Characterization of scintillator-based detectors for few-ten-keV high-spatial-resolution x-ray imaging.

abstract：:Electron energy spectra and angular distributions, including angular spreads, were measured using magnetic spectrometer techniques, at isocenter, for two clinical linear accelerators: one scanning beam machine, which achieves field flatness by scanning a pencil beam over the desired field at the patient plane, and one...

journal_title：Medical physics

authors： Deasy JO,Almond PR,McEllistrem MT

更新日期：1996-05-01 00:00:00

abstract：PURPOSE:Timely identification of systematic changes in radiation delivery of an imaging system can lead to a reduction in risk for the patients involved. However, existing quality assurance programs involving the routine testing of equipment performance using phantoms are limited in their ability to effectively carry o...

journal_title：Medical physics

authors： Stevens NT,Steiner SH,Smith IR,MacKay RJ

更新日期：2011-01-01 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:To develop and evaluate the impact on lesion conspicuity of a software-based x-ray scatter correction algorithm for digital breast tomosynthesis (DBT) imaging into which a precomputed library of x-ray scatter maps is incorporated. METHODS:A previously developed model of compressed breast shapes undergoing mamm...

journal_title：Medical physics

authors： Feng SS,D'Orsi CJ,Newell MS,Seidel RL,Patel B,Sechopoulos I

更新日期：2014-03-01 00:00:00

abstract：PURPOSE:A new technique called "curvilinear approach" for prostate seed implantation has been proposed. The purpose of this study is to evaluate the dosimetric benefit of curvilinear distribution of seeds for low-dose-rate (LDR) prostate brachytherapy. METHODS:Twenty LDR prostate brachytherapy cases planned intraopera...

journal_title：Medical physics

authors： Podder TK,Dicker AP,Hutapea P,Darvish K,Yu Y

更新日期：2012-04-01 00:00:00

abstract：:We report on some extensions and further developments of a well-known microcalcification detection algorithm based on adaptive noise equalization. Tissue equivalent phantom images with and without labeled microcalcifications were subjected to this algorithm, and analyses of results revealed some shortcomings in the ap...

journal_title：Medical physics

authors： Gürün OO,Fatouros PP,Kuhn GM,de Paredes ES

更新日期：2001-04-01 00:00:00

abstract：PURPOSE:Monte Carlo (MC) dose calculation is generally superior to analytical dose calculation (ADC) used in commercial TPS to model the dose distribution especially for heterogeneous sites, such as lung and head/neck patients. The purpose of this study was to provide a validated, fast, and open-source MC code, MCsquar...

journal_title：Medical physics

authors： Huang S,Souris K,Li S,Kang M,Barragan Montero AM,Janssens G,Lin A,Garver E,Ainsley C,Taylor P,Xiao Y,Lin L

更新日期：2018-12-01 00:00:00

abstract：PURPOSE:Partial scan reconstruction (PSR) artifacts are present in myocardial perfusion imaging using dynamic multidetector computed tomography (MDCT). PSR artifacts appear as temporal CT number variations due to inconsistencies in the angular data range used to reconstruct images and compromise the quantitative value ...

journal_title：Medical physics

authors： Ramirez-Giraldo JC,Yu L,Kantor B,Ritman EL,McCollough CH

更新日期：2012-01-01 00:00:00

abstract：:An energy discriminating detector for dual-energy radiography can be configured as a two-layer sandwich, where the mean energy of photons detected by the two layers differs. To characterize the quantum noise of such a detector, the noise covariance between the two layers must be known in addition to the noise variance...

journal_title：Medical physics

authors： Sones RA,Barnes GT

更新日期：1989-11-01 00:00:00

abstract：:During the past decade the use of undersampled acquisition and constrained reconstruction have led to significant increases in data acquisition speed, SNR, spatial resolution and temporal resolution in MR imaging. When a separately acquired constraining image is combined with an angiographic time series the traditiona...

journal_title：Medical physics

authors： Mistretta C

更新日期：2012-06-01 00:00:00

abstract：:This study evaluates the effects of respiratory motion on breast radiotherapy delivered using segmented multileaf collimator (SMLC) intensity modulation. An anthropomorphic breast phantom was constructed of polystyrene plates between which radiographic films were inserted. The phantom was mounted on a moving platform ...

journal_title：Medical physics

authors： Liu Q,McDermott P,Burmeister J

更新日期：2007-01-01 00:00:00

abstract：:Amorphous selenium (a-Se) based real-time flat-panel imagers (FPIs) are finding their way into the digital radiology department because they offer the practical advantages of digital x-ray imaging combined with an image quality that equals or outperforms that of conventional systems. The temporal imaging characteristi...

journal_title：Medical physics

authors： Rau AW,Bakueva L,Rowlands JA

更新日期：2005-10-01 00:00:00

abstract：PURPOSE:Repeated brain MRI scans are performed in many clinical scenarios, such as follow up of patients with tumors and therapy response assessment. In this paper, the authors show an approach to utilize former scans of the patient for the acceleration of repeated MRI scans. METHODS:The proposed approach utilizes the...

journal_title：Medical physics

authors： Weizman L,Eldar YC,Ben Bashat D

更新日期：2015-09-01 00:00:00

abstract：PURPOSE:The purpose of this work was to examine the suitability of VIPARnd polymer gel-9.4 T magnetic resonance microimaging system for high spatial resolution dose distribution measurements. METHODS:The VIPARnd samples (3 cm in outside diameter and 12 cm in height) were exposed to ionizing radiation by using a linear...

journal_title：Medical physics

authors： Skorupa A,Woźnica A,Ciszek M,Staniszewski M,Kijonka M,Kozicki M,Woźniak B,Orlef A,Polański A,Boguszewicz Ł,Sokół M

更新日期：2020-08-01 00:00:00

abstract：PURPOSE:To provide specific experience-based guidance and recommendations for centers wishing to develop, validate, and implement an accurate and efficient process for directly using positron emission tomography-computed tomography (PET-CT) for the radiotherapy planning of head and neck cancer patients. METHODS:A PET-...

journal_title：Medical physics

authors： Thomas CM,Pike LC,Hartill CE,Baker S,Woods E,Convery DJ,Greener AG

更新日期：2014-04-01 00:00:00

abstract：PURPOSE:The fundamental nature of positron emission tomography (PET), as an event detection system, provides some flexibility for data handling, including retrospective data manipulation. The reorganization of acquisition data allows the emulation of new scans arising from identical radiotracer spatial distributions, b...

journal_title：Medical physics

authors： Schaefferkoetter J,Nai YH,Reilhac A,Townsend DW,Eriksson L,Conti M

更新日期：2019-06-01 00:00:00

abstract：PURPOSE:Commercially available fillable plastic inserts used in positron emission tomography phantoms usually have thick plastic walls, separating their content from the background activity. These "cold" walls can modify the intensity values of neighboring active regions due to the partial volume effect, resulting in e...

journal_title：Medical physics

authors： Berthon B,Marshall C,Edwards A,Evans M,Spezi E

更新日期：2013-08-01 00:00:00

abstract：PURPOSE:Integrating a linac with a magnetic resonance imager (MRI) will revolutionize the accuracy of external beam radiation treatments. Irradiating in the presence of a strong magnetic field, however, will modify the dose distribution. These dose modifications have been investigated previously, mainly using Monte Car...

journal_title：Medical physics

authors： Ghila A,Steciw S,Fallone BG,Rathee S

更新日期：2017-09-01 00:00:00

abstract：PURPOSE:Although x-ray projection mammography has been very effective in early detection of breast cancer, its utility is reduced in the detection of small lesions that are occult or in dense breasts. One drawback is that the inherent superposition of parenchymal structures makes visualization of small lesions difficul...

journal_title：Medical physics

authors： Le Huy Q,Ducote JL,Molloi S

更新日期：2010-03-01 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:The goal of this work is to propose a new multichannel method correcting for systematic thickness disturbances and to evaluate its precision in relevant radiation dosimetry applications. METHODS:The eigencolor ratio technique is introduced and theoretically developed to provide a method correcting for thicknes...

journal_title：Medical physics

authors： Bouchard H,Billas I,Subie A,Duane S

更新日期：2021-02-01 00:00:00

abstract：PURPOSE:Brachytherapy with 106 Ru/106 Rh plaques offers good outcomes for small-to-medium choroidal melanomas and retinoblastomas. The dose measurement of the plaques is challenging, due to the small range of the emitted beta particles and steep dose gradients involved. The scarce publications on film dosimetry of 106 ...

journal_title：Medical physics

authors： Hermida-López M,Brualla L

更新日期：2018-04-01 00:00:00

abstract：:Segmentation of the lungs within magnetic resonance (MR) scans is a necessary step in the computer-based analysis of thoracic MR images. This process is often confounded by image acquisition artifacts and disease-induced morphological deformation. We have developed an automated method for lung segmentation that is ins...

journal_title：Medical physics

authors： Sensakovic WF,Armato SG 3rd,Starkey A,Caligiuri P

更新日期：2006-09-01 00:00:00

abstract：:Increasing output resolution is assumed to improve noise characteristics of a CCD digitizer. In this work, however, we have found that as the quantization step becomes lower than the analog noise (present in the signal before its conversion to digital) the noise reduction becomes significantly lower than expected. Tha...

journal_title：Medical physics

authors： González A,Martínez JA,Tobarra B

更新日期：2004-03-01 00:00:00

abstract：:An indirect flat panel imager (FPI) with programmable avalanche gain and field emitter array (FEA) readout is being investigated for low-dose and high resolution x-ray imaging. It is made by optically coupling a structured x-ray scintillator, e.g., thallium (Tl) doped cesium iodide (CsI), to an amorphous selenium (a-S...

journal_title：Medical physics

authors： Li D,Zhao W

更新日期：2008-07-01 00:00:00

abstract：PURPOSE:The purpose of this study was to investigate the potential of MR-guided pulsed focused ultrasound (pFUS) for the enhancement of drug uptake in prostate tumors in vivo using doxorubicin (Dox). METHODS:An antitumor drug Dox, an orthotopic animal prostate tumor model using human prostate cancer, LNCaP cell line, ...

journal_title：Medical physics

authors： Chen X,Cvetkovic D,Ma CM,Chen L

更新日期：2012-05-01 00:00:00

abstract：PURPOSE:Formation of new blood vessels (angiogenesis) in response to hypoxia is a fundamental event in the process of tumor growth and metastatic dissemination. However, abnormalities in tumor neovasculature often induce increased interstitial pressure (IP) and further reduce oxygenation (pO2) of tumor cells. In radiot...

journal_title：Medical physics

authors： Lagerlöf JH,Kindblom J,Bernhardt P

更新日期：2011-08-01 00:00:00

abstract：PURPOSE:Periodic MV∕KV radiographs taken during volumetric modulated arc therapy (VMAT) for hypofractionated treatment provide guidance in intrafractional motion management. The choice of imaging frequency and timing are key components in delivering the desired dose while reducing associated overhead such as imaging do...

journal_title：Medical physics

authors： Zhang P,Hunt M,Happersett L,Cox B,Mageras G

更新日期：2012-09-01 00:00:00

abstract：PURPOSE:To review the issues a physicist may encounter in a community hospital during the transition from film/paper charts to a paperless environment with ARIA and a TrueBeam LINAC. With a lean budget, it was necessary for the physics group to take on the project management responsibilities in order save costs. This w...

journal_title：Medical physics

authors： Chu K,Rasmussen B

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:The appearance of parenchymal∕stromal patterns in mammography have been characterized as having a Wiener power spectrum with an inverse power-law shape described by the exponential parameter, β. The amount of fibroglandular tissue, which can be quantified in terms of volumetric breast density (VBD), influences ...

journal_title：Medical physics

authors： Mainprize JG,Tyson AH,Yaffe MJ

更新日期：2012-08-01 00:00:00