An automated procedure for the quality assurance of electron beam output and energy.

abstract：:Currently, patients with brain neoplasms must undergo both computed tomography (CT) and magnetic resonance (MR) imaging to take advantage of CT's density information and MR's soft tissue imaging capabilities. A method has been developed that allows virtual simulation, digitally reconstructed radiographs (DRRs), and 3-...

journal_title：Medical physics

authors： Ramsey CR,Oliver AL

更新日期：1998-10-01 00:00:00

abstract：:Stereotactic Body Radiation Therapy (SBRT) is being increasingly used in the radiation oncology community to treat tumors in extra-cranial sites such as spine, lung, liver, pancreas and prostate. There are well established RTOG protocols (e.g. RTOG 0631 for spine, RTOG 0813 and 0915 for lung and RTOG 0438 for liver) t...

journal_title：Medical physics

authors： Hong L

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：:It is shown that predictions can be made of scatter-to-primary ratios for a variety of mammographic configurations. The different configurations can be produced by changes in source-detector distance; source-phantom distance; air gap; photon energy; phantom composition, thickness, and cross-sectional area. A detailed ...

journal_title：Medical physics

authors： Bernstein H,Muntz EP

更新日期：1986-11-01 00:00:00

abstract：:Statistical image reconstruction (SIR) methods have shown potential to substantially improve the image quality of low-dose x-ray computed tomography (CT) as compared to the conventional filtered back-projection (FBP) method. According to the maximum a posteriori (MAP) estimation, the SIR methods are typically formulat...

journal_title：Medical physics

authors： Zhang H,Wang J,Zeng D,Tao X,Ma J

更新日期：2018-10-01 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 aim of the present study is to examine the validity of using silicon semiconductor detectors in degraded electron beams with a broad energy spectrum and a wide angular distribution. A comparison is made with diamond detector measurements, which is the dosimeter considered to give the best results provided that dos...

journal_title：Medical physics

authors： Björk P,Knöös T,Nilsson P

更新日期：2000-11-01 00:00:00

abstract：PURPOSE:To develop a new biological equivalent dose (BED) formulism that includes repair, repopulation and resensitization (redistribution and reoxygenation), and can be used to calculate prescribed dose for permanent implant with Cs-131. METHODS:Because of lack of sufficient clinical data, the prescribed dose with ne...

journal_title：Medical physics

authors： Luo W,Aryal P,Randall M

更新日期：2012-06-01 00:00:00

abstract：:Testing computer-controlled linear accelerators for patient safety and proper patient dose delivery requires that certain beam characteristics be monitored over an extended period of time. Computer-controlled conformal radiation therapy using asymmetric collimator jaw settings necessitates stable symmetric treatment b...

journal_title：Medical physics

authors： Loyd MD,Lane RG,Laxton J,Chow CH,Rosen II

更新日期：1989-07-01 00:00:00

abstract：PURPOSE:The ionizing radiation imparted to patients during computed tomography exams is raising concerns. This paper studies the performance of a scheme called dose reduction using prior image constrained compressed sensing (DR-PICCS). The purpose of this study is to characterize the effects of a statistical model of x...

journal_title：Medical physics

authors： Lauzier PT,Chen GH

更新日期：2013-02-01 00:00:00

abstract：PURPOSE:To develop and test the feasibility of a two-pass iterative reconstruction algorithm with material decomposition designed to obtain quantitative iodine measurements in digital breast tomosynthesis. METHODS:Contrast-enhanced mammography has shown promise as a cost-effective alternative to magnetic resonance ima...

journal_title：Medical physics

authors： Michielsen K,Rodríguez-Ruiz A,Reiser I,Nagy JG,Sechopoulos I

更新日期：2020-10-01 00:00:00

abstract：:A Monte Carlo method was developed and implemented to simulate x-ray photon transport. Simulations consisted of a pencil beam of monoenergetic photons with energies from 50 to 110 keV incident on water and aluminum slabs. The dependence of scatter fraction and multiple scattering on x-ray energy, scatterer thickness, ...

journal_title：Medical physics

authors： Papin PJ,Rielly PS

更新日期：1988-11-01 00:00:00

abstract：PURPOSE:Magnetic particle imaging (MPI) is a relatively new method to image the spatial distribution of magnetic nanoparticle (MNP) tracers administered to the body with high spatial and temporal resolution using an inhomogeneous magnetic field. The spatial information of the MNP's is encoded using a field free point (...

journal_title：Medical physics

authors： Top CB,Güngör A,Ilbey S,Güven HE

更新日期：2019-04-01 00:00:00

abstract：PURPOSE:Precise segmentation of clinical target volume (CTV) is the key to stomach cancer radiotherapy. We proposed a novel stochastic width - deep neural network (SW-DNN) for better automatically contouring stomach CTV METHODS: SW-DNN was an end-to-end approach, of which the core component was a novel SW mechanism tha...

journal_title：Medical physics

authors： Xu L,Hu J,Song Y,Bai S,Yi Z

更新日期：2021-01-27 00:00:00

abstract：PURPOSE:The purpose of this study is to adapt an equivalent source model originally developed for conventional CT Monte Carlo dose quantification to the radiation oncology context and validate its application for evaluating concomitant dose incurred by a kilovoltage (kV) cone-beam CT (CBCT) system integrated into a lin...

journal_title：Medical physics

authors： McMillan K,McNitt-Gray M,Ruan D

更新日期：2013-11-01 00:00:00

abstract：:The purpose of this work is to show the feasibility of using in vivo proton radiography of a radiotherapy patient for the patient individual optimization of the calibration from CT-Hounsfield units to relative proton stopping power. Water equivalent tissue (WET) calibrated proton radiographs of a dog patient treated f...

journal_title：Medical physics

authors： Schneider U,Pemler P,Besserer J,Pedroni E,Lomax A,Kaser-Hotz B

更新日期：2005-01-01 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:At our institution, all proton patient plans undergo patient-specific quality assurance (PSQA) prior to treatment delivery. For intensity-modulated proton beam therapy, quality assurance is complex and time consuming, and it may involve multiple measurements per field. We reviewed our PSQA workflow and identifi...

journal_title：Medical physics

authors： Hernandez Morales D,Shan J,Liu W,Augustine KE,Bues M,Davis MJ,Fatyga M,Johnson JE,Mundy DW,Shen J,Younkin JE,Stoker JB

更新日期：2019-01-01 00:00:00

abstract：PURPOSE:To describe and mathematically validate the superiorization methodology, which is a recently developed heuristic approach to optimization, and to discuss its applicability to medical physics problem formulations that specify the desired solution (of physically given or otherwise obtained constraints) by an opti...

journal_title：Medical physics

authors： Herman GT,Garduno E,Davidi R,Censor Y

更新日期：2012-09-01 00:00:00

abstract：PURPOSE:Dynamic myocardial perfusion computed tomography (DM-PCT) imaging offers benefits over quantitative assessment of myocardial blood flow (MBF) for diagnosis and risk stratification of coronary artery disease. However, one major drawback of DM-PCT imaging is that a high radiation level is imparted by repeated sca...

journal_title：Medical physics

authors： Bian Z,Zeng D,Zhang Z,Gong C,Tian X,Yan G,Huang J,Guo H,Chen B,Zhang J,Feng Q,Chen W,Ma J

更新日期：2017-09-01 00:00:00

abstract：PURPOSE:Wide bore CT scanners use extended field-of-view (eFOV) reconstruction algorithms to attempt to recreate tissue truncated due to large patient habitus. Radiation therapy planning systems rely on accurate CT numbers in order to correctly plan and calculate radiation dose. This study looks at the impact of eFOV r...

journal_title：Medical physics

authors： Cheung JP,Shugard E,Mistry N,Pouliot J,Chen J

更新日期：2019-02-01 00:00:00

abstract：:Measurements of a 670-MeV/amu 20Ne beam at the Lawrence Berkeley Laboratory Bevalac heavy-ion accelerator with various thicknesses of water absorber were obtained with the BERKLET. The BERKLET, a simple three-stage solid-state telescope detector, has been described previously. This instrument measures the linear energ...

journal_title：Medical physics

authors： Llacer J,Schmidt JB,Tobias CA

更新日期：1990-03-01 00:00:00

abstract：PURPOSE:Concurrent irradiation of the prostate and pelvic lymph nodes is technically challenging due to treating one moving target and one immobile target. The purposes of this article are to propose a new management strategy and to compare this strategy to the conventional isocenter shift method and the previously pro...

journal_title：Medical physics

authors： Xia P,Qi P,Hwang A,Kinsey E,Pouliot J,Roach M 3rd

更新日期：2010-09-01 00:00:00

abstract：:An addendum to the AAPM's TG-51 protocol for the determination of absorbed dose to water in megavoltage photon beams is presented. This addendum continues the procedure laid out in TG-51 but new kQ data for photon beams, based on Monte Carlo simulations, are presented and recommendations are given to improve the accur...

journal_title：Medical physics

authors： McEwen M,DeWerd L,Ibbott G,Followill D,Rogers DW,Seltzer S,Seuntjens J

更新日期：2014-04-01 00:00:00

abstract：PURPOSE:Accurately predicting outcome (i.e., overall survival (OS) time) for higher grade glioma (HGG) has great clinical value and would provide optimized guidelines for treatment planning. Radiomics focuses on revealing underlying pathophysiological information in biomedical images for disease analysis and demonstrat...

journal_title：Medical physics

authors： Wu G,Shi Z,Chen Y,Wang Y,Yu J,Lv X,Chen L,Ju X,Chen Z

更新日期：2019-01-01 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:Researchers write many computer programs with unique implementations, usually requiring a great amount of effort for other researchers to learn how to install, configure, and use. Some programs require specialized hardware platforms such as GPU workstation or CPU cluster, which may not readily available for man...

journal_title：Medical physics

authors： Folkerts M,Graves Y,Gautier Q,Kim G,Jia X,Jiang S

更新日期：2012-06-01 00:00:00

abstract：:A commercial optical system developed by Solid Photography, Inc., has been used to generate precise paraffin--polyethylene tissue compensators. A program with the objective of constructing a medical facility has been undertaken to access patient topology for treatment planning, tissue-compensator fabrication, and pati...

journal_title：Medical physics

authors： Lerch IA,Barish RJ,Stern H

更新日期：1978-11-01 00:00:00

abstract：:We propose the use of conic and cubic surface equations (surfaces of second and third order) to directly approximate the dual-energy equations (the integral equations for the dual-energy log-signal functions, i.e., the negative logarithms of the relative detector signals, considered as functions of the basis-material ...

journal_title：Medical physics

authors： Cardinal HN,Fenster A

更新日期：1990-05-01 00:00:00

abstract：:The observation of scattered radiations of larger wavelength than the primary had been repeatedly rejected or explained away by many researchers, including Compton. After years of vacillations, he recognized the effect named after him and was the first to develop a quantal equation predicting the wavelength of scatter...

journal_title：Medical physics

authors： del Regato JA

更新日期：1981-11-01 00:00:00