4D rotational x-ray imaging of wrist joint dynamic motion.

abstract：PURPOSE:The Synchrony respiratory motion tracking of the CyberKnife system purports to provide real-time tumor motion compensation during robotic radiosurgery. Such a complex delivery system requires thorough quality assurance. In this work, RADPOS applicability as a dose and position quality assurance tool for CyberKn...

journal_title：Medical physics

authors： Marants R,Vandervoort E,Cygler JE

更新日期：2018-07-25 00:00:00

abstract：:Coherent scattering of x-ray photons leads to the phenomenon of x-ray diffraction, which is widely used for determining atomic structure in materials science. A technique [x-ray diffraction computed tomography (CT)] is described, analogous to conventional CT, in which the x-ray diffraction properties of a stack of two...

journal_title：Medical physics

authors： Harding G,Kosanetzky J,Neitzel U

更新日期：1987-07-01 00:00:00

abstract：PURPOSE:To study and compare the dose response curves of the new GafChromic EBT3 film for megavoltage and kilovoltage x-ray beams, with different spatial resolution. METHODS:Two sets of EBT3 films (lot#A101711-02) were exposed to each x-ray beam (6MV, 15MV and 50kV) at 8 dose values (50-3200cGy). The megavoltage beams...

journal_title：Medical physics

authors： Chiu-Tsao S,Massillon-Jl G,Domingo-Muñoz I,Chan M

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:CT reconstruction algorithms implemented on the GPU are highly sensitive to their implementation details and the hardware they run on. Fine-tuning an implementation for optimal performance can be a time consuming task and require many updates when the hardware changes. There are some techniques that do automati...

journal_title：Medical physics

authors： Papenhausen E,Zheng Z,Mueller K

更新日期：2013-03-01 00:00:00

abstract：:Myocardial beta adrenergic receptor (beta-AR) concentration can substantially decrease in congestive heart failure and significantly increase in chronic volume overload, such as in severe aortic valve regurgitation. Positron emission tomography (PET) with an appropriate ligand-receptor model can be used for noninvasiv...

journal_title：Medical physics

authors： Salinas C,Muzic RF Jr,Ernsberger P,Saidel GM

更新日期：2007-01-01 00:00:00

abstract：:Clinical and biological evidence suggest that the success of GRID therapy in debulking large tumors depends on the high peak-to-valley contrast in the dose distribution. In this study, we show that the peaks and valleys can be significantly blurred out by respiration-induced tumor motion, possibly affecting the clinic...

journal_title：Medical physics

authors： Naqvi SA,Mohiuddin MM,Ha JK,Regine WF

更新日期：2008-10-01 00:00:00

abstract：:We are evaluating the usefulness of stereomammography in improving breast cancer diagnosis. One area that we are investigating is whether the improved depth perception associated with stereomammography might be significantly enhanced with the use of a virtual 3D cursor. A study was performed to evaluate the accuracy o...

journal_title：Medical physics

authors： Goodsitt MM,Chan HP,Hadjiiski L

更新日期：2000-06-01 00:00:00

abstract：PURPOSE:The authors have previously reported the advantages of high-sensitivity single-photon emission computed tomography (SPECT) systems for imaging structures located deep inside the brain. DaTscan (Isoflupane I-123) is a dopamine transporter (DaT) imaging agent that has shown potential for early detection of Parkin...

journal_title：Medical physics

authors： Park MA,Moore SC,Müller SP,McQuaid SJ,Kijewski MF

更新日期：2013-04-01 00:00:00

abstract：:A prototype Emission-Transmission Computed Tomography (ETCT) system is being developed that will acquire single-slice x-ray transmission CT images simultaneously with single photon emission computed tomography (SPECT) images. This system will permit the correlation of anatomical information from x-ray CT with function...

journal_title：Medical physics

authors： Liew SC,Hasegawa BH

更新日期：1991-09-01 00:00:00

abstract：:This paper outlines a method for determining proper removal-diffusion parameters to be used in removal-diffusion theory calculations for the purpose of BNCT treatment planning. Additionally, this paper demonstrates that, given the proper choice of removal-diffusion parameters, removal-diffusion theory may provide an a...

journal_title：Medical physics

authors： Albertson BJ,Blue TE,Niemkiewicz J

更新日期：2001-09-01 00:00:00

abstract：:The most favorable treatment for moving body anatomy should aim at utilizing organ motion to minimize the dose to sensitive structures without compromising the dose delivered to the target. The solution of the problem of appropriate intensity redistribution over different phases of body motion is achievable in dynamic...

journal_title：Medical physics

authors： Papiez L,McMahon R,Timmerman R

更新日期：2007-12-01 00:00:00

abstract：PURPOSE:Examine the use of TomoDose for Tomotherapy quality assurance. METHODS:Baseline TomoDose profiles are acquired annually in accordance with TG-148. During monthly quality assurance, TomoDose is irradiated with a static beam and referenced to baseline. Differences between superimposed profiles are evaluated mont...

journal_title：Medical physics

authors： Terrell J

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:To design an efficient method for utilizing phase-space source models in the GPU-based Monte Carlo (MC) dose calculation engine gDPM. METHODS:In GPU-based MC algorithms, particles are transported in parallel on different threads. Particles of different types and energies can require significantly different exe...

journal_title：Medical physics

authors： Townson R,Jia X,Zavgorodni S,Jiang S

更新日期：2012-06-01 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：:Positron emission tomography (PET) is increasingly considered as an effective imaging method to support several stages of radiation therapy. The combined usage of functional and morphological imaging in state-of-the-art PET/CT scanners is rapidly emerging to support the treatment planning process in terms of improved ...

journal_title：Medical physics

authors： Parodi K

更新日期：2015-12-01 00:00:00

abstract：:The goal of this study was to develop a technique to distinguish benign and malignant breast lesions in secondarily digitized mammograms. A set of 51 mammograms (two views/patient) containing lesions of known pathology were evaluated using six different morphological descriptors: circularity, mu R/sigma R (where mu R ...

journal_title：Medical physics

authors： Pohlman S,Powell KA,Obuchowski NA,Chilcote WA,Grundfest-Broniatowski S

更新日期：1996-08-01 00:00:00

abstract：PURPOSE:To achieve more translatable preclinical research results, small animal irradiation needs to more closely simulate human radiotherapy. Although the clinical gold standard is intensity-modulated radiation therapy (IMRT), the direct translation of this method for small animals is impractical. In this study we des...

journal_title：Medical physics

authors： Woods K,Nguyen D,Neph R,Ruan D,O'Connor D,Sheng K

更新日期：2019-12-01 00:00:00

abstract：PURPOSE:Stringent quality assurance is required in MRI breast screening to ensure that different scanners and imaging protocols reach similar diagnostic performance. The authors propose a methodology, based on power spectrum analysis (PSA), to evaluate spatial resolution in clinical images. To demonstrate this approach...

journal_title：Medical physics

authors： Borri M,Scurr ED,Richardson C,Usher M,Leach MO,Schmidt MA

更新日期：2016-12-01 00:00:00

abstract：:Attenuation correction is an essential component of the long chain of data correction techniques required to achieve the full potential of quantitative positron emission tomography (PET) imaging. The development of combined PET/magnetic resonance imaging (MRI) systems mandated the widespread interest in developing nov...

journal_title：Medical physics

authors： Mehranian A,Arabi H,Zaidi H

更新日期：2016-03-01 00:00:00

abstract：PURPOSE:The purpose of this study was to develop a practical method for estimating organ doses from kilovoltage cone-beam CT (CBCT) that can be performed with readily available phantoms and dosimeters. The accuracy of organ dose estimates made using the ImPACT patient dose calculator was also evaluated. METHODS:A 100 ...

journal_title：Medical physics

authors： Hyer DE,Hintenlang DE

更新日期：2010-09-01 00:00:00

abstract：:A novel iterative penalized likelihood algorithm with evolutionary components for the optimization of beamlet fluences for intensity modulated radiation therapy (IMRT) is presented. This algorithm is designed to be flexible in terms of the objective function and automatically escalates dose, as long as the objective f...

journal_title：Medical physics

authors： Baydush AH,Marks LB,Das SK

更新日期：2004-08-01 00:00:00

abstract：:Accelerator-based neutron source have been considered to be practical for boron neutron capture therapy (BNCT). Based on experience with a parameters of the Brookhaven National Laboratory BMRR reactor neutron source, which has been used in treatment experiments, the future accelerator-based neutron source for BNCT sho...

journal_title：Medical physics

authors： Yu W,Yue G,Han X,Chen J,Tian B

更新日期：1998-07-01 00:00:00

abstract：PURPOSE:To experimentally commission a dual-energy CT (DECT) joint statistical image reconstruction (JSIR) method, which is built on a linear basis vector model (BVM) of material characterization, for proton stopping power ratio (SPR) estimation. METHODS:The JSIR-BVM method builds on the relationship between the energ...

journal_title：Medical physics

authors： Zhang S,Han D,Williamson JF,Zhao T,Politte DG,Whiting BR,O'Sullivan JA

更新日期：2019-01-01 00:00:00

abstract：:Modern linear accelerators contain multiple isocentres, defined by the mechanical motions of gantry, collimator and table. Isocentre localization for these motions has been performed using film and manual evaluations which have difficulty in relating the individual motions. To address these limitations, we have develo...

journal_title：Medical physics

authors： Heaton R,Smale J,Norrlinger B,Wang Y,van Prooijen M,Islam M

更新日期：2008-07-01 00:00:00

abstract：:The gamma-ray dose component of a d(80) + Be neutron beam was measured with a 6Li-shielded Geiger-Mueller counter in a tissue-equivalent liquid phantom. The proportion of gamma-ray dose to total dose increased from 0.07 near the surface to 0.09 at 25 cm depth. Due to thermal neutron sensitivity, the G-M count rate inc...

journal_title：Medical physics

authors： Harrison GH,Cox CR

更新日期：1979-05-01 00:00:00

abstract：:The modulation transfer function (MTF) of a screen-film system can be measured by two methods, i.e., a slit method with Fourier transform on the line spread function and a square-wave response function (SWRF) method. However, it is still uncertain whether MTFs obtained by the two methods are identical. In this study, ...

journal_title：Medical physics

authors： Morishita J,Doi K,Bollen R,Bunch PC,Hoeschen D,Sirand-rey G,Sukenobu Y

更新日期：1995-02-01 00:00:00

abstract：PURPOSE:To develop a novel aperture-based algorithm for volumetric modulated are therapy (VMAT) treatment plan optimization with high quality and high efficiency. METHODS:The VMAT optimization problem is formulated as a large-scale convex programming problem solved by a column generation approach. The authors consider...

journal_title：Medical physics

authors： Men C,Romeijn HE,Jia X,Jiang SB

更新日期：2010-11-01 00:00:00

abstract：:A method to correct for geometric image distortion in the x-ray imaging chain, so-called dewarping, has been developed. A global two-dimensional polynomial model of which the degree is optimized is used. The performance of the method has been tested in a number of experiments using images of a plate with a 1 cm spaced...

journal_title：Medical physics

authors： Gronenschild E

更新日期：1997-12-01 00:00:00

abstract：PURPOSE:To develop a probabilistic treatment planning (PTP) method which is robust to systematic patient setup errors and to compare PTP plans with plans generated using a planning target volume (PTV) margin optimized to give the same target coverage probability as the PTP plan. METHODS:Plans adhering to the RTOG-0126...

journal_title：Medical physics

authors： Moore JA,Gordon JJ,Anscher M,Silva J,Siebers JV

更新日期：2012-02-01 00:00:00

abstract：PURPOSE:To develop an automatic segmentation algorithm integrating imaging information from computed tomography (CT), positron emission tomography (PET), and magnetic resonance imaging (MRI) to delineate target volume in head and neck cancer radiotherapy. METHODS:Eleven patients with unresectable disease at the tonsil...

journal_title：Medical physics

authors： Yang J,Beadle BM,Garden AS,Schwartz DL,Aristophanous M

更新日期：2015-09-01 00:00:00