Experimental 3D dosimetry around a high-dose-rate clinical 192Ir source using a polyacrylamide gel (PAG) dosimeter.

abstract：:Effects of different scatter compensation methods incorporated in fully 3D iterative reconstruction are investigated. The methods are: (i) the inclusion of an 'ideal scatter estimate' (ISE); (ii) like (i) but with a noiseless scatter estimate (ISE-NF); (iii) incorporation of scatter in the point spread function during...

journal_title：Physics in medicine and biology

authors： Beekman FJ,Kamphuis C,Frey EC

更新日期：1997-08-01 00:00:00

abstract：:The usefulness of a direct detection scheme of the second harmonic (2h) overmodulated signal from irradiated alanine in EPR dosimetry was studied. For this purpose, a group of DL-alanine/paraffin cylindrical pellets was produced. The dosimeters were irradiated with a 60Co radiotherapy gamma source with doses of 0.05, ...

journal_title：Physics in medicine and biology

authors： Chen F,Graeff CF,Baffa O

更新日期：2002-04-21 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：:Gel dosimetry based on magnetic resonance imaging (MRI) has previously been shown to provide verification of calculated dose distributions in soft tissue equivalent homogeneous phantoms. This study demonstrates how measurements of dose distribution can also be achieved in a phantom containing porous, lung-equivalent, ...

journal_title：Physics in medicine and biology

authors： Olberg S,Skretting A,Bruland O,Olsen DR

更新日期：2000-10-01 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：:The purpose of this paper for four-dimensional (4D) computed tomography (CT) is threefold. (1) A new spatiotemporal model is presented from the matrix perspective with the row dimension in space and the column dimension in time, namely the robust PCA (principal component analysis)-based 4D CT model. That is, instead o...

journal_title：Physics in medicine and biology

authors： Gao H,Cai JF,Shen Z,Zhao H

更新日期：2011-06-07 00:00:00

abstract：:Intravascular coronary thermography is a method that may detect vulnerable, atherosclerotic plaques and is currently evaluated in a clinical setting. Active macrophages or enzymatic heat releasing processes in vulnerable plaques may act as heat sources. To better understand the parameters of influence on thermographic...

journal_title：Physics in medicine and biology

authors： ten Have AG,Gijsen FJ,Wentzel JJ,Slager CJ,van der Steen AF

更新日期：2004-10-07 00:00:00

abstract：:In the real-time tumor-tracking radiotherapy system, fluoroscopy is used to determine the real-time position of internal fiducial markers. The pattern recognition score (PRS) ranging from 0 to 100 is computed by a template pattern matching technique in order to determine the marker position on the fluoroscopic image. ...

journal_title：Physics in medicine and biology

authors： Miyamoto N,Ishikawa M,Bengua G,Sutherland K,Suzuki R,Kimura S,Shimizu S,Onimaru R,Shirato H

更新日期：2011-08-07 00:00:00

abstract：:Online proton range/dose verification based on measurements of proton-induced positron emitters is a promising strategy for quality assurance in proton therapy. Because of the nonlinear correlation between the dose distribution and the activity distribution of positron emitters, we aim to establish their relationship ...

journal_title：Physics in medicine and biology

authors： Liu C,Li Z,Hu W,Xing L,Peng H

更新日期：2019-09-04 00:00:00

abstract：:This paper presents a description of tests carried out to compare the behaviour of five algorithms in inverse radiation therapy planning: (1) The Dynamically Penalized Likelihood (DPL), an algorithm based on statistical estimation theory; (2) an accelerated version of the same algorithm: (3) a new fast adaptive simula...

journal_title：Physics in medicine and biology

authors： Llacer J,Solberg TD,Promberger C

更新日期：2001-10-01 00:00:00

abstract：:A water calorimeter has been used for the direct measurement of absorbed dose to water in a d(15) + Be neutron beam. The absorbed dose measured with the calorimeter was compared with that measured with an Exradin ionisation chamber, constructed of A-150 plastic. The doses measured by the ionisation chamber were calcul...

journal_title：Physics in medicine and biology

authors： Galloway G,Greening JR,Williams JR

更新日期：1986-04-01 00:00:00

abstract：:Heterogeneity corrections for radiotherapy dose calculations are based on the electron density of the disturbing heterogeneity. However, when CT planning a radiotherapy treatment, where metallic hip implants are present, considerable artefacts are seen in the images. Often, an additional problem arises whereby no info...

journal_title：Physics in medicine and biology

authors： Coolens C,Childs PJ

更新日期：2003-06-07 00:00:00

abstract：:We are developing a dedicated, combined breast positron emission tomography (PET)-tomosynthesis scanner. Both the PET and digital breast tomosynthesis (DBT) scanners are integrated in a single gantry to provide spatially co-registered 3D PET-tomosynthesis images. The DBT image will be used to identify the breast bound...

journal_title：Physics in medicine and biology

authors： Krishnamoorthy S,Vent T,Barufaldi B,Maidment ADA,Karp JS,Surti S

更新日期：2020-10-28 00:00:00

abstract：:The trend towards conformal, intensity modulated radiotherapy treatments has established the need for a true integrating dosimeter. In traditional radiotherapy, radiographic film dosimetry is commonly used. The accuracy and reproducibility of film optical density as an indicator of dose is influenced by several variab...

journal_title：Physics in medicine and biology

authors： Suchowerska N,Hoban P,Butson M,Davison A,Metcalfe P

更新日期：2001-05-01 00:00:00

abstract：:Enabling automated pipelines, image analysis and big data methodology in cancer clinics requires thorough understanding of the data. Automated quality assurance steps could improve the efficiency and robustness of these methods by verifying possible data biases. In particular, in head and neck (H&N) computed-tomograph...

journal_title：Physics in medicine and biology

authors： Welch ML,McIntosh C,Purdie TG,Wee L,Traverso A,Dekker A,Haibe-Kains B,Jaffray DA

更新日期：2020-01-10 00:00:00

abstract：:This work presents a Monte Carlo model of Leksell Gamma Knife Perfexion as well as the main parameters of the dose distribution in the standard phantom obtained using this model. The model is developed in the Geant4 simulation toolkit in a modular way which enables its reuse in other Perfexion studies. Large phase spa...

journal_title：Physics in medicine and biology

authors： Pipek J,Novotný J,Novotný J,Kozubíková P

更新日期：2014-12-21 00:00:00

abstract：:Optimization-based algorithms for image reconstruction in multispectral (or photon-counting) computed tomography (MCT) remains a topic of active research. The challenge of optimization-based image reconstruction in MCT stems from the inherently non-linear data model that can lead to a non-convex optimization program f...

journal_title：Physics in medicine and biology

authors： Chen B,Zhang Z,Sidky EY,Xia D,Pan X

更新日期：2017-11-02 00:00:00

abstract：:To evaluate a commercial synthetic CT (syn-CT) software for use in prostate radiotherapy. Twenty-five prostate patients underwent CT and MR simulation scans in treatment position on a 3T MR scanner. A commercially available MR protocol was used that included a T2w turbo spin-echo sequence for soft-tissue contrast and ...

journal_title：Physics in medicine and biology

authors： Tyagi N,Fontenla S,Zhang J,Cloutier M,Kadbi M,Mechalakos J,Zelefsky M,Deasy J,Hunt M

更新日期：2017-04-21 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：:Four dimensional cone beam computed tomography (4DCBCT) uses a constant gantry speed and imaging frequency that are independent of the patient's breathing rate. Using a technique called respiratory motion guided 4DCBCT (RMG-4DCBCT), we have previously demonstrated that by varying the gantry speed and imaging frequency...

journal_title：Physics in medicine and biology

authors： O'Brien RT,Stankovic U,Sonke JJ,Keall PJ

更新日期：2017-06-07 00:00:00

abstract：:We are developing a three-dimensional (3D) position-sensitive detector with isotropic spatial resolution, the X'tal cube. Originally, our design consisted of a crystal block for which all six surfaces were covered with arrays of multi-pixel photon counters (MPPCs). In this paper, we examined the feasibility of reducin...

journal_title：Physics in medicine and biology

authors： Hirano Y,Inadama N,Yoshida E,Nishikido F,Murayama H,Watanabe M,Yamaya T

更新日期：2013-03-07 00:00:00

abstract：:Grating-based x-ray phase-contrast imaging provides three simultaneous image channels originating from a single image acquisition. While the phase signal provides direct access to the electron density in tomography, there is additional information on sub-resolutional structural information which is called dark-field s...

journal_title：Physics in medicine and biology

authors： Braig EM,Pfeiffer D,Willner M,Sellerer T,Taphorn K,Petrich C,Scholz J,Petzold L,Birnbacher L,Dierolf M,Pfeiffer F,Herzen J

更新日期：2020-09-18 00:00:00

abstract：:Scattered doses, e.g. neutron doses in proton therapy, are of concern in radiation therapy. Although measured data are the gold standard, Monte Carlo simulations allow a more realistic consideration of patient anatomy via whole-body phantoms. When calculating neutron doses with Monte Carlo techniques, the dose can be ...

journal_title：Physics in medicine and biology

authors： Jarlskog CZ,Paganetti H

更新日期：2008-09-07 00:00:00

abstract：:Effective use of the [Formula: see text] decay chain in targeted internal radioimmunotherapy requires the retention of both [Formula: see text] and progeny isotopes at the target site. Imaging-based pharmacokinetic tests of these pharmaceuticals must therefore separately yet simultaneously image multiple isotopes that...

journal_title：Physics in medicine and biology

authors： Robertson AKH,Ramogida CF,Rodríguez-Rodríguez C,Blinder S,Kunz P,Sossi V,Schaffer P

更新日期：2017-06-07 00:00:00

abstract：:Respiratory motion can blur the tomographic reconstruction of positron emission tomography or single-photon emission computed tomography (SPECT) images, which subsequently impair quantitative measurements, e.g. in the upper abdomen area. Respiratory signal phase-based gated reconstruction addresses this problem, but d...

journal_title：Physics in medicine and biology

authors： Breuilly M,Malandain G,Guglielmi J,Marsault R,Pourcher T,Franken PR,Darcourt J

更新日期：2013-04-21 00:00:00

abstract：:A full-field speckle interferometry method for non-contact and prospectively high speed Photoacoustic Tomography is introduced and evaluated as proof of concept. Thermoelastic pressure induced changes of the objects topography are acquired in a repetitive mode without any physical contact to the object. In order to ob...

journal_title：Physics in medicine and biology

authors： Horstmann J,Spahr H,Buj C,Münter M,Brinkmann R

更新日期：2015-05-21 00:00:00

abstract：:A 4D ordered-subsets maximum a posteriori (OSMAP) algorithm for dynamic SPECT is described which uses a temporal prior that constrains each voxel's behaviour in time to conform to a compartmental model. No a priori limitations on kinetic parameters are applied; rather, the parameter estimates evolve as the algorithm i...

journal_title：Physics in medicine and biology

authors： Kadrmas DJ,Gullberg GT

更新日期：2001-05-01 00:00:00

abstract：:Finding fluence maps for intensity-modulated radiation therapy (IMRT) can be formulated as a multi-criteria optimization problem for which Pareto optimal treatment plans exist. To account for the dose-per-fraction effect of fractionated IMRT, it is desirable to exploit radiobiological treatment plan evaluation criteri...

journal_title：Physics in medicine and biology

authors： Hoffmann AL,den Hertog D,Siem AY,Kaanders JH,Huizenga H

更新日期：2008-11-21 00:00:00

abstract：:Ultrasound shock wave therapy is increasingly used for non-invasive surgery. It requires the focusing of very high pressure amplitude in precisely controlled focal spots. In transcostal therapy of the heart or the liver, the high impedance mismatch between the bones and surrounding tissues gives rise to strong aberrat...

journal_title：Physics in medicine and biology

authors： Robin J,Simon A,Arnal B,Tanter M,Pernot M

更新日期：2018-09-06 00:00:00

abstract：:We report the first experimental soft-tissue phase-contrast tomography results using a conventional x-ray tube source, with a millimeter-sized focal spot. The setup is based on a Talbot-Lau grating interferometer operated at a mean energy of 28 keV. We present three-dimensional ex vivo images of a chicken heart sample...

journal_title：Physics in medicine and biology

authors： Bech M,Jensen TH,Feidenhans'l R,Bunk O,David C,Pfeiffer F

更新日期：2009-05-07 00:00:00