_title：Physics in medicine and biology

authors： Georg D

更新日期：1999-12-01 00:00:00

abstract：:This paper presents two methods for absorbed dose determination with ionization chambers at short distance from 60Co and 192Ir brachytherapy sources. The methods are modifications of the Bragg-Gray and large cavity principles given in the IAEA code of practice for high- and medium-energy photon beams. A non-uniformity...

journal_title：Physics in medicine and biology

authors： Tölli H,Johansson KA

更新日期：1998-11-01 00:00:00

abstract：:Radiochromic leuco crystal violet (LCV) micelle gel dosimeters are promising three-dimensional radiation dosimeters because of their spatial stability and suitability for optical readout. The effects of surfactant type and surfactant concentration on dose sensitivity of LCV micelle gels are tested, demonstrating that ...

journal_title：Physics in medicine and biology

authors： Nasr AT,Alexander K,Schreiner LJ,McAuley KB

更新日期：2015-06-21 00:00:00

abstract：:Intra-fractional motion is a concern during prostate radiation therapy, as it may cause deviations between planned and delivered radiation doses. Because accurate motion information during treatment delivery is critical to address dose deviation, we developed the projection marker matching method (PM3), a novel method...

journal_title：Physics in medicine and biology

authors： Chi Y,Rezaeian NH,Shen C,Zhou Y,Lu W,Yang M,Hannan R,Jia X

更新日期：2017-07-07 00:00:00