Penetration quality measurement for standardization of radiographic image quality.

abstract：PURPOSE:Different approaches have been used in dynamic elastography to assess mechanical properties of biological tissues. Most techniques are based on a simple inversion based on the measurement of the shear wave speed to assess elasticity, whereas some recent strategies use more elaborated analytical or finite elemen...

journal_title：Medical physics

authors： Ouared A,Kazemirad S,Montagnon E,Cloutier G

更新日期：2016-04-01 00:00:00

abstract：PURPOSE:The aim of this study was to assess the suitability of Gafchromic EBT3 films for reference dose measurements in the beam of a prototype high dose-per-pulse linear accelerator (linac), capable of delivering electron beams with a mean dose-rate (Ḋm ) ranging from 0.07 to 3000 Gy/s and a dose-rate in pulse (Ḋp ) o...

journal_title：Medical physics

authors： Jaccard M,Petersson K,Buchillier T,Germond JF,Durán MT,Vozenin MC,Bourhis J,Bochud FO,Bailat C

更新日期：2017-02-01 00:00:00

abstract：PURPOSE:To develop a hypothesis-generating framework for automatic extraction of dose-outcome relationships from an in-house, analytic oncology database. METHODS:Dose-volume histograms (DVH) and clinical outcomes have been routinely stored to the authors' database for 684 head and neck cancer patients treated from 200...

journal_title：Medical physics

authors： Robertson SP,Quon H,Kiess AP,Moore JA,Yang W,Cheng Z,Afonso S,Allen M,Richardson M,Choflet A,Sharabi A,McNutt TR

更新日期：2015-07-01 00:00:00

abstract：:A spread-out Bragg peak (SOBP) is used in proton beam therapy to create a longitudinal conformality of the required dose to the target. In order to create this effect in a passive beam scattering system, a variety of components must operate in conjunction to produce the desired beam parameters. We will describe how th...

journal_title：Medical physics

authors： Lu HM,Brett R,Engelsman M,Slopsema R,Kooy H,Flanz J

更新日期：2007-10-01 00:00:00

abstract：PURPOSE:To develop a pencil beam dose calculation algorithm for scanned proton beams that improves modeling of scatter events. METHODS:Our pencil beam algorithm (PBA) was developed for calculating dose from monoenergetic, parallel proton beams in homogeneous media. Fermi-Eyges theory was implemented for pencil beam tr...

journal_title：Medical physics

authors： Chapman J,Fontenot J,Newhauser W,Hogstrom K

更新日期：2012-06-01 00:00:00

abstract：:Complementary metal-oxide-semiconductors (CMOS) active pixel sensors can be optically coupled to CsI:Tl phosphors forming a indirect active pixel flat panel imager (APFPI) for high performance medical imaging. The aim of this work is to determine the x-ray imaging capabilities of CMOS-based APFPI and study the signal ...

journal_title：Medical physics

authors： Arvanitis CD,Bohndiek SE,Blakesley J,Olivo A,Speller RD

更新日期：2009-01-01 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：:A system for measuring two-dimensional (2D) dose distributions in orthogonal anatomical planes in the cranium was developed and used to evaluate the accuracy of coplanar conformal therapy using ExacTrac image guidance. Dose distributions were measured in the axial, sagittal, and coronal planes using a CIRS (Computeriz...

journal_title：Medical physics

authors： Vinci JP,Hogstrom KR,Neck DW

更新日期：2008-08-01 00:00:00

abstract：:Projected light fields are used on treatment simulators and teletherapy treatment units to delineate the size and position of the radiation beam. Any discrepancy between these fields will lead to a systematic field placement error, with possibly serious implications with regard to the accuracy of the delivered dose di...

journal_title：Medical physics

authors： Luchka K,Chen D,Shalev S,Gluhchev G,Rajapakshe R

更新日期：1996-07-01 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 this work is twofold: First, to characterize the artifacts occurring in helical 4D-CT imaging; second, to propose a method that can automatically identify the artifacts in 4D-CT images. The authors have designed a process that can automatically identify the artifacts in 4D-CT images, which may be...

journal_title：Medical physics

authors： Han D,Bayouth J,Bhatia S,Sonka M,Wu X

更新日期：2011-04-01 00:00:00

abstract：:Current generation electronic portal imaging devices (EPID) contain a 1.0 mm copper conversion plate to increase detection efficiency of a therapeutic megavoltage spectrum. When using these EPIDs for low-Z target imaging, the conversion plate largely attenuates the large populations of diagnostic energy photons, there...

journal_title：Medical physics

authors： Parsons D,Robar JL

更新日期：2012-07-01 00:00:00

abstract：:Two new liquid ionization chamber (LIC) designs, consisting of cylindrical and plane-parallel configurations, are presented. They are designed to be suitable for high-precision measurements of absorbed dose-to-water at dose rates and photon energies typical for LDR intermediate photon energy brachytherapy sources. The...

journal_title：Medical physics

authors： Wickman G,Johansson B,Bahar-Gogani J,Holmström T,Grindborg JE

更新日期：1998-06-01 00:00:00

abstract：PURPOSE:To improve image quality and reduce imaging dose in CBCT for radiation therapy applications and to realize near real-time image reconstruction based on use of a fast convergence iterative algorithm and acceleration by multi-GPUs. METHODS:An iterative image reconstruction that sought to minimize a weighted leas...

journal_title：Medical physics

authors： Xu Q,Yang D,Tan J,Anastasio M

更新日期：2012-06-01 00:00:00

abstract：:Molecular imaging is the direct or indirect noninvasive monitoring and recording of the spatial and temporal distribution of in vivo molecular, genetic, and/or cellular processes for biochemical, biological, diagnostic, or therapeutic applications. Molecular images that indicate the presence of malignancy can be acqui...

journal_title：Medical physics

authors： Munley MT,Kagadis GC,McGee KP,Kirov AS,Jang S,Mutic S,Jeraj R,Xing L,Bourland JD

更新日期：2013-10-01 00:00:00

abstract：PURPOSE:Real-time adaptive planning and treatment has been infeasible due in part to its high computational complexity. There have been many recent efforts to utilize graphics processing units (GPUs) to accelerate the computational performance and dose accuracy in radiation therapy. Data structure and memory access pat...

journal_title：Medical physics

authors： Neylon J,Sheng K,Yu V,Chen Q,Low DA,Kupelian P,Santhanam A

更新日期：2014-10-01 00:00:00

abstract：PURPOSE:The National Council for Radiation Protection and Measurement (NCRP) published estimates for the collective population dose and the mean effective dose to the population of the United States from medical imaging procedures for 1980/1982 and for 2006. The earlier report ignored the effective dose from radiothera...

journal_title：Medical physics

authors： Uselmann AJ,Thomadsen BR

更新日期：2015-02-01 00:00:00

abstract：PURPOSE:We present a simple, practical framework for truly 4D lung IMRT planning based on a weighted individual-phase optimization paradigm. This strategy is specifically developed for use in real-time tumor tracking delivery systems so as to utilize respiratory motion as an additional degree of freedom rather than a c...

journal_title：Medical physics

authors： Tachibana H,Cheung Y,Jain S,Sawant A

更新日期：2012-06-01 00:00:00

abstract：:Machine outputs, peak scatter factors, and central axis percentage depth dose distributions were measured for various phantom sizes in large radiation fields produced at extended distances by cobalt, 6-MV, and 10-MV photon beams. The results can be applied to practical total body irradiation procedures which usually i...

journal_title：Medical physics

authors： Podgorsak EB,Pla C,Evans MD,Pla M

更新日期：1985-09-01 00:00:00

abstract：PURPOSE:Currently applied calibration approaches lead to satisfying 3D roadmapping overlay and 3D reconstruction accuracies; however, the required calibration times are extensive. The aim of this paper is the introduction of a novel model-based approach for geometric system calibrations, leading to a significant reduct...

journal_title：Medical physics

authors： van der Maas R,de Jager B,Steinbuch M,Dries J

更新日期：2015-11-01 00:00:00

abstract：:Bioluminescent imaging (BLI) of luciferase-expressing cells in live small animals is a powerful technique for investigating tumor growth, metastasis, and specific biological molecular events. Three-dimensional imaging would greatly enhance applications in biomedicine since light emitting cell populations could be unam...

journal_title：Medical physics

authors： Slavine NV,Lewis MA,Richer E,Antich PP

更新日期：2006-01-01 00:00:00

abstract：PURPOSE:To investigate how using different sets of decision criteria impacts the quality of intensity modulated radiation therapy (IMRT) plans obtained by multiobjective optimization. METHODS:A multiobjective optimization evolutionary algorithm (MOEA) was used to produce sets of IMRT plans. The MOEA consisted of two i...

journal_title：Medical physics

authors： Holdsworth C,Stewart RD,Kim M,Liao J,Phillips MH

更新日期：2011-06-01 00:00:00

abstract：PURPOSE:Quantitative cone-beam CT (CBCT) imaging is on increasing demand for high-performance image guided radiation therapy (IGRT). However, the current CBCT has poor image qualities mainly due to scatter contamination. Its current clinical application is therefore limited to patient setup based on only bony structure...

journal_title：Medical physics

authors： Niu T,Al-Basheer A,Zhu L

更新日期：2012-04-01 00:00:00

abstract：:Although x-ray computed tomography (CT) has been in clinical use for over 3 decades, spectral optimization has not been a topic of great concern; high voltages around 120 kV have been in use since the beginning of CT. It is the purpose of this study to analyze, in a rigorous manner, the energies at which the patient d...

journal_title：Medical physics

authors： Kalender WA,Deak P,Kellermeier M,van Straten M,Vollmar SV

更新日期：2009-03-01 00:00:00

abstract：:Dose calculations for treatment planning of photon beam radiotherapy require a model of the beam to drive the dose calculation models. The beam shaping process involves scattering and filtering that yield radiation components which vary with collimator settings. The necessity to model these components has motivated th...

journal_title：Medical physics

authors： Ahnesjö A,Weber L,Murman A,Saxner M,Thorslund I,Traneus E

更新日期：2005-06-01 00:00:00

abstract：PURPOSE:We studied the sensitivity of a novel transmission fiber scintillator array designed and built for in line treatment verification. The purpose of this project is to assess the capability of the fiber detector array technology to detect treatment errors in real time without false positives to enhance patient saf...

journal_title：Medical physics

authors： Izaguirre EW,Price SG,Smajlovic S,Yaddanapudi S,Wooten H,Mutic S

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:To develop a real-time markerless 3D tumor tracking using kilovoltage (kV) cone-beam CT (CBCT) projection images during volumetric modulated arc therapy (VMAT) treatment of lung tumors. METHODS:The authors have developed a method to identify the position of lung tumors during VMAT treatment, where the current ...

journal_title：Medical physics

authors： Zhuang L,Liang J,Yan D,Zhang T,Marina O,Ionascu D

更新日期：2013-10-01 00:00:00

abstract：PURPOSE:In this study the Octavius detector 729 ionization chamber (IC) array with the Octavius 4D phantom was characterized for flattening filter (FF) and flattening filter free (FFF) static and rotational beams. The device was assessed for verification with FF and FFF RapidArc treatment plans. METHODS:The response o...

journal_title：Medical physics

authors： McGarry CK,O'Connell BF,Grattan MW,Agnew CE,Irvine DM,Hounsell AR

更新日期：2013-09-01 00:00:00

abstract：PURPOSE:Severe artifacts in kilovoltage-CT simulation images caused by large metallic implants can significantly degrade the conspicuity and apparent CT Hounsfield number of targets and anatomic structures, jeopardize the confidence of anatomical segmentation, and introduce inaccuracies into the radiation therapy treat...

journal_title：Medical physics

authors： Li H,Noel C,Chen H,Harold Li H,Low D,Moore K,Klahr P,Michalski J,Gay HA,Thorstad W,Mutic S

更新日期：2012-12-01 00:00:00

abstract：PURPOSE:The variable resolution x-ray (VRX) CT scanner provides substantial improvement in the spatial resolution by matching the scanner's field of view (FOV) to the size of the object being imaged. Intercell x-ray cross-talk is one of the most important factors limiting the spatial resolution of the VRX detector. In ...

journal_title：Medical physics

authors： Arabi H,Asl AR,Ay MR,Zaidi H

更新日期：2011-03-01 00:00:00