Cadmium in man measured in vivo by x-ray fluorescence analysis.

abstract：:Using conventional scintillation detection, the fundamental limit in positron emission tomography (PET) time resolution is strongly dependent on the inherent temporal variances generated during the scintillation process, yielding an intrinsic physical limit for the coincidence time resolution of around 100 ps. On the ...

journal_title：Physics in medicine and biology

authors： Tao L,Daghighian HM,Levin CS

更新日期：2016-11-07 00:00:00

abstract：:Recently, there has been an increased interest in flattening-filter-free (FFF) linear accelerators. Removal of the filter results in available dose rates up to 24 Gy min(-1) (for nominal energy 10 MV in depth of maximum dose, a source-surface distance of 100 cm and a field size of 10×10 cm2). To guarantee accurate rel...

journal_title：Physics in medicine and biology

authors： Lang S,Hrbacek J,Leong A,Klöck S

更新日期：2012-05-07 00:00:00

abstract：:Near-infrared fluorescence optical imaging has the unique opportunity of differentiating diseased lesions from normal lesions based upon environmentally indicated changes in the lifetime of a fluorescent imaging agent. In this paper, we demonstrate three-dimensional lifetime tomography using the gradient-based penalty...

journal_title：Physics in medicine and biology

authors： Roy R,Godavarty A,Sevick-Muraca EM

更新日期：2007-07-21 00:00:00

abstract：:The objective of this study was the determination of the thermal regulatory and the thermal breakdown thresholds for in-tube restrained B6C3F1 and NMRI mice exposed to radiofrequency electromagnetic fields at 905 MHz. Different levels of the whole-body averaged specific absorption rate (SAR = 0, 2, 5, 7.2, 10, 12.6 an...

journal_title：Physics in medicine and biology

authors： Ebert S,Eom SJ,Schuderer J,Apostel U,Tillmann T,Dasenbrock C,Kuster N

更新日期：2005-11-07 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：:With the development of laser technology, laser-driven proton acceleration provides a new method for proton tumor therapy. However, it has not been applied in practice because of the wide and decreasing energy spectrum of laser-accelerated proton beams. In this paper, we propose an analytical model to reconstruct the ...

journal_title：Physics in medicine and biology

authors： Tao L,Zhu K,Zhu J,Xu X,Lin C,Ma W,Lu H,Zhao Y,Lu Y,Chen JE,Yan X

更新日期：2017-07-07 00:00:00

abstract：:This study examines the effectiveness of a single, first-order Arrhenius process in accurately modelling the thermally induced changes in the optical properties, particularly the reduced scattering coefficient, mu(s)', and the absorption coefficient, mu(a), of ex vivo rat prostate. Recent work has shown that mu(s)' ca...

journal_title：Physics in medicine and biology

authors： Skinner MG,Everts S,Reid AD,Vitkin IA,Lilge L,Sherar MD

更新日期：2000-05-01 00:00:00

abstract：:For renal dynamic studies, the COST B2 hybrid phantom is an example of an artificially created software phantom. Although this phantom is useful, it is not possible to implement the phantom in a self-consistent fashion to produce, for example, a collection of tracer in the bladder which is related to the flow from the...

journal_title：Physics in medicine and biology

authors： Houston AS,Sampson WF,Jose RM,Boyce JF

更新日期：1999-02-01 00:00:00

abstract：:We have numerically modelled the thermal effects of yellow (577 or 578 nm) light illumination on the ectatic blood vessels of port wine stains. We investigated the effect of the laser treatment parameters of light irradiance and illumination time on the extent of coagulation (coagulation thickness) of the endothelial ...

journal_title：Physics in medicine and biology

authors： Pickering JW,Butler PH,Ring BJ,Walker EP

更新日期：1989-09-01 00:00:00

abstract：:Brain stereotactic radiosurgery (SRS) treatments require multiple quality assurance (QA) procedures to ensure accurate and precise treatment delivery. As single-isocenter multitarget SRS treatments become more popular, the quantification of off-axis accuracy of the linear accelerator is crucial. In this study, a novel...

journal_title：Physics in medicine and biology

authors： Capaldi DPI,Skinner LB,Dubrowski P,Yu AS

更新日期：2020-06-10 00:00:00

abstract：:All radiation therapy treatment planning relies on accurate dose calculation. Uncertainties in dosimetric prediction can significantly degrade an otherwise optimal plan. In this work, we introduce a robust optimization method which handles dosimetric errors and warrants for high-quality IMRT plans. Unlike other dose e...

journal_title：Physics in medicine and biology

authors： Nohadani O,Seco J,Martin BC,Bortfeld T

更新日期：2009-06-07 00:00:00

abstract：:Contrast enhanced ultrasound (CEUS) and dynamic contrast enhanced ultrasound (DCE-US) can be used to provide information about the vasculature aiding diagnosis and monitoring of a number of pathologies including cancer. In the development of a CEUS imaging system, there are many choices to be made, such as whether to ...

journal_title：Physics in medicine and biology

authors： Moghimirad E,Bamber J,Harris E

更新日期：2019-04-23 00:00:00

abstract：:Modern effort in radiotherapy to address the challenges of tumor localization and motion has led to the development of MRI guided radiotherapy technologies. Accurate dose calculations must properly account for the effects of the MRI magnetic fields. Previous work has investigated the accuracy of a deterministic linear...

journal_title：Physics in medicine and biology

authors： Zelyak O,Fallone BG,St-Aubin J

更新日期：2017-12-14 00:00:00

abstract：:A micro-multileaf collimator (microMLC) for stereotactic radiosurgery is used for determination of the spatial intensity distribution of the photon source of a linear accelerator. The method is based on grid field dose measurements using film dosimetry and is easy to perform. Since the microMLC does not allow 'direct'...

journal_title：Physics in medicine and biology

authors： Treuer H,Hoevels M,Luyken K,Hunsche S,Kocher M,Müller RP,Sturm V

更新日期：2003-08-07 00:00:00

abstract：:The objective of this work is to test analytical models to calculate the luminescence efficiency of Al(2)O(3):C optically stimulated luminescence detectors (OSLDs) exposed to heavy charged particles with energies relevant to space dosimetry and particle therapy. We used the track structure model to obtain an analytica...

journal_title：Physics in medicine and biology

authors： Sawakuchi GO,Yukihara EG

更新日期：2012-01-21 00:00:00

abstract：:Ion beam radiotherapy exploits the finite range of ion beams and the increased dose deposition of ions toward the end of their range in material. This results in high dose conformation to the target region, which can be further increased using scanning ion beams. The standard method for patient-plan verification in io...

journal_title：Physics in medicine and biology

authors： Martišíková M,Brons S,Hesse BM,Jäkel O

更新日期：2013-03-21 00:00:00

abstract：:Accurate scatter correction is required to produce high-quality reconstructions of x-ray cone-beam computed tomography (CBCT) scans. This paper describes new scatter kernel superposition (SKS) algorithms for deconvolving scatter from projection data. The algorithms are designed to improve upon the conventional approac...

journal_title：Physics in medicine and biology

authors： Sun M,Star-Lack JM

更新日期：2010-11-21 00:00:00

abstract：:Beta emitting 106Ru-applicators are used to treat choroidal melanoma. In order to improve the accuracy and simplify the dosimetry of these applicators, the suitability of using a p-type silicon semiconductor detector has been investigated. The detector is calibrated in a low energy electron beam. An important property...

journal_title：Physics in medicine and biology

authors： Lax I

更新日期：1991-07-01 00:00:00

abstract：:The dielectric constant and conductivity of muscle, liver, spleen and kidney of cats in vivo and in situ immediately following the animal's death were measured at frequencies from 10 kHz to 100 MHz. A novel multi-ring capacitive sensor and a computer-controlled automatic network analyser (ANA) were employed. The resul...

journal_title：Physics in medicine and biology

authors： Surowiec A,Stuchly SS,Keaney M,Swarup A

更新日期：1986-08-01 00:00:00

abstract：:In situ and in vivo treatment plan verification and beam monitoring as well as dose control during heavy-ion tumour therapy can be performed in principle by measurements of range distributions of beta(+)-emitting nuclei by means of PET techniques. For this purpose the performance of different types of positron camera ...

journal_title：Physics in medicine and biology

authors： Pawelke J,Byars L,Enghardt W,Fromm WD,Geissel H,Hasch BG,Lauckner K,Manfrass P,Schardt D,Sobiella M

更新日期：1996-02-01 00:00:00

abstract：:Intraoperative x-ray radiography/fluoroscopy is commonly used to assess the placement of surgical devices in the operating room (e.g. spine pedicle screws), but qualitative interpretation can fail to reliably detect suboptimal delivery and/or breach of adjacent critical structures. We present a 3D-2D image registratio...

journal_title：Physics in medicine and biology

authors： Uneri A,De Silva T,Goerres J,Jacobson MW,Ketcha MD,Reaungamornrat S,Kleinszig G,Vogt S,Khanna AJ,Osgood GM,Wolinsky JP,Siewerdsen JH

更新日期：2017-04-21 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：:The purpose of this study was the evaluation of the impact of a variable relative biological effectiveness (RBE) compared to a constant RBE value of 1.1 in proton therapy prostate trials due to uncertainties in α/β ratio. Twenty patients receiving passive scattered proton therapy (PSPT) and fifteen patients receiving ...

journal_title：Physics in medicine and biology

authors： Marteinsdottir M,Paganetti H

更新日期：2019-06-05 00:00:00

abstract：:It has been demonstrated that gas-filled microbubble contrast agents, based on their volume changes, can serve as pressure probes in an MR field. It was recently reported that such an MR-based pressure measurement with microbubbles at 1.5 T must make use of microbubbles that have a volumetric magnetic susceptibility d...

journal_title：Physics in medicine and biology

authors： Dharmakumar R,Plewes DB,Wright GA

更新日期：2005-10-21 00:00:00

abstract：:In this work we present the first delivery of intensity modulated arc therapy on the Elekta Unity 1.5 T MR-linac. The machine's current IMRT based control system was modified suitably to enable dynamic delivery of radiation, for the purpose of exploring MRI-guided radiation therapy adaptation modes in a research setti...

journal_title：Physics in medicine and biology

authors： Kontaxis C,Woodhead PL,Bol GH,Lagendijk JJW,Raaymakers BW

更新日期：2020-12-23 00:00:00

abstract：:A computer program was developed to calculate both integral absorbed dose in a water phantom and entrance exposure, for the imaging of iodine contrast with x-ray intensifying screens. The effect of filtration of the x-ray beam on integral absorbed dose and entrance exposure was studied for 27 different filter material...

journal_title：Physics in medicine and biology

authors： Koedooder K,Venema HW

更新日期：1986-06-01 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：:The relative biological effectiveness (RBE) of protons varies with multiple physical and biological factors. Phenomenological RBE models have been developed to include such factors in the estimation of a variable RBE, in contrast to the clinically applied constant RBE of 1.1. In this study, eleven published phenomenol...

journal_title：Physics in medicine and biology

authors： Rørvik E,Fjæra LF,Dahle TJ,Dale JE,Engeseth GM,Stokkevåg CH,Thörnqvist S,Ytre-Hauge KS

更新日期：2018-09-13 00:00:00

abstract：:The possible use of fluorescence bronchoscopy for localization of bronchogenic tumours at the carcinoma in situ stage has been investigated. The target lesion is 80 micrometer thick with a mass of 250 microgram, containing 250 pg of haematoporphyrin derivative. The injected haematoporphyrin-derivative is preferentiall...

journal_title：Physics in medicine and biology

authors： Profio AE,Doiron DR

更新日期：1977-09-01 00:00:00

abstract：:A method was developed to quantify the intensity of tissue staining using a CCD (charge-coupled device) camera. Reflection spectra of NBT-stained (nitro-blue tetrazolium-stained) and unstained myocardium were recorded via fibre optics coupled to a CCD camera, connected to a microcomputer. The calculation of the intens...

journal_title：Physics in medicine and biology

authors： Schröder T,Koch G,Schnabel PA,Hering JP,Bretschneider HJ,Richter J,Hellige G

更新日期：1991-06-01 00:00:00