The distribution of trace elements Ca, Fe, Cu and Zn and the determination of copper oxidation state in breast tumour tissue using muSRXRF and muXANES.

abstract：:Treatment plans optimized for intensity modulated proton therapy (IMPT) may be sensitive to range variations. The dose distribution may deteriorate substantially when the actual range of a pencil beam does not match the assumed range. We present two treatment planning concepts for IMPT which incorporate range uncertai...

journal_title：Physics in medicine and biology

authors： Unkelbach J,Chan TC,Bortfeld T

更新日期：2007-05-21 00:00:00

abstract：:Multileaf collimators (MLCs) have been in clinical use for many years and meanwhile are commonly used to deliver intensity-modulated radiotherapy (IMRT) beams. For this purpose it is important to know their dosimetric properties precisely, one of them being inter- and intraleaf leakage. The Siemens 160 MLC features a ...

journal_title：Physics in medicine and biology

authors： Klüter S,Sroka-Perez G,Schubert K,Debus J

更新日期：2011-01-21 00:00:00

abstract：:Range verification in proton therapy is a critical quality assurance task. We studied the feasibility of online range verification based on proton-induced acoustic signals, using a bidirectional long-short-term-memory recurrent neural network and various signal processing techniques. Dose distribution of 1D pencil pro...

journal_title：Physics in medicine and biology

authors： Yao S,Hu Z,Zhang X,Lou E,Liang Z,Wang Y,Peng H

更新日期：2020-11-05 00:00:00

abstract：:Recently, the initial 2D physical characterization of a small-diameter positron emission tomograph, designed specifically for scanning of small laboratory animals, was reported. The physical characteristics of the tomograph operating in 3D mode have now been measured and compared to those obtained in 2D mode. In 3D, t...

journal_title：Physics in medicine and biology

authors： Bloomfield PM,Myers R,Hume SP,Spinks TJ,Lammertsma AA,Jones T

更新日期：1997-02-01 00:00:00

abstract：:This work is a follow-up study for a recently-proposed 3D radiochromic gel dosimeter that contains a tetrazolium salt and a physical gel matrix made of poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (Pluronic F-127). Several tetrazolium salts were examined in this work, including tetrazoli...

journal_title：Physics in medicine and biology

authors： Kwiatos K,Maras P,Kadlubowski S,Stempień Z,Dudek M,Kozicki M

更新日期：2018-05-04 00:00:00

abstract：:Target motion is one of the major limitations of each high precision radiation therapy. Using advanced active beam delivery techniques, such as the magnetic raster scanning system for particle irradiation, the interplay between time-dependent beam and target position heavily distorts the applied dose distribution. Thi...

journal_title：Physics in medicine and biology

authors： Li Q,Groezinger SO,Haberer T,Rietzel E,Kraft G

更新日期：2004-07-21 00:00:00

abstract：:Developments in positron emission tomography (PET) technology have resulted in systems with finer detector elements designed to further improve spatial resolution. However, there is a limit to what extent reducing detector element size will improve spatial resolution in PET. The spatial resolution of PET imaging is li...

journal_title：Physics in medicine and biology

authors： Levin CS,Hoffman EJ

更新日期：1999-03-01 00:00:00

abstract：:Today, new single photon emission computed tomography (SPECT) reconstruction techniques rely on accurate Monte Carlo (MC) simulations to optimize reconstructed images. However, existing MC scintillation camera models which usually include an accurate description of the collimator and crystal, lack correct implementati...

journal_title：Physics in medicine and biology

authors： Rault E,Staelens S,Van Holen R,De Beenhouwer J,Vandenberghe S

更新日期：2011-01-07 00:00:00

abstract：:Accurate scatter correction is especially important for high-resolution 3D positron emission tomographies (PETs) such as high-resolution research tomograph (HRRT) due to large scatter fraction in the data. To address this problem, a fully 3D iterative scatter-corrected ordered subset expectation maximization (OSEM) in...

journal_title：Physics in medicine and biology

authors： Kim KS,Ye JC

更新日期：2011-08-07 00:00:00

abstract：:Measurements of standardized uptake values (SUV) can vary due to many causes, including respiratory motion. Various methodologies have been introduced to correct for motion in PET, with quiescent-period-gated (QPG) PET being the most popular approach. QPG has been shown to improve PET image quantification compared to ...

journal_title：Physics in medicine and biology

authors： Meier JG,Einstein SA,Diab RH,Erasmus LJ,Xu G,Mawlawi OR

更新日期：2019-05-16 00:00:00

abstract：:The treatment delivery time of intensity-modulated radiation therapy (IMRT) with a multileaf collimator (MLC) is generally longer than that of conventional radiotherapy. In theory, removing the flattening filter from the treatment head may reduce the beam-on time by enhancing the output dose rate, and then reduce the ...

journal_title：Physics in medicine and biology

authors： Fu W,Dai J,Hu Y,Han D,Song Y

更新日期：2004-04-21 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：:W (the average energy to form an ion pair) for 5.4 MeV 241Am alpha particles in a Rossi-type tissue-equivalent (TE) gas, argon and methane was determined to an accuracy better than 0.2% using a new automated data handling system. A vibrating reed electrometer and current digitiser were used to measure the current prod...

journal_title：Physics in medicine and biology

authors： Krieger GL,Baum JW,Varma MN,Beach JL

更新日期：1979-03-01 00:00:00

abstract：:The purpose of this study was to evaluate the impact of numerical errors caused by the floating point representation of real numbers in a GPU-based Monte Carlo code used for dose calculation in radiation oncology, and to identify situations where this type of error arises. The program used as a benchmark was bGPUMCD. ...

journal_title：Physics in medicine and biology

authors： Magnoux V,Ozell B,Bonenfant É,Després P

更新日期：2015-07-07 00:00:00

abstract：:The aim of this work is to evaluate dosimetric accuracy of a new treatment modality, HybridArc, in iPlan RT Dose 4.5 (BrainLAB, Feldkirchen, Germany) using a four-dimensional diode array (ArcCHECK, Sun Nuclear Corporation, Melbourne, USA). HybridArc is able to enhance dynamic conformal arcs with inversely planned elem...

journal_title：Physics in medicine and biology

authors： Petoukhova AL,van Egmond J,Eenink MG,Wiggenraad RG,van Santvoort JP

更新日期：2011-08-21 00:00:00

abstract：:The purpose of this study was to derive a complete set of correction and perturbation factors for output factors (OF) and dose profiles. Modern small field detectors were investigated including a plastic scintillator (Exradin W1, SI), a liquid ionization chamber (microLion 31018, PTW), an unshielded diode (Exradin D1V...

journal_title：Physics in medicine and biology

authors： Papaconstadopoulos P,Tessier F,Seuntjens J

更新日期：2014-10-07 00:00:00

abstract：:Many of the inadequacies of the system presently used for surveying environments containing penetrating radiation stem from the impossibility of defining a radiation parameter which is additive, measurable and closely related to peak dose equivalent in the body. Many of the present conceptual difficulties would be eli...

journal_title：Physics in medicine and biology

authors： Harvey JR

更新日期：1975-11-01 00:00:00

abstract：:This paper presents a compressed sensing (CS)-inspired reconstruction method for limited-angle computed tomography (CT). Currently, CS-inspired CT reconstructions are often performed by minimizing the total variation (TV) of a CT image subject to data consistency. A key to obtaining high image quality is to optimize t...

journal_title：Physics in medicine and biology

authors： Chen Z,Jin X,Li L,Wang G

更新日期：2013-04-07 00:00:00

abstract：:Recent measurements of differential elastic and inelastic neutron scattering from oxygen, nitrogen and calcium at 18 less than En less than 26 MeV are presented and analysed in terms of the optical model. These data, together with earlier measurements of scattering and total cross sections, are used to construct model...

journal_title：Physics in medicine and biology

authors： Islam MS,Finlay RW,Petler JS,Rapaport J,Alarcon R,Wierzbicki J

更新日期：1988-03-01 00:00:00

abstract：:We investigate an optimization-based reconstruction, with an emphasis on image-artifact reduction, from data collected in C-arm cone-beam computed tomography (CBCT) employed in image-guided interventional procedures. In the study, an image to be reconstructed is formulated as a solution to a convex optimization progra...

journal_title：Physics in medicine and biology

authors： Xia D,Langan DA,Solomon SB,Zhang Z,Chen B,Lai H,Sidky EY,Pan X

更新日期：2016-10-21 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：:We model the heterogeneous response to radiation of multicellular tumour spheroids assuming position- and volume-dependent radiosensitivity. We propose a method to calculate the overall radiosensitivity parameters to obtain the surviving fraction of tumours. A mathematical model of a spherical tumour with a hypoxic co...

journal_title：Physics in medicine and biology

authors： Horas JA,Olguin OR,Rizzotto MG

更新日期：2005-04-21 00:00:00

abstract：:Rotational coronary angiography provides a multitude of x-ray projections of the contrast agent enhanced coronary arteries along a given trajectory with parallel ECG recording. These data can be used to derive motion information of the coronary arteries including vessel displacement and pulsation. In this paper, a ful...

journal_title：Physics in medicine and biology

authors： Jandt U,Schäfer D,Grass M,Rasche V

更新日期：2009-01-07 00:00:00

abstract：:For plane-parallel chambers used in electron dosimetry, modern dosimetry protocols recommend a cross-calibration against a calibrated cylindrical chamber. The rationale for this is the unacceptably large (up to 3-4%) chamber-to-chamber variations of the perturbation factors (pwall)Co, which have been reported for plan...

journal_title：Physics in medicine and biology

authors： Kapsch RP,Bruggmoser G,Christ G,Dohm OS,Hartmann GH,Schüle E

更新日期：2007-12-07 00:00:00

abstract：:Iterative image reconstruction algorithms have the potential to produce low noise images. Early stopping of the iteration process is problematic because some features of the image may converge slowly. On the other hand, there may be noise build-up with increased number of iterations. Therefore, we examined the stabili...

journal_title：Physics in medicine and biology

authors： Chlewicki W,Hermansen F,Hansen SB

更新日期：2004-10-21 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：:Registration of different imaging modalities such as CT, MRI, functional MRI (fMRI), positron (PET) and single photon (SPECT) emission tomography is used in many clinical applications. Determining the quality of any automatic registration procedure has been a challenging part because no gold standard is available to e...

journal_title：Physics in medicine and biology

authors： Ceylan C,van der Heide UA,Bol GH,Lagendijk JJ,Kotte AN

更新日期：2005-05-21 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：:3D breast modelling for 2D and 3D breast x-ray imaging would benefit from the availability of digital and physical phantoms that reproduce accurately the complexity of the breast anatomy. While a number of groups have produced digital phantoms with increasing level of complexity, physical phantoms reproducing that sof...

journal_title：Physics in medicine and biology

authors： Esposito G,Mettivier G,Bliznakova K,Bliznakov Z,Bosmans H,Bravin A,Buliev I,Di Lillo F,Ivanov D,Minutillo M,Sarno A,Vignero J,Russo P

更新日期：2019-03-27 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