Task Group 284 Report: Magnetic Resonance Imaging Simulation in Radiotherapy: Considerations for Clinical Implementation, Optimization, and Quality Assurance.

abstract：:Transthoracic electrical impedance Z consists of a constant baseline component Z0 and the time variable component delta Z such that Z = Z0 + delta Z. The first time derivative of Z has a negative peak, the magnitude of which is (dZ/dt)min. Measurements of 170 volunteers show that (dZ/dt)min is a function of the consta...

journal_title：Medical physics

authors： Djordjevich L,Sadove MS

更新日期：1981-01-01 00:00:00

abstract：:Respiration can cause tumors in the thorax or abdomen to move by as much as 3 cm; this movement can adversely affect the planning and delivery of radiation treatment. Several techniques have been used to compensate for respiratory motion, but all have shortcomings. Manufacturers of computed tomography (CT) equipment h...

journal_title：Medical physics

authors： Fitzpatrick MJ,Starkschall G,Antolak JA,Fu J,Shukla H,Keall PJ,Klahr P,Mohan R

更新日期：2006-01-01 00:00:00

abstract：:High false-positive (FP) rate remains to be one of the major problems to be solved in CAD study because too many false-positively cued signals will potentially degrade the performance of detecting true-positive regions and increase the call-back rate in CAD environment. In this paper, we proposed a novel classificatio...

journal_title：Medical physics

authors： Li L,Zheng Y,Zhang L,Clark RA

更新日期：2001-02-01 00:00:00

abstract：:Numerical reconstruction of x-ray spectra from narrow-beam transmission data was tested with published spectra in the range from 45 to 100 kVp. Transmission curves were calculated from the spectra to simulate measured data. Spectra were reconstructed from these transmission curves with use of an iterative numerical an...

journal_title：Medical physics

authors： Huang PH,Chen TS,Kase KR

更新日期：1986-09-01 00:00:00

abstract：PURPOSE:Recently, brain tumor segmentation has made important progress. However, the quality of manual labels plays an important role in the performance, while in practice, it could vary greatly and in turn could substantially mislead the learning process and decrease the accuracy. We need to design a mechanism to comb...

journal_title：Medical physics

authors： Cheng G,Ji H,He L

更新日期：2020-09-24 00:00:00

abstract：PURPOSE:To develop a pharmacokinetic modelfree framework to analyze the dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) data for assessment of response of brain metastases to radiation therapy. METHODS:Twenty patients with 45 analyzable brain metastases had MRI scans prior to whole brain radiation thera...

journal_title：Medical physics

authors： Farjam R,Tsien CI,Lawrence TS,Cao Y

更新日期：2014-01-01 00:00:00

abstract：PURPOSE:Over the last four decades, Ocular Proton Therapy has been successfully used to treat patients affected by intraocular lesions. For this, treatment geometry verification is routinely performed using radiographic images to align a configuration of fiducial radiopaque markers implanted on the sclera outer surface...

journal_title：Medical physics

authors： Via R,Hennings F,Fattori G,Fassi A,Pica A,Lomax A,Weber DC,Baroni G,Hrbacek J

更新日期：2018-05-01 00:00:00

abstract：PURPOSE:State of the art to access radiofrequency (RF) heating near implants is computer modeling of the devices and solving Maxwell's equations for the specific setup. For a set of input parameters, a fixed result is obtained. This work presents a theoretical approach in the alternating current (ac) limit, which can p...

journal_title：Medical physics

authors： Ballweg V,Eibofner F,Graf H

更新日期：2011-10-01 00:00:00

abstract：PURPOSE:Currently, in clinical practice of intensity-modulated proton therapy (IMPT), the influence of the minimum monitor unit (MU) constraint is taken into account through postprocessing after the optimization is completed. This may degrade the plan quality and plan robustness. This study aims to mitigate the impact ...

journal_title：Medical physics

authors： Shan J,An Y,Bues M,Schild SE,Liu W

更新日期：2018-01-01 00:00:00

abstract：:When parallel-plate chambers are used for dosimetry in electron fields, the AAPM dosimetry protocol recommends a value of 1.0 for the replacement correction factor, P(repl),pp,E, until further data become available. Here, P(repl),pp,E for five commercially available parallel-plate chambers was measured as a function o...

journal_title：Medical physics

authors： Reft CS,Kuchnir FT

更新日期：1991-11-01 00:00:00

abstract：:A modified neutron production target assembly has been developed to provide improved performance of the proton-cyclotron-based neutron radiotherapy facility at the University of Washington for applications involving neutron capture enhanced fast-neutron therapy. The new target produces a neutron beam that yields essen...

journal_title：Medical physics

authors： Nigg DW,Wemple CA,Risler R,Hartwell JK,Harker YD,Laramore GE

更新日期：2000-02-01 00:00:00

abstract：:Due to practical limitations in data acquisition, 3-D computed tomography systems must attempt to provide rapid reconstructions of acceptable quality from a limited number of views. The use of convolution backprojection (CBP) for image reconstruction from an inadequate number of projections, results in view aliasing a...

journal_title：Medical physics

authors： Galigekere RR,Wiesent K,Holdsworth DW

更新日期：1999-06-01 00:00:00

abstract：:The wall of an ionization chamber is commonly assumed to have a negligible effect on chamber response in electron beams. For cylindrical chambers with thin walls this assumption is valid. However, parallel-plate chambers commonly possess large mechanical supports which may affect chamber response in a manner not accou...

journal_title：Medical physics

authors： Hunt MA,Kutcher GJ,Buffa A

更新日期：1988-01-01 00:00:00

abstract：PURPOSE:The availability of accurate and simple models for the estimation of x-ray spectra is of great importance for system simulation, optimization, or inclusion of photon energy information into data processing. There is a variety of publicly available tools for estimation of x-ray spectra in radiology and mammograp...

journal_title：Medical physics

authors： Sisniega A,Desco M,Vaquero JJ

更新日期：2014-01-01 00:00:00

abstract：PURPOSE:The Small Animal Radiation Research Platform (SARRP) has been developed for conformal microirradiation with on-board cone beam CT (CBCT) guidance. The graphics processing unit (GPU)-accelerated Superposition-Convolution (SC) method for dose computation has been integrated into the treatment planning system (TPS...

journal_title：Medical physics

authors： Cho N,Tsiamas P,Velarde E,Tryggestad E,Jacques R,Berbeco R,McNutt T,Kazanzides P,Wong J

更新日期：2018-05-01 00:00:00

abstract：:We are developing computerized methods for characterizing the bone texture pattern from digitized skeletal radiographs. For this method to be useful clinically, it must be able to distinguish between weak and strong bone under the range of exposure conditions potentially encountered in the clinical setting. In this st...

journal_title：Medical physics

authors： Chinander MR,Giger ML,Martell JM,Favus MJ

更新日期：2000-01-01 00:00:00

abstract：:A test device which can indirectly measure the performance of an automatic exposure control system and which offers the potential to reduce the time and film requirements for such tests has been evaluated. Evaluation results demonstrate that the device can successfully predict image optical density to within +/- 0.10 ...

journal_title：Medical physics

authors： Rossi RP

更新日期：1994-01-01 00:00:00

abstract：:A nondestructive and noninvasive method for numeric characterization (quantification) of the structural composition of human bone tissue has been developed and tested. In order to quantify and to compare the structural composition of bones from 2D computed tomography (CT) images acquired at different skeletal location...

journal_title：Medical physics

authors： Saparin P,Thomsen JS,Kurths J,Beller G,Gowin W

更新日期：2006-10-01 00:00:00

abstract：:An electronic scanning-slit technology is under development which involves replacing paired fore and aft slits for scatter rejection with only one fore slit. As the slit scans across the portion of the patient to be imaged, pulsed x-ray exposures produce images of the slit in successive positions, which are digitized ...

journal_title：Medical physics

authors： Plenkovich D,Sorenson JA,Kruger RA

更新日期：1986-03-01 00:00:00

abstract：PURPOSE:Color images are visualized on medical monitors that are adjusted by a grayscale standard display function (GSDF) or γ2.2. Although the GSDF is visually displayed as a linear graded grayscale, it does not specify how color medical images should be presented. On the other hand, the usual gamma setting for color ...

journal_title：Medical physics

authors： Shibutani T,Onoguchi M,Yoneyama H,Nakajima K,Matsuo S,Bamba Y,Saito S

更新日期：2019-06-01 00:00:00

abstract：PURPOSE:High-spatial-resolution x-ray imaging in the few-ten-keV range is becoming increasingly important in several applications, such as small-animal imaging and phase-contrast imaging. The detector properties critically influence the quality of such imaging. Here the authors present a quantitative comparison of scin...

journal_title：Medical physics

authors： Larsson JC,Lundström U,Hertz HM

更新日期：2016-06-01 00:00:00

abstract：:The authors are investigating the concept of a direct-conversion flat-panel imager with avalanche gain for low-dose x-ray imaging. It consists of an amorphous selenium (a-Se) photoconductor partitioned into a thick drift region for x-ray-to-charge conversion and a relatively thin region called high-gain avalanche rush...

journal_title：Medical physics

authors： Wronski MM,Rowlands JA

更新日期：2008-12-01 00:00:00

abstract：PURPOSE:The extensive use of computed tomography (CT) in diagnostic procedures is accompanied by a growing need for more accurate and patient-specific dosimetry techniques. Optically stimulated luminescent dosimeters (OSLDs) offer a potential solution for patient-specific CT point-based surface dosimetry by measuring a...

journal_title：Medical physics

authors： Scarboro SB,Cody D,Alvarez P,Followill D,Court L,Stingo FC,Zhang D,McNitt-Gray M,Kry SF

更新日期：2015-04-01 00:00:00

abstract：:The purpose of this study is to incorporate the dosimetric effect of random patient positioning uncertainties directly into a commercial treatment planning system's IMRT plan optimization algorithm through probabilistic treatment planning (PTP) and compare coverage of this method with margin-based planning. In this wo...

journal_title：Medical physics

authors： Moore JA,Gordon JJ,Anscher MS,Siebers JV

更新日期：2009-09-01 00:00:00

abstract：PURPOSE:Having been overlooked for many years, research is now starting to take into account the directional distribution of neutron workplace fields. Existing neutron dosimetry instrumentation does not account for this directional distribution, resulting in conservative estimates of dose in neutron workplace fields (b...

journal_title：Medical physics

authors： Balmer MJ,Gamage KA,Taylor GC

更新日期：2016-11-01 00:00:00

abstract：PURPOSE:Automated 3D breast ultrasound (ABUS) has gained interest in breast imaging. Especially for screening women with dense breasts, ABUS appears to be beneficial. However, since the amount of data generated is large, the risk of oversight errors is substantial. Computer aided detection (CADe) may be used as a secon...

journal_title：Medical physics

authors： Tan T,Mordang JJ,van Zelst J,Grivegnée A,Gubern-Mérida A,Melendez J,Mann RM,Zhang W,Platel B,Karssemeijer N

更新日期：2015-04-01 00:00:00

abstract：PURPOSE:Identification of calcifications and hemorrhages is essential for the etiological diagnosis of cerebral lesions. The purpose of this work was to develop a robust method for characterization of para- and diamagnetic intracerebral lesions based on clinical gradient-echo magnetic resonance phase data acquired at 1...

journal_title：Medical physics

authors： Schweser F,Deistung A,Lehr BW,Reichenbach JR

更新日期：2010-10-01 00:00:00

abstract：:A general expression is derived for the NMR signal from a fluid undergoing random directional flow such as encountered within the microcirculation. The dependence of the echo amplitude on flow velocity, sample morphology, and experimental parameters are described in terms of a temporal velocity autocorrelation functio...

journal_title：Medical physics

authors： Kennan RP,Gao JH,Zhong J,Gore JC

更新日期：1994-04-01 00:00:00

abstract：PURPOSE:To formulate convex planning objectives of treatment plan multicriteria optimization with explicit relationships to the dose-volume histogram (DVH) statistics used in plan quality evaluation. METHODS:Conventional planning objectives are designed to minimize the violation of DVH statistics thresholds using pena...

journal_title：Medical physics

authors： Engberg L,Forsgren A,Eriksson K,Hårdemark B

更新日期：2017-06-01 00:00:00

abstract：:The aim of the present study is to examine the validity of using silicon semiconductor detectors in degraded electron beams with a broad energy spectrum and a wide angular distribution. A comparison is made with diamond detector measurements, which is the dosimeter considered to give the best results provided that dos...

journal_title：Medical physics

authors： Björk P,Knöös T,Nilsson P

更新日期：2000-11-01 00:00:00