Radiation dose factors for alpha-emitters in osteons and some considerations on dose non-uniformity ratios and relative distribution factors.

abstract：:A comparative study was performed to reveal differences and relative figures of merit of seven different calculation algorithms for photon beams when applied to inhomogeneous media. The following algorithms were investigated: Varian Eclipse: the anisotropic analytical algorithm, and the pencil beam with modified Batho...

journal_title：Physics in medicine and biology

authors： Fogliata A,Vanetti E,Albers D,Brink C,Clivio A,Knöös T,Nicolini G,Cozzi L

更新日期：2007-03-07 00:00:00

abstract：:This is a proof of principle study on an algorithm for optimizing external beam radiotherapy in terms of both photon beamlet energy and fluence. This simultaneous beamlet energy and fluence optimization is denoted modulated photon radiotherapy (XMRT). XMRT is compared with single-energy intensity modulated radiotherap...

journal_title：Physics in medicine and biology

authors： McGeachy P,Villarreal-Barajas JE,Zinchenko Y,Khan R

更新日期：2016-02-21 00:00:00

abstract：:The function of the placenta is challenging to characterize and as a result is understudied, despite the growing awareness of the impact of the placental environment on human health and development. Medical imaging has the potential to improve our ability to screen for diseases associated with placental insufficiency,...

journal_title：Physics in medicine and biology

authors： Wu C,Bayer CL

更新日期：2018-07-09 00:00:00

abstract：:In this letter the authors highlight the presence of an error appearing in the discussion of the note 'The use of the Henyey-Greenstein phase function in Monte Carlo simulations in biomedical optics' previously published by them (Binzoni et al 2006 Phys. Med. Biol. 51 N313). In the light of this error, the discussion ...

journal_title：Physics in medicine and biology

authors： Binzoni T,Leung TS,Gandjbakhche AH,Rüfenacht D,Delpy DT

更新日期：2006-11-21 00:00:00

abstract：:RapidArc, recently released by Varian Medical Systems, is a novel extension of IMRT in which an optimized 3D dose distribution may be delivered in a single gantry rotation of 360 degrees or less. The purpose of this study was to investigate the accuracy of the analytical anisotropic algorithm (AAA), the sole algorithm...

journal_title：Physics in medicine and biology

authors： Gagne IM,Ansbacher W,Zavgorodni S,Popescu C,Beckham WA

更新日期：2008-12-21 00:00:00

abstract：:An algorithm is described for three-dimensional whole-body (3DWB) image reconstruction in positron emission tomography. For whole-body applications, improvements to the popular fixed-axial-acceptance-angle technique are achieved by combining axially adjacent projection data available with a long-axis data set. Time-co...

journal_title：Physics in medicine and biology

authors： Cutler PD,Xu M

更新日期：1996-08-01 00:00:00

abstract：:We present a new image reconstruction algorithm for helical cone-beam computed tomography (CT). This algorithm is designed for data collected at or near maximum pitch, and provides a theoretically exact and stable reconstruction while beneficially using all measured data. The main operations involved are a differentia...

journal_title：Physics in medicine and biology

authors： Schöndube H,Stierstorfer K,Noo F

更新日期：2009-08-07 00:00:00

abstract：:The 0.35 T 60Co MRIdian system (ViewRay Inc., Mountain View) has been in clinical use in our institution since May 2016. For quality assurance (QA) of dose delivery and end-to-end testing for this machine, a reliable dosimeter is required. However, it is possible that a magnetic field may cause perturbations to dosime...

journal_title：Physics in medicine and biology

authors： Barten DLJ,Hoffmans D,Palacios MA,Heukelom S,van Battum LJ

更新日期：2018-08-20 00:00:00

abstract：:Percutaneous coronary interventions are associated with increased radiation exposure compared to most radiological examinations. This prospective study aimed at (1) measuring entrance doses for all in-room personnel, (2) performing an assessment of patient effective dose and intracoronary doses, (3) investigating the ...

journal_title：Physics in medicine and biology

authors： Efstathopoulos EP,Makrygiannis SS,Kottou S,Karvouni E,Giazitzoglou E,Korovesis S,Tzanalaridou E,Raptou PD,Katritsis DG

更新日期：2003-09-21 00:00:00

abstract：:In the current work, EPR (electron paramagnetic resonance) dosimetry using alanine films (134 microm thick) was utilized for dose measurements in inhomogeneous phantoms irradiated with radiotherapy photon beams. The main phantom material was PMMA, while either Styrofoam or aluminium was introduced as an inhomogeneity....

journal_title：Physics in medicine and biology

authors： Osterås BH,Hole EO,Olsen DR,Malinen E

更新日期：2006-12-21 00:00:00

abstract：:Proton computed tomography (pCT) promises to reduce or even eliminate range uncertainties inherent in the conversion of Hounsfield units into relative stopping power (RSP) for proton therapy treatment planning. This is of particular interest for proton irradiation studies in animal models due to the high precision req...

journal_title：Physics in medicine and biology

authors： Meyer S,Bortfeldt J,Lämmer P,Englbrecht FS,Pinto M,Schnürle K,Würl M,Parodi K

更新日期：2020-08-13 00:00:00

abstract：:Subharmonic contrast imaging promises to improve ultrasound-imaging quality by taking advantage of an increased contrast to tissue signal. However, acoustic pressures beyond the subharmonic generation threshold using common ultrasound pulses may induce significant contrast microbubble destruction. In this work, a chir...

journal_title：Physics in medicine and biology

authors： Zhang D,Gong Y,Gong X,Liu Z,Tan K,Zheng H

更新日期：2007-09-21 00:00:00

abstract：:The use of liquid ionization chambers in radiotherapy has grown during the past few years. While for air ionization chambers the k(TP) correction for air mass density due to pressure and temperature variations is well known, less work has been done on the case of liquid ionization chambers, where there is still the ne...

journal_title：Physics in medicine and biology

authors： Gómez F,González-Castaño D,Díaz-Botana P,Pardo-Montero J

更新日期：2014-06-07 00:00:00

abstract：:An important challenge in real-world biomedical applications of x-ray phase contrast imaging (XPCI) techniques is the efficient use of the photon flux generated by an incoherent and polychromatic x-ray source. This efficiency can directly influence dose and exposure time and ideally should not affect the superior cont...

journal_title：Physics in medicine and biology

authors： Saghamanesh S,Aghamiri SM,Kamali-Asl A,Yashiro W

更新日期：2017-09-01 00:00:00

abstract：:Although the calculation of the surface average of the low-frequency current density distribution over a cross-section of 1 cm2 is required by ICNIRP guidelines, no reference averaging algorithm is indicated, neither in the ICNIRP guidelines nor in the Directive 2004/40/EC that is based on them. The lack of a general ...

journal_title：Physics in medicine and biology

authors： Zoppetti N,Andreuccetti D

更新日期：2009-08-07 00:00:00

abstract：:Electronic article surveillance (EAS) devices are widely used in most stores as anti-theft systems. In this work, the compliance with international guidelines in the human exposure to these devices is analysed by using the finite-difference time-domain (FDTD) method. Two sets of high resolution numerical phantoms of d...

journal_title：Physics in medicine and biology

authors： Martínez-Búrdalo M,Sanchis A,Martín A,Villar R

更新日期：2010-02-21 00:00:00

abstract：:As the use of radiofrequency (RF) electromagnetic (EM) fields has increased along with increased use of wireless communication, the possible related health risks have also been widely discussed. One safety aspect is the interaction of medical implants and RF devices like mobile phones. In the literature, effects on ac...

journal_title：Physics in medicine and biology

authors： Virtanen H,Keshvari J,Lappalainen R

更新日期：2007-03-07 00:00:00

abstract：:In electron beam dosimetry using parallel-plate chambers solid phantoms are sometimes necessary. To obtain the dose to water from the ionization obtained in the solid phantom, fluence correction factors and perturbation factors have to be applied. In this study fluence factors in a perturbation free geometry have been...

journal_title：Physics in medicine and biology

authors： Nilsson B,Montelius A,Andreo P,Johansson J

更新日期：1997-11-01 00:00:00

abstract：:A novel approach to read out radiochromic film was introduced recently by the manufacturer of GafChromic film. In this study, the performance of this triple-channel film dosimetry method was compared against the conventional single-red-channel film dosimetry procedure, with and without inclusion of a pre-irradiation (...

journal_title：Physics in medicine and biology

authors： van Hoof SJ,Granton PV,Landry G,Podesta M,Verhaegen F

更新日期：2012-07-07 00:00:00

abstract：:A detailed Monte Carlo model of a proton therapy treatment head was commissioned to simulate the delivery of small field proton treatments. Small fields are challenging in the planning and quality assurance process because of aperture scattering and dosimetric disequilibrium. Four patients with small fields used in al...

journal_title：Physics in medicine and biology

authors： Bednarz B,Daartz J,Paganetti H

更新日期：2010-12-21 00:00:00

abstract：:This work aims to develop a voxel-level dose prediction framework by integrating distance information between PTV and OARs, as well as image information, into a densely-connected network (DCNN). Firstly, a four-channel feature map, consisting of a PTV image, an OAR image, a CT image, and a distance image, is construct...

journal_title：Physics in medicine and biology

authors： Zhang J,Liu S,Yan H,Li T,Mao R,Liu J

更新日期：2020-10-21 00:00:00

abstract：:Two novel materials have been developed to simulate the dielectric properties of human muscle and fat at 1000 MHz. These materials, which are based on ethanediol set with gelatine, are easily made and have good mechanical properties. The complex permittivity, epsilon *, of each material was measured with an open-ended...

journal_title：Physics in medicine and biology

authors： Robinson MP,Richardson MJ,Green JL,Preece AW

更新日期：1991-12-01 00:00:00

abstract：:Respiratory gating based on external surrogates is performed in many clinics. We have developed a new technique for treatment verification using an electronic portal imaging device (EPID) in cine mode for gated 3D conformal therapy. Implanted radiopaque fiducial markers inside or near the target are required for this ...

journal_title：Physics in medicine and biology

authors： Berbeco RI,Neicu T,Rietzel E,Chen GT,Jiang SB

更新日期：2005-08-21 00:00:00

abstract：:Light propagation in a turbid medium is considered using the linear transport equation. The existence of a diffusion length is proved for the Henyey-Greenstein scattering kernel for all absorption ratios. Numerical methods are given that allow accurate computation of the diffusion coefficient quite easily. ...

journal_title：Physics in medicine and biology

authors： Sahni DC,Dahl EB,Sjöstrand NG

更新日期：2003-12-07 00:00:00

abstract：:Modern Monte Carlo codes allow for the calculation of ion chamber specific beam quality correction factors k(Q), which are needed for dosimetry in radiotherapy. While statistical (type A) uncertainties of the calculated data can be minimized sufficiently, the influence of systematic (type B) uncertainties is mostly un...

journal_title：Physics in medicine and biology

authors： Wulff J,Heverhagen JT,Zink K,Kawrakow I

更新日期：2010-08-21 00:00:00

abstract：:Radionuclides which decay by electron capture accompanied by Auger electron cascades, or by beta emission are thought to be excessively damaging when incorporated into the molecular structure of mammalian cell nuclei and thereby pose a radiation hazard which is not assessable by conventional dosimetry. Survival data, ...

journal_title：Physics in medicine and biology

authors： Younis AR,Watt DE

更新日期：1989-07-01 00:00:00

abstract：:We present the results of utilizing aligned anatomical information from CT images to locally adjust image smoothness during the reconstruction of three-dimensional (3D) whole-body positron emission tomography (PET) data. The ability of whole-body PET imaging to detect malignant neoplasms is becoming widely recognized....

journal_title：Physics in medicine and biology

authors： Comtat C,Kinahan PE,Fessler JA,Beyer T,Townsend DW,Defrise M,Michel C

更新日期：2002-01-07 00:00:00

abstract：:Radiobiological models for estimating normal tissue complication probability (NTCP) are increasingly used in order to quantify or optimize the clinical outcome of radiation therapy. A good NTCP model should fulfill at least the following two requirements: (a) it should predict the sigmoid shape of the corresponding do...

journal_title：Physics in medicine and biology

authors： Adamus-Górka M,Mavroidis P,Brahme A,Lind BK

更新日期：2008-11-21 00:00:00

abstract：:Beam tracking with scanned carbon ion radiotherapy achieves highly conformal target dose by steering carbon pencil beams to follow moving tumors using real-time magnetic deflection and range modulation. The purpose of this study was to evaluate the robustness of target dose coverage from beam tracking in light of posi...

journal_title：Physics in medicine and biology

authors： Eley JG,Newhauser WD,Richter D,Lüchtenborg R,Saito N,Bert C

更新日期：2015-02-21 00:00:00

abstract：:Determining accurate in vivo dosimetry in brachytherapy treatment with high dose gradients is challenging. Here we introduce, investigate, and characterize a novel in vivo dosimeter and readout technique with the potential to address this problem. A cylindrical (4 mm × 20 mm) tissue equivalent radiochromic dosimeter P...

journal_title：Physics in medicine and biology

authors： Vidovic AK,Juang T,Meltsner S,Adamovics J,Chino J,Steffey B,Craciunescu O,Oldham M

更新日期：2014-07-21 00:00:00