Investigation of basic imaging properties in digital radiography. 9. Effect of displayed grey levels on signal detection.

abstract：PURPOSE:The aim of this paper is to investigate the accuracy of a laser∕camera surface imaging system (Sentinel) when used on patients treated in the thorax or pelvic regions and to evaluate system employment conditions and patient setup procedures that provide more accurate results. METHODS:The system was tested on t...

journal_title：Medical physics

authors： Pallotta S,Simontacchi G,Marrazzo L,Ceroti M,Paiar F,Biti G,Bucciolini M

更新日期：2013-01-01 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:Imaging biomarkers are crucial in managing treatment options for cancer patients. They are extremely powerful tools since they allow personalized treatment assessment early during therapy by using repeated imaging to detect and quantify tumor response. Currently, treatment response assessment from consecutive i...

journal_title：Medical physics

authors： Schreibmann E,Waller AF,Crocker I,Curran W,Fox T

更新日期：2013-01-01 00:00:00

abstract：:We have developed a new method for optimization in intensity modulated radiation therapy (IMRT) that makes use of simulated dynamics in a classical system of interacting particles. An analogy is drawn between intensity profile optimization in IMRT and relaxation to the equilibrium configuration in a dynamic system. Th...

journal_title：Medical physics

authors： Hou Q,Wang J,Chen Y,Galvin JM

更新日期：2003-01-01 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：:The purpose of this study is to understand the effect of pitch on raw data interpolation in multislice spiral/helical computed tomography (CT) and provide guidelines for scanner design and protocol optimization. Multislice spiral CT is mainly characterized by the three parameters: the number of detector arrays, the de...

journal_title：Medical physics

authors： Wang G,Vannier MW

更新日期：1999-12-01 00:00:00

abstract：:An important point to consider in a brachytherapy dosimetry study is the phantom size involved in calculations or experimental measurements. As pointed out by Williamson [Med. Phys. 18, 776-786 (1991)] this topic has a relevant influence on final dosimetric results. Presently, one-dimensional (1-D) algorithms and newl...

journal_title：Medical physics

authors： Pérez-Calatayud J,Granero D,Ballester F

更新日期：2004-07-01 00:00:00

abstract：PURPOSE:Many biological objects, including neuronal dendrites, blood vasculature, airways, phylogenetic trees, produce tree structured data. Current methods of analysis either ignore the complex structure of trees or use distance-based methods which limit the scope of multivariate modeling. METHODS:We propose a branch...

journal_title：Medical physics

authors： Roy Choudhury K,Skwerer S

更新日期：2018-03-01 00:00:00

abstract：PURPOSE:The Nakagami statistical model and Nakagami shape parameter m have been widely used in linear tissue characterization and preliminarily characterized the envelope distributions of nonlinear encapsulated microbubbles (EMBs). However, the Nakagami distribution of nonlinear scattering EMBs lacked a systematical in...

journal_title：Medical physics

authors： Wang D,Sang Y,Zhang X,Hu H,Lu S,Zhang Y,Fu C,Cloutier G,Wan M

更新日期：2019-12-01 00:00:00

abstract：:The customization of brachytherapy dose distributions for gynecologic malignancies is limited by the spatial positioning of the applicators. We tested the hypothesis that applicator-guided intensity modulated radiation therapy (AGIMRT) has the potential to deliver highly conformal dose distributions to cervical tumors...

journal_title：Medical physics

authors： Wahab SH,Malyapa RS,Mutic S,Grigsby PW,Deasy JO,Miller TR,Zoberi I,Low DA

更新日期：2004-04-01 00:00:00

abstract：:To more accurately and precisely delineate a tumor in a 3D PET image, we proposed a novel, semi-automatic, two-stage method by utilizing an adaptive region-growing algorithm and a dual-front active contour model. First, a rough region of interest (ROI) is manually drawn by a radiation oncologist that encloses a tumor....

journal_title：Medical physics

authors： Li H,Thorstad WL,Biehl KJ,Laforest R,Su Y,Shoghi KI,Donnelly ED,Low DA,Lu W

更新日期：2008-08-01 00:00:00

abstract：PURPOSE:Accurate, patient-specific radiation dosimetry for CT scanning is critical to optimize radiation doses and balance dose against image quality. While Monte Carlo (MC) simulation is often used to estimate doses from CT, comparison of estimates to experimentally measured values is lacking for advanced CT scanners ...

journal_title：Medical physics

authors： Prinsen P,Trattner S,Wiegert J,Gerland EL,Shefer E,Morton T,Thompson CM,Cheng B,Halliburton SS,Einstein AJ

更新日期：2019-11-01 00:00:00

abstract：:In a recent paper of Miller et al. (Med. Phys. 43(5), 2141-2152 (2016), the voltage dependence polarity effect of microionization chambers was studied. It was identified that polarity effect arises from the difference in electric potential between the collecting electrode and the guard electrode, which in turn deforms...

journal_title：Medical physics

authors： Brivio D,Sajo E,Zygmanski P

更新日期：2017-03-01 00:00:00

abstract：PURPOSE:In computed tomography (CT), organ dose, effective dose, and risk index can be estimated from volume-weighted CT dose index (CTDI(vol)) or dose-length product (DLP) using conversion coefficients. Studies have investigated how these coefficients vary across scanner models, scan parameters, and patient size. Howe...

journal_title：Medical physics

authors： Li X,Samei E,Williams CH,Segars WP,Tward DJ,Miller MI,Ratnanather JT,Paulson EK,Frush DP

更新日期：2012-11-01 00:00:00

abstract：:The dose distribution for an ovoid with a new tungsten shielding design was determined using Monte Carlo simulation. Standard Cesium-137 tube sources, tungsten shielding, and aluminum ovoid applicator were each modeled as a collection of solid objects. Dose was calculated in planes above, below, in front of, and on th...

journal_title：Medical physics

authors： Weeks KJ

更新日期：1998-12-01 00:00:00

abstract：PURPOSE:Radiochromic film provides dose measurement at high spatial resolution, but often is not preferred for routine evaluation of patient-specific intensity modulated radiation therapy (IMRT) plans owing to ease-of-use factors. The authors have established an efficient protocol that combines calibration and measurem...

journal_title：Medical physics

authors： Lewis D,Micke A,Yu X,Chan MF

更新日期：2012-10-01 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：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：:This article provides a quantitative evaluation of Varian Medical Systems' beam matching procedure. A one-dimensional y analysis is employed to investigate the level of agreement of matched beams. A customized concept of one-dimensional gamma evaluation was designed. Our algorithm first performs a "local" fit of the r...

journal_title：Medical physics

authors： Hrbacek J,Depuydt T,Nulens A,Swinnen A,Van den Heuvel F

更新日期：2007-07-01 00:00:00

abstract：:A tomographic attachment was designed and developed that attaches to our existing simulator. The film tomograms obtained with the aid of this device exhibit very low geometrical distortion and good contrast and resolution for the objects used in this investigation. In addition, our results to date show that adjacent a...

journal_title：Medical physics

authors： Kessaris ND,Harisiadis L

更新日期：1980-03-01 00:00:00

abstract：:Reported MOSFET measurements concern mostly external radiotherapy and in vivo dosimetry. In this paper, we apply the technique for absolute dosimetry in the context of HDR brachytherapy using an 192Ir source. Measured radial dose rate distributions in water for different planes perpendicular to the source axis are pre...

journal_title：Medical physics

authors： Zilio VO,Joneja OP,Popowski Y,Rosenfeld A,Chawla R

更新日期：2006-06-01 00:00:00

abstract：PURPOSE:The purpose of this study was to describe and evaluate methods for calculating a megavoltage computed tomography (MVCT)-derived MR hardware attenuation map (μ-map) and dual-energy CT (DECT) for 511 keV photons. METHODS:Phantom measurements were acquired on a whole-body hybrid PET/MRI system, using a four-chann...

journal_title：Medical physics

authors： Patrick JC,Terry Thompson R,So A,Butler J,Faul D,Stodilka RZ,Yartsev S,Prato FS,Gaede S

更新日期：2017-09-01 00:00:00

abstract：PURPOSE:To present EBT2 film verification of treatment planning with the eXtend System, a relocatable frame system for multiple-fraction or serial multiple-session radiosurgery. METHODS:A human head shaped phantom simulated the verification process for fractionated Gamma Knife (GK) treatment. Phantom preparation for e...

journal_title：Medical physics

authors： Gopishankar N,Bisht RK

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:To evaluate the performance and efficacy for intensity inhomogeneity correction of various sequences of the human brain in 7T MRI using the extended version of the unified segmentation algorithm. MATERIALS:Ten healthy volunteers were scanned with four different sequences (2D spin echo [SE], 3D fast SE, 2D fast...

journal_title：Medical physics

authors： Uwano I,Kudo K,Yamashita F,Goodwin J,Higuchi S,Ito K,Harada T,Ogawa A,Sasaki M

更新日期：2014-02-01 00:00:00

abstract：PURPOSE:To describe an efficient method for verifying the size and centering of the radiation field from the Cyberknife IRIS variable collimator with sub-millimeter accuracy using a general purpose commercially available diode array. METHODS:We present a technique using a conventional diode array (Sun Nuclear Profiler...

journal_title：Medical physics

authors： Gibbs G,White G,Bulz G

更新日期：2012-06-01 00:00:00

abstract：:Our purpose in this work is to demonstrate that the efficiency of dose-rate computations in 125I brachytherapy, using multigroup discrete ordinates radiation transport simulations, can be significantly enhanced using broad energy group cross sections without a loss of accuracy. To this end, the DANTSYS multigroup disc...

journal_title：Medical physics

authors： Daskalov GM,Baker RS,Rogers DW,Williamson JF

更新日期：2002-02-01 00:00:00

abstract：PURPOSE:To provide results of water calorimetry and ion chamber measurements in high-energy electron beams carried out at the National Research Council Canada (NRC). There are three main aspects to this work: (a) investigation of the behavior of ionization chambers in electron beams of different energies with focus on ...

journal_title：Medical physics

authors： Muir BR,Cojocaru CD,McEwen MR,Ross CK

更新日期：2017-10-01 00:00:00

abstract：PURPOSE:The extensive use of computed tomography (CT) in diagnostic procedures is accompanied by a growing need for more accurate and patient-specific dosimetry techniques. Optically stimulated luminescent dosimeters (OSLDs) offer a potential solution for patient-specific CT point-based surface dosimetry by measuring a...

journal_title：Medical physics

authors： Scarboro SB,Cody D,Alvarez P,Followill D,Court L,Stingo FC,Zhang D,McNitt-Gray M,Kry SF

更新日期：2015-04-01 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：:A new type of radiographic film, EDR (extended dose range) film, has been recently become available for film dosimetry. It is particularly attractive for composite isodose verification of intensity modulated radiation therapy because of its low sensitivity relative to the more common Kodak XV film. For XV film, the re...

journal_title：Medical physics

authors： Zhu XR,Yoo S,Jursinic PA,Grimm DF,Lopez F,Rownd JJ,Gillin MT

更新日期：2003-05-01 00:00:00