X-ray-transmission computed tomography.

abstract：:Vessel size measurement is perhaps the most often performed quantitative analysis in diagnostic and interventional angiography. Although automated vessel sizing techniques are generally considered to have good accuracy and precision, we have observed that clinicians rarely use these techniques in standard clinical pra...

journal_title：Medical physics

authors： Hoffmann KR,Dmochowski J,Nazareth DP,Miskolczi L,Nemes B,Gopal A,Wang Z,Rudin S,Bednarek DR

更新日期：2003-04-01 00:00:00

abstract：PURPOSE:To design and quantify the shielding efficacy of an inner Borated Polyethylene (BPE)wall for a 15 MV linac in a low energy vault. METHODS:A Varian TrueBeam linac with a maximum photon energy of 15 MV was installed in asmaller, preexisting vault. This vault originally housed a low-energy machine and did not hav...

journal_title：Medical physics

authors： Speiser M,Hager F,Foster R,Solberg T

更新日期：2012-06-01 00:00:00

abstract：:Intensity modulated radiation therapy (IMRT) is used to deliver highly conformal radiation doses to tumors while sparing nearby sensitive tissues. Discrepancies between calculated and measured dose distributions have been reported for regions of high dose gradients corresponding to complex radiation fluence patterns. ...

journal_title：Medical physics

authors： Bergman AM,Otto K,Duzenli C

更新日期：2004-12-01 00:00:00

abstract：:The image display is an important component of the Picture Archiving and Communication System (PACS) and of digital imaging in general. In this paper, we assess the display performance of 32 different flat panel LCD devices, in terms of their reflection, luminance response, luminance uniformity, resolution, noise, vei...

journal_title：Medical physics

authors： Jung H,Kim HJ,Kang WS,Yoo SK,Fujioka K,Hasegawa M,Samei E

更新日期：2004-07-01 00:00:00

abstract：:Currently, patients with brain neoplasms must undergo both computed tomography (CT) and magnetic resonance (MR) imaging to take advantage of CT's density information and MR's soft tissue imaging capabilities. A method has been developed that allows virtual simulation, digitally reconstructed radiographs (DRRs), and 3-...

journal_title：Medical physics

authors： Ramsey CR,Oliver AL

更新日期：1998-10-01 00:00:00

abstract：PURPOSE:The authors discuss measurement methods and instrumentation useful for the characterization of the gray tracking performance of medical color monitors for diagnostic applications. The authors define gray tracking as the variability in the chromaticity of the gray levels in a color monitor. METHODS:The authors ...

journal_title：Medical physics

authors： Badano A,Wang J,Boynton P,Le Callet P,Cheng WC,Deroo D,Flynn MJ,Matsui T,Penczek J,Revie C,Samei E,Steven PM,Swiderski S,Van Hoey G,Yamaguchi M,Hasegawa M,Nagy BV

更新日期：2016-07-01 00:00:00

abstract：:Intensity modulated radiation therapy (IMRT) with a dynamic multileaf collimator (DMLC) requires synchronization of DMLC leaf motion with dose delivery. A delay in DMLC communication is known to cause leaf lag and lead to dosimetric errors. The errors may be exacerbated by gated operation. The purpose of this study wa...

journal_title：Medical physics

authors： Duan J,Shen S,Fiveash JB,Brezovich IA,Popple RA,Pareek PN

更新日期：2003-08-01 00:00:00

abstract：PURPOSE:Patient-specific IMRT QA measurements are important components of processes designed to identify discrepancies between calculated and delivered radiation doses. Discrepancy tolerance limits are neither well defined nor consistently applied across centers. The AAPM TG-218 report provides a comprehensive review a...

journal_title：Medical physics

authors： Miften M,Olch A,Mihailidis D,Moran J,Pawlicki T,Molineu A,Li H,Wijesooriya K,Shi J,Xia P,Papanikolaou N,Low DA

更新日期：2018-04-01 00:00:00

abstract：PURPOSE:To examine schemes to grade the severity of metal susceptibility artifacts on image quality using cardiac MRI pulse sequences. METHODS:A post-thoracotomy patient was simulated with a stainless steel sternal wire (Syneture,MA; size=6, diameter=48mm), placed securely on an ACR MRI phantom. Phantom was scanned on...

journal_title：Medical physics

authors： Joyner D,Rivard A,Craft D,Liu T,Callaway S,James J

更新日期：2012-06-01 00:00:00

abstract：:Conventional chest radiography is limited by the presence of scattered radiation and the small useful exposure range of radiographic film. A computer-assisted scanning system to minimize these two effects is outlined. The system uses a small beam of radiation swept over the patient's chest in a raster pattern to expos...

journal_title：Medical physics

authors： Plewes DB

更新日期：1983-09-01 00:00:00

abstract：:Electronic portal imaging devices (EPIDs) are mainly used for patient setup verification during treatment but other geometric properties like block shape and leaf positions are also determined. Electronic portal dosimetry allows dosimetric treatment verification. By combining geometric and dosimetric information, the ...

journal_title：Medical physics

authors： Nijsten SM,Minken AW,Lambin P,Bruinvis IA

更新日期：2004-02-01 00:00:00

abstract：PURPOSE:In 3D gradient echo magnetic resonance imaging (MRI), strong field gradients B0macro are visually observed at air/tissue interfaces. At low spatial resolution in particular, the respective field gradients lead to an apparent increase in intravoxel dephasing, and subsequently, to signal loss or inaccurate R2* es...

journal_title：Medical physics

authors： Fatnassi C,Boucenna R,Zaidi H

更新日期：2017-07-01 00:00:00

abstract：PURPOSE:The purpose of the study is to investigate the characteristics of a two-dimensional (2D) liquid-filled ion chamber detector array, which is used for the verification of radiotherapy treatment plans that use small field sizes of up to 10 × 10 cm. METHODS:The device used in this study was Octavius 1000 SRS model...

journal_title：Medical physics

authors： Markovic M,Stathakis S,Mavroidis P,Jurkovic IA,Papanikolaou N

更新日期：2014-05-01 00:00:00

abstract：PURPOSE:The aim of in vivo skin dosimetry was to measure the absorbed dose to the skin during radiotherapy, when treatment planning calculations cannot be relied on. It is of particularly importance in hypo-fractionated stereotactic modalities, where excessive dose can lead to severe skin toxicity. Currently, commercia...

journal_title：Medical physics

authors： Vicoroski N,Espinoza A,Duncan M,Oborn BM,Carolan M,Metcalfe P,Menichelli D,Perevertaylo VL,Lerch MLF,Rosenfeld AB,Petasecca M

更新日期：2017-10-01 00:00:00

abstract：PURPOSE:Monte Carlo (MC) simulation can be used for accurate electron beam treatment planning and modeling. Measurement of large electron fields, with the applicator removed and secondary collimator wide open, has been shown to provide accurate simulation parameters, including asymmetry in the measured dose, for the fu...

journal_title：Medical physics

authors： O'Shea TP,Foley MJ,Faddegon BA

更新日期：2011-06-01 00:00:00

abstract：PURPOSE:The combination of nonhuman primates (NHPs) with the state-of-the-art molecular imaging technologies allows for within-subject longitudinal research aiming at gaining new insights into human normal and disease conditions and provides an ideal foundation for future translational studies of new diagnostic tools, ...

journal_title：Medical physics

authors： Xie T,Chen X,Zaidi H

更新日期：2020-09-01 00:00:00

abstract：PURPOSE:Removal of the linear accelerator (linac) flattening filter enables a high rate of dose deposition with reduced treatment time. When used for megavoltage imaging, an unflat beam has reduced primary beam scatter resulting in sharper images. In fluoroscopic imaging mode, the unflat beam has higher photon count pe...

journal_title：Medical physics

authors： Christensen JD,Kirichenko A,Gayou O

更新日期：2013-08-01 00:00:00

abstract：:The calibration (in rad/nC) of an air-filled tissue-equivalent ionization chamber for neutrons of 15-MeV average energy was determined by measuring absolute fluences and calculating the kerma per unit fluence. The neutron calibration determined from the gamma-ray calibration and application of the Bragg-Gray relation ...

journal_title：Medical physics

authors： Barschall HH,Goldberg E

更新日期：1977-03-01 00:00:00

abstract：:We have performed a comprehensive dosimetric characterization of the Oncura model 6711 125I seed using both experimental [LiF thermoluminscent dosimetry (TLD)] and theoretical (Monte Carlo photon transport) methods. In addition to determining the dosimetric parameters of the 6711, this report quantified: (1) the angul...

journal_title：Medical physics

authors： Dolan J,Lia Z,Williamson JF

更新日期：2006-12-01 00:00:00

abstract：:Monte Carlo simulations of x-ray beams typically take parameters of the electron beam in the accelerating waveguide to be free parameters. In this paper, a methodology is proposed and implemented to determine the energy, spectral width, and beam divergence of the electron source. All treatment head components were rem...

journal_title：Medical physics

authors： Sawkey DL,Faddegon BA

更新日期：2009-03-01 00:00:00

abstract：:A theoretical analysis of the x-ray phase contrast imaging and its validation via synchrotron radiation imaging is here presented. Two different mathematical models have been followed: the simpler ray-optical approach and the more rigorous Fresnel-Kirchoff diffraction theory. Subsequently, the conditions upon which th...

journal_title：Medical physics

authors： Peterzol A,Olivo A,Rigon L,Pani S,Dreossi D

更新日期：2005-12-01 00:00:00

abstract：PURPOSE:To present the results of a patient dose evaluation program in pediatric cardiology and propose local diagnostic reference levels (DRLs) for different types of procedure and age range, in addition to suggesting approaches to correlate patient dose values with patient weight. This study was the first conducted i...

journal_title：Medical physics

authors： Ubeda C,Miranda P,Vano E

更新日期：2015-02-01 00:00:00

abstract：PURPOSE:The purpose of this study is to investigate whether the microvascular pseudodiffusion effects resulting with non-monoexponential behavior are present in breast cancer, taking into account tumor spatial heterogeneity. Additionally, methodological factors affecting the signal in low and high diffusion-sensitizing...

journal_title：Medical physics

authors： Panek R,Borri M,Orton M,O'Flynn E,Morgan V,Giles SL,deSouza N,Leach MO,Schmidt MA

更新日期：2015-08-01 00:00:00

abstract：:The radiation dose to the lungs from 133Xe in lung air is directly proportional to the time integral of 133Xe concentration; i.e., the cumulated concentration in the lungs. Using kinetic models developed to fit clinical observations, we have studied the effect of retention on cumulated concentration in lung air. The m...

journal_title：Medical physics

authors： Watson EE,Cloutier RJ

更新日期：1977-11-01 00:00:00

abstract：PURPOSE:In this article, the authors propose a new gold standard data set for the validation of two-dimensional/three-dimensional (2D/3D) and 3D/3D image registration algorithms. METHODS:A gold standard data set was produced using a fresh cadaver pig head with attached fiducial markers. The authors used several imagin...

journal_title：Medical physics

authors： Pawiro SA,Markelj P,Pernus F,Gendrin C,Figl M,Weber C,Kainberger F,Nöbauer-Huhmann I,Bergmeister H,Stock M,Georg D,Bergmann H,Birkfellner W

更新日期：2011-03-01 00:00:00

abstract：:Noise characterization through estimation of the noise power spectrum (NPS) is a central component of the evaluation of digital x-ray systems. We begin with a brief review of the fundamentals of NPS theory and measurement, derive explicit expressions for calculation of the one- and two-dimensional (1D and 2D) NPS, and...

journal_title：Medical physics

authors： Williams MB,Mangiafico PA,Simoni PU

更新日期：1999-07-01 00:00:00

abstract：PURPOSE:Although small animal image-guided radiotherapy (SA-IGRT) systems are used increasingly in preclinical research, tools for performing routine quality assurance (QA) have not been optimized and are not readily available. Robust, efficient, and reliable QA tools are needed to ensure the accuracy and reproducibili...

journal_title：Medical physics

authors： Anvari A,Poirier Y,Sawant A

更新日期：2018-07-01 00:00:00

abstract：:Various radionuclides have been proposed for systemic tumor therapy. However, in most dosimetric analysis of proposed radionuclides the charged particles are taken into consideration while the potential photons are ignored. The photons will cause undesirable irradiation of normal tissue, and increase the probability o...

journal_title：Medical physics

authors： Uusijärvi H,Bernhardt P,Ericsson T,Forssell-Aronsson E

更新日期：2006-09-01 00:00:00

abstract：PURPOSE:The purpose of this study was to assess the accuracy of a Monte Carlo simulation-based method for estimating radiation dose from multidetector computed tomography (MDCT) by comparing simulated doses in ten patients to in-vivo dose measurements. METHODS:MD Anderson Cancer Center Institutional Review Board appro...

journal_title：Medical physics

authors： Bostani M,Mueller JW,McMillan K,Cody DD,Cagnon CH,DeMarco JJ,McNitt-Gray MF

更新日期：2015-02-01 00:00:00

abstract：PURPOSE:To implement the DMAIC (Define-Measure-Analyze-Improve-Control) can be used for customizing the patient-specific QA by designing site-specific range tolerances. METHODS:The DMAIC framework (process flow diagram, cause and effect, Pareto chart, control chart, and capability analysis) were utilized to determine ...

journal_title：Medical physics

authors： Rah JE,Shin D,Manger RP,Kim TH,Oh DH,Kim DY,Kim GY

更新日期：2018-02-01 00:00:00