115In as a probe for the characterization of therapy bremsstrahlung beams and the detection of photoneutrons.

abstract：PURPOSE:The Imaging and Radiation Oncology Core Houston (IROC-H) (formerly the Radiological Physics Center) has reported varying levels of agreement in their anthropomorphic phantom audits. There is reason to believe one source of error in this observed disagreement is the accuracy of the dose calculation algorithms an...

journal_title：Medical physics

authors： Faught AM,Davidson SE,Fontenot J,Kry SF,Etzel C,Ibbott GS,Followill DS

更新日期：2017-09-01 00:00:00

abstract：PURPOSE:To investigate the critical structure sparing achievable by biological optimization for modulated volumetric arc (VMAT) of head and neck (H&N) cancer. METHODS:Ten H&N VMAT patients who were originally planned and treated with simultaneous integrated boost technique using dose-volume based optimization, were se...

journal_title：Medical physics

authors： Dogan N,Wu Y

更新日期：2012-06-01 00:00:00

abstract：:Numerical reconstruction of x-ray spectra from narrow-beam transmission data was tested with published spectra in the range from 45 to 100 kVp. Transmission curves were calculated from the spectra to simulate measured data. Spectra were reconstructed from these transmission curves with use of an iterative numerical an...

journal_title：Medical physics

authors： Huang PH,Chen TS,Kase KR

更新日期：1986-09-01 00:00:00

abstract：PURPOSE:To investigate tight-frame based iterative reconstruction (TFIR) technique for spectral breast computed tomography (CT) using fewer projections while achieving greater image quality. METHODS:The experimental data were acquired with a fan-beam breast CT system based on a cadmium zinc telluride photon-counting d...

journal_title：Medical physics

authors： Zhao B,Gao H,Ding H,Molloi S

更新日期：2013-03-01 00:00:00

abstract：:A commercially available open MRI unit is under routine use for radiation therapy simulation. The effects of a gradient distortion correction (GDC) program used to post process the images were assessed by comparison with the known geometry of a phantom. The GDC reduced the magnitude of the distortions at the periphery...

journal_title：Medical physics

authors： Mah D,Steckner M,Palacio E,Mitra R,Richardson T,Hanks GE

更新日期：2002-11-01 00:00:00

abstract：PURPOSE:To assess the temporal and spatial accuracy of the GateCT™ system (VisionRT, London, UK), a recently released respiratory tracking system for 4DCT, under both ideal and nonideal respiratory conditions. METHODS:Three experiments were performed by benchmarking and comparing its results with the ground-truth inpu...

journal_title：Medical physics

authors： Kauweloa KI,Ruan D,Park JC,Sandhu A,Kim GY,Pawlicki T,Watkins WT,Song B,Song WY

更新日期：2012-01-01 00:00:00

abstract：PURPOSE:To automatically and efficiently segment the lesion area of the colonoscopy polyp image, a polyp segmentation method has been presented. METHODS:An ensemble model of pretrained convolutional neural networks was proposed, using Unet-VGG, SegNet-VGG, and PSPNet. Firstly, the Unet-VGG is obtained by the first 10 ...

journal_title：Medical physics

authors： Guo X,Zhang N,Guo J,Zhang H,Hao Y,Hang J

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：PURPOSE:A joint working group was created by the American Association of Physicists in Medicine (AAPM), the European Society for Radiotherapy and Oncology (ESTRO), and the Australasian Brachytherapy Group (ABG) with the charge, among others, to develop a set of well-defined test case plans and perform calculations and ...

journal_title：Medical physics

authors： Ma Y,Vijande J,Ballester F,Tedgren ÅC,Granero D,Haworth A,Mourtada F,Fonseca GP,Zourari K,Papagiannis P,Rivard MJ,Siebert FA,Sloboda RS,Smith R,Chamberland MJP,Thomson RM,Verhaegen F,Beaulieu L

更新日期：2017-11-01 00:00:00

abstract：PURPOSE:Intensity modulated proton therapy (IMPT) of head and neck (H&N) cancer patients may be improved by plan adaptation. The decision to adapt the treatment plan based on a dose recalculation on the current anatomy requires a diagnostic quality computed tomography (CT) scan of the patient. As gantry-mounted cone be...

journal_title：Medical physics

authors： Landry G,Nijhuis R,Dedes G,Handrack J,Thieke C,Janssens G,Orban de Xivry J,Reiner M,Kamp F,Wilkens JJ,Paganelli C,Riboldi M,Baroni G,Ganswindt U,Belka C,Parodi K

更新日期：2015-03-01 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：:The effects of small cavities on dose in water and the dose in a homogeneous nonunit density medium illustrate that inhomogeneities do not act independently in photon dose perturbation, and serve as two constraints which should be satisfied by approximate methods of computed tomography (CT) pixel-based dose calculatio...

journal_title：Medical physics

authors： Wong JW,Henkelman RM

更新日期：1983-03-01 00:00:00

abstract：:This paper investigates the effect of the waterproofing sleeve on the calibration of kilovoltage photon beams (50-300 kV). The sleeve effect correction factor, ps has been calculated using the Monte Carlo method as the ratios of the air kerma in an air cavity of a cylindrical chamber without the waterproofing sleeve t...

journal_title：Medical physics

authors： Ma CM,Seuntjens JP

更新日期：1997-09-01 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：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：:An analytic representation proposed for the relative intensity distribution of the extra-focal source in a two-component x-ray source model serves as the basis for calculation. From this representation, a closed-form expression for head scatter factors defined on the central beam axis is derived by integrating over th...

journal_title：Medical physics

authors： Yu MK,Sloboda R

更新日期：1995-12-01 00:00:00

abstract：PURPOSE:In this work, the fabrication, operation, and evaluation of a probe-format graphite calorimeter - herein referred to as Aerrow - as an absolute clinical dosimeter of high-energy photon beams while in the presence of a B = 1.5 T magnetic field is described. Comparable to a cylindrical ionization chamber (IC) in ...

journal_title：Medical physics

authors： Renaud J,Sarfehnia A,Bancheri J,Seuntjens J

更新日期：2020-03-01 00:00:00

abstract：PURPOSE:Respiratory motion compensation in PET/CT and PET/MRI is essential as motion is a source of image degradation (motion blur, attenuation artifacts). In previous work, we developed a direct method for joint image reconstruction/motion estimation (JRM) for attenuation-corrected (AC) respiratory-gated PET, which us...

journal_title：Medical physics

authors： Bousse A,Manber R,Holman BF,Atkinson D,Arridge S,Ourselin S,Hutton BF,Thielemans K

更新日期：2017-06-01 00:00:00

abstract：PURPOSE:To provide a cascaded-systems framework based on the noise-power spectrum (NPS), modulation transfer function (MTF), and noise-equivalent number of quanta (NEQ) for quantitative evaluation of differential phase-contrast imaging (Talbot interferometry) in relation to conventional absorption contrast under equal-...

journal_title：Medical physics

authors： Fredenberg E,Danielsson M,Stayman JW,Siewerdsen JH,Aslund M

更新日期：2012-09-01 00:00:00

abstract：:Imaging parameters associated with a clinical magnetic resonance imaging (MRI) system, evaluated with the use of simple and inexpensive phantoms, are described in evaluation of a clinical MRI system. Images, obtained with a Diasonics 0.35-T MRI system using an elliptical whole-body radio frequency coil, are presented ...

journal_title：Medical physics

authors： Brateman L,Jennings LW,Nunnally RL,Vaughan JT

更新日期：1986-07-01 00:00:00

abstract：PURPOSE:Positron emission tomography (PET) is considered the gold standard for measuring myocardial blood flow in vivo but it is known that respiratory motion can lead to misalignment of the PET and computed tomography (CT) data sets and introduce artifacts in the CT-based attenuation correction (AC) of images. In addi...

journal_title：Medical physics

authors： Pourmoghaddas A,Klein R,deKemp RA,Wells RG

更新日期：2013-02-01 00:00:00

abstract：PURPOSE:To investigate the feasibility of using the high Zeff storage phosphor material BaFBrI:Eu2+ in conjunction with the low Zeff storage phosphor material KCl:Eu2+ for simultaneous proton dose and linear energy transfer (LET) measurements by 1) measuring the fundamental optical and dosimetric properties of BaFBrI:E...

journal_title：Medical physics

authors： Setianegara J,Mazur TR,Yang D,Li HH

更新日期：2021-02-01 00:00:00

abstract：PURPOSE:Silicon photodetectors are of significant interest for use in positron emission tomography (PET) systems due to their compact size, insensitivity to magnetic fields, and high quantum efficiency. However, one of their main disadvantages is fluctuations in temperature cause strong shifts in gain of the devices. P...

journal_title：Medical physics

authors： Freese DL,Vandenbroucke A,Innes D,Lau FW,Hsu DF,Reynolds PD,Levin CS

更新日期：2015-01-01 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：:Flat-panel imagers consisting of the first large area, self-scanning, pixelated, solid-state arrays made with hydrogenated amorphous silicon (a-Si:H) are under development by the authors for applications in diagnostic x-ray and megavoltage radiotherapy imaging. The arrays, designated by the acronym MASDA for multi-ele...

journal_title：Medical physics

authors： Antonuk LE,Boudry J,Huang W,McShan DL,Morton EJ,Yorkston J,Longo MJ,Street RA

更新日期：1992-11-01 00:00:00

abstract：PURPOSE:Particle therapy is becoming increasingly available world-wide for precise tumor targeting, its favorable depth dose deposition, and increased biological damage to tumor tissue compared to conventional photon therapy. As demand increases for improved robustness and conformality, next-generation secondary dose c...

journal_title：Medical physics

authors： Kopp B,Fuglsang Jensen M,Mein S,Hoffmann L,Nyström H,Falk M,Haberer T,Abdollahi A,Debus J,Mairani A

更新日期：2020-10-01 00:00:00

abstract：:Methods for scatter dose calculations in brachytherapy have been developed based on the collapsed cone superposition algorithm. The methods account for effects on the scatter dose caused by the three-dimensional distribution of heterogeneities in the irradiated volume and are considerably faster than methods based on ...

journal_title：Medical physics

authors： Carlsson AK,Ahnesjö A

更新日期：2000-10-01 00:00:00

abstract：PURPOSE:Photon counting arrays (PCAs), capable of measuring the spectral information of individual x-ray photons and recording that information digitally, provide a number of advantages compared to conventional, energy-integrating active matrix flat-panel imagers - such as reducing the undesirable effects of electronic...

journal_title：Medical physics

authors： Liang AK,Koniczek M,Antonuk LE,El-Mohri Y,Zhao Q

更新日期：2018-10-01 00:00:00

abstract：PURPOSE:The objective of this study is to evaluate requirements for radionuclide-based solid tumor therapy by assessing the radial dose distribution of beta-particle-emitting and alpha-particle-emitting molecules localized either solely within endothelial cells of tumor vasculature or diffusing from the vasculature thr...

journal_title：Medical physics

authors： Zhu X,Palmer MR,Makrigiorgos GM,Kassis AI

更新日期：2010-06-01 00:00:00

abstract：PURPOSE:The x-ray performance evaluation of digital x-ray detectors is based on the calculation of the modulation transfer function (MTF), the noise power spectrum (NPS), and the resultant detective quantum efficiency (DQE). The flat images used for the extraction of the NPS should not contain any fixed pattern noise (...

journal_title：Medical physics

authors： Konstantinidis AC,Olivo A,Speller RD

更新日期：2011-12-01 00:00:00