Robust experiment design for estimating myocardial beta adrenergic receptor concentration using PET.

abstract：PURPOSE:We have developed a robust tool for performing volumetric and temporal analysis of nodules from respiratory gated four-dimensional (4D) CT. The method could prove useful in IMRT of lung cancer. METHODS:We modified the conventional graph-cuts method by adding an adaptive shape prior as well as motion informatio...

journal_title：Medical physics

authors： Cha J,Farhangi MM,Dunlap N,Amini AA

更新日期：2018-01-01 00:00:00

abstract：PURPOSE:The need for four-dimensional (4D) treatment planning becomes indispensable when it comes to radiation therapy for moving tumors in the thoracic and abdominal regions. The primary purpose of this study is to combine the actual breathing trace during each individual treatment fraction with the Linac's log file i...

journal_title：Medical physics

authors： Freislederer P,von Münchow A,Kamp F,Heinz C,Gerum S,Corradini S,Söhn M,Reiner M,Roeder F,Floca R,Alber M,Belka C,Parodi K

更新日期：2019-07-01 00:00:00

abstract：:An easy-to-use phantom has been constructed for checking the accuracy of a stereotactic computed tomography localization system. This phantom has been used on a commercially available stereotactic radiosurgery system. With this system, the phantom reference point, whose location is established by means of a precision ...

journal_title：Medical physics

authors： Ekstrand KE,Olds WW,Branch CL

更新日期：1993-03-01 00:00:00

abstract：:For diagnostic ultrasound imaging, as in computed tomography, a feature of prime importance is the detection of focal lesions of varying size and contrast (echo amplitude) from surrounding tissue. This study describes a new tissue-stimulating phantom which has been used to measure the threshold detection of varying co...

journal_title：Medical physics

authors： Smith SW,Lopez H

更新日期：1982-01-01 00:00:00

abstract：:Compared with slice-by-slice approaches for SPECT reconstruction, three-dimensional iterative methods provide a more accurate physical model and an improved SPECT image. Clinical application of these methods, however, is limited primarily to their computational demands. This paper investigates the methods for approxim...

journal_title：Medical physics

authors： Gilland DR,Jaszczak RJ,Riauka TA,Coleman RE

更新日期：1997-09-01 00:00:00

abstract：:The use of electronic portal imaging devices (EPIDs) is a promising method for the dosimetric verification of external beam, megavoltage radiation therapy-both pretreatment and in vivo. In this study, a previously developed EPID back-projection algorithm was modified for IMRT techniques and applied to an amorphous sil...

journal_title：Medical physics

authors： Wendling M,Louwe RJ,McDermott LN,Sonke JJ,van Herk M,Mijnheer BJ

更新日期：2006-02-01 00:00:00

abstract：:Previous ultrasound tomography work conducted by our group showed a direct correlation between measured sound speed and physical density in vitro, and increased in vivo sound speed with increasing mammographic density, a known risk factor for breast cancer. Building on these empirical results, the purpose of this work...

journal_title：Medical physics

authors： Glide-Hurst CK,Duric N,Littrup P

更新日期：2008-09-01 00:00:00

abstract：PURPOSE:An improved method of image guidance for lung tumor biopsies could help reduce the high rate of false negatives. The aim of this work is to optimize the geometry of the scanning-beam digital tomography system (SBDX) for providing real-time 3D tomographic reconstructions for target verification. The unique geome...

journal_title：Medical physics

authors： Nelson G,Yoon S,Krishna G,Wilfley B,Fahrig R

更新日期：2013-11-01 00:00:00

abstract：:In this study, BrachyDose, a recently developed EGSnrc Monte Carlo code for rapid brachytherapy dose calculations, has been benchmarked by reproducing previously published dosimetry parameters for three brachytherapy seeds with varied internal structure and encapsulation. Calculations are performed for two 125I seeds ...

journal_title：Medical physics

authors： Taylor RE,Yegin G,Rogers DW

更新日期：2007-02-01 00:00:00

abstract：PURPOSE:The efficiency of radioembolization procedures could be greatly enhanced if results of the 99m Tc-MAA pretreatment procedure were immediately available in the interventional suite, enabling 1-day procedures as a result of direct estimation of the hepatic radiation dose and lung shunt fraction. This would, howev...

journal_title：Medical physics

authors： van der Velden S,Dietze MMA,Viergever MA,de Jong HWAM

更新日期：2019-01-01 00:00:00

abstract：PURPOSE:To apply the recent code of practice from the IAEA/AAPM, TRS 483, to helical tomotherapy (HT) for reference and relative dosimetry obtaining correction factors for the Exradin A1SL ionization chamber. METHODS:The beam quality correction factor for the A1SL chamber was obtained through three different approache...

journal_title：Medical physics

authors： Lopes MDC,Santos T,Ventura T,Capela M

更新日期：2019-12-01 00:00:00

abstract：:Measurements of a 670-MeV/amu 20Ne beam at the Lawrence Berkeley Laboratory Bevalac heavy-ion accelerator with various thicknesses of water absorber were obtained with the BERKLET. The BERKLET, a simple three-stage solid-state telescope detector, has been described previously. This instrument measures the linear energ...

journal_title：Medical physics

authors： Llacer J,Schmidt JB,Tobias CA

更新日期：1990-03-01 00:00:00

abstract：:A method is proposed for realistic simulation of the breast ductal network as part of a computer three-dimensional (3-D) breast phantom. The ductal network is simulated using tree models. Synthetic trees are generated based upon a description of ductal branching by ramification matrices (R matrices), whose elements re...

journal_title：Medical physics

authors： Bakic PR,Albert M,Brzakovic D,Maidment AD

更新日期：2003-07-01 00:00:00

abstract：PURPOSE:To demonstrate the feasibility of compressed sensing (CS) to accelerate the acquisition of hyperpolarized (HP) 129 Xe multi-b diffusion MRI for quantitative assessments of lung microstructural morphometry. METHODS:Six healthy subjects and six chronic obstructive pulmonary disease (COPD) subjects underwent HP 1...

journal_title：Medical physics

authors： Zhang H,Xie J,Xiao S,Zhao X,Zhang M,Shi L,Wang K,Wu G,Sun X,Ye C,Zhou X

更新日期：2018-07-01 00:00:00

abstract：PURPOSE:To evaluate the dose distribution of a 120-MeV laser-plasma accelerated electron beam which may be of potential interest for high-energy electron radiation therapy. METHODS:In the interaction between an intense laser pulse and a helium gas jet, a well collimated electron beam with very high energy is produced....

journal_title：Medical physics

authors： Lundh O,Rechatin C,Faure J,Ben-Ismaïl A,Lim J,De Wagter C,De Neve W,Malka V

更新日期：2012-06-01 00:00:00

abstract：:Calibration of an imported strontium-90 ophthalmic applicator at the U.S. National Bureau of Standards (now the National Institute of Standards and Technology) has disclose a significant discrepancy in dose rate calibration (32%-35%) with that quoted by the manufacturer. The University of Wisconsin has investigated th...

journal_title：Medical physics

authors： Goetsch SJ,Sunderland KS

更新日期：1991-03-01 00:00:00

abstract：PURPOSE:To develop an automatic knot placement algorithm to enable the use of NonUniform Rational B-Splines (NURBS) in deformable image registration. METHODS:The authors developed a two-step approach to fit a known displacement vector field (DVF). An initial fit was made with uniform knot spacing. The error generated ...

journal_title：Medical physics

authors： Jacobson TJ,Murphy MJ

更新日期：2011-08-01 00:00:00

abstract：:Scanning film densitometry routinely used for obtaining dosimetric information about therapy treatment beams is subject to several sources of inaccuracies. The most significant of these are described and appropriate methods of testing are presented. This establishes the need for adequate acceptance testing followed by...

journal_title：Medical physics

authors： Holmes TW,McCullough EC

更新日期：1983-09-01 00:00:00

abstract：PURPOSE:Secondary particles produced in the collision of protons with beam modifiers are of concern in proton therapy. Nevertheless, secondary radiation can provide information on the dosimetric parameters through its dependency on the modulating accessories (range shifter and range modulating wheel). Relatively little...

journal_title：Medical physics

authors： Carnicer A,Letellier V,Rucka G,Angellier G,Sauerwein W,Herault J

更新日期：2012-12-01 00:00:00

abstract：PURPOSE:To investigate the critical structure sparing achievable by biological optimization for modulated volumetric arc (VMAT) of head and neck (H&N) cancer. METHODS:Ten H&N VMAT patients who were originally planned and treated with simultaneous integrated boost technique using dose-volume based optimization, were se...

journal_title：Medical physics

authors： Dogan N,Wu Y

更新日期：2012-06-01 00:00:00

abstract：:A clamp-on current probe utilizing the Hall effect was used to determine x-ray tube current. This noninvasive technique was compared to two other methods of mA measurement: the Machlett Dynalyzer and the mR/mAs linearity method. Three diagnostic x-ray units were used in the comparison; two modern three-phase rooms and...

journal_title：Medical physics

authors： Atherton JV,Nickoloff EL

更新日期：1987-03-01 00:00:00

abstract：:Ultrasound has been the greatest imaging modality worldwide for many years by equipment purchase value and by number of machines and examinations. It is becoming increasingly the front end imaging modality; serving often as an extension of the physician's fingers. We believe that at the other extreme, high-end systems...

journal_title：Medical physics

authors： Carson PL,Fenster A

更新日期：2009-02-01 00:00:00

abstract：:Proton beams offer several advantages over conventional radiation techniques for treating cancer and other diseases. These advantages might be negated if the leakage and scatter radiation from the beamline and patient are too large. Although the leakage and scatter radiation for the double scattering proton beamlines ...

journal_title：Medical physics

authors： Moyers MF,Benton ER,Ghebremedhin A,Coutrakon G

更新日期：2008-01-01 00:00:00

abstract：PURPOSE:The authors are developing a system for calibrated breast density measurements using full field digital mammography (FFDM). Breast tissue equivalent (BTE) phantom images are used to establish baseline (BL) calibration curves at time zero. For a given FFDM unit, the full BL dataset is comprised of approximately ...

journal_title：Medical physics

authors： Lu B,Smallwood AM,Sellers TA,Drukteinis JS,Heine JJ,Fowler EE

更新日期：2015-02-01 00:00:00

abstract：PURPOSE:High-Z material in computed tomography (CT) yields metal artifacts that degrade image quality and may cause substantial errors in dose calculation. This study couples a metal artifact reduction (MAR) algorithm with enhanced 16-bit depth (vs standard 12-bit) to quantify potential gains in image quality and dosim...

journal_title：Medical physics

authors： Glide-Hurst C,Chen D,Zhong H,Chetty IJ

更新日期：2013-06-01 00:00:00

abstract：:The main purpose of this work is to demonstrate a practical means of determining the leaf transmission and scatter characteristics of a multileaf collimator (MLC) pertinent to the commissioning of dynamic intensity modulated radiotherapy, especially for the sweeping window technique. The data are necessary for the con...

journal_title：Medical physics

authors： Arnfield MR,Siebers JV,Kim JO,Wu Q,Keall PJ,Mohan R

更新日期：2000-10-01 00:00:00

abstract：:The dosimetric characteristics of a new dedicated radiosurgical treatment unit are systematically measured in terms of its percent depth dose, beam profile, and relative scatter factor. High-resolution diode detector, mini-ion-chamber detector, and conventional Kodak XV films are used to measure dosimetric data for a ...

journal_title：Medical physics

authors： Yin FF,Zhu J,Yan H,Gaun H,Hammoud R,Ryu S,Kim JH

更新日期：2002-08-01 00:00:00

abstract：:Effectiveness of an oral presentation depends on the ability of the speaker to communicate with the audience. An important part of this communication is focusing on two to five key points and emphasizing those points during the presentation. Every aspect of the presentation should be purposeful and directed at facilit...

journal_title：Medical physics

authors： Collins J,Aydogan B

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:To evaluate both the Calypso Systems' (Calypso Medical Technologies, Inc., Seattle, WA) localization accuracy in the presence of wireless metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters of dose verification system (DVS, Sicel Technologies, Inc., Morrisville, NC) and the dosimeters' reading...

journal_title：Medical physics

authors： Su Z,Zhang L,Ramakrishnan V,Hagan M,Anscher M

更新日期：2011-05-01 00:00:00

abstract：:With the increasing complexity of dose patterns external beam radiotherapy, there is a great need for new types of dosimeters. We studied the first prototype of a new dosimeter array consisting of water-equivalent plastic scintillating fibers for dose measurement in external beam radiotherapy. We found that this array...

journal_title：Medical physics

authors： Archambault L,Beddar AS,Gingras L,Lacroix F,Roy R,Beaulieu L

更新日期：2007-05-01 00:00:00