Generation of arbitrary intensity profiles by combining the scanning beam with dynamic multileaf collimation.

abstract：:Like Medical Physics, Imaging Informatics encompasses concepts touching every aspect of the imaging chain from image creation, acquisition, management and archival, to image processing, analysis, display and interpretation. The two disciplines are in fact quite complementary, with similar goals to improve the quality ...

journal_title：Medical physics

authors： Andriole K

更新日期：2012-06-01 00:00:00

abstract：:Cardiac arrhythmias are a major health burden, associated with reduced quality of life and substantial morbidity and mortality. Current therapy includes moderately effective medication and catheter-based ablation of arrhythmogenic substrates in the heart. Catheter interventions frequently have to be repeated due to re...

journal_title：Medical physics

authors： Graeff C,Bert C

更新日期：2018-11-01 00:00:00

abstract：:A Monte Carlo computer study of the total dose distribution from neutrons and prompt gamma emissions (but excluding the contribution from conversion and Auger electrons) for gadolinium neutron capture therapy of brain tumors has been carried out in order to test the theoretic feasibility of this modality using commerc...

journal_title：Medical physics

authors： Masiakowski JT,Horton JL,Peters LJ

更新日期：1992-09-01 00:00:00

abstract：:The widespread application of positron emission tomography (PET) in clinical oncology has driven this imaging technology into a number of new research and clinical arenas. Increasing numbers of patient scans have led to an urgent need for efficient data handling and the development of new image analysis techniques to ...

journal_title：Medical physics

authors： Montgomery DW,Amira A,Zaidi H

更新日期：2007-02-01 00:00:00

abstract：:DICOM format is the de facto standard for communications between therapeutic and diagnostic modalities. A plan generated by a treatment planning system (TPS) is often exported to DICOM format. BEAMnrc/DOSXYZnrc is a widely used Monte Carlo (MC) package for beam and dose simulations in radiotherapy. It has its own defi...

journal_title：Medical physics

authors： Zhan L,Jiang R,Osei EK

更新日期：2012-07-01 00:00:00

abstract：PURPOSE:To evaluate if the recently described problems with the calibration of jaws at Varian linear accelerators can be detected with the DAVID system. METHODS:Recently Varian Clinac field size issues resulted in a widespread medical device correction notice, stating that incorrect jaw positioning due to excessive co...

journal_title：Medical physics

authors： Poppe B,Looe H,Harder D

更新日期：2012-06-01 00:00:00

abstract：:Two new liquid ionization chamber (LIC) designs, consisting of cylindrical and plane-parallel configurations, are presented. They are designed to be suitable for high-precision measurements of absorbed dose-to-water at dose rates and photon energies typical for LDR intermediate photon energy brachytherapy sources. The...

journal_title：Medical physics

authors： Wickman G,Johansson B,Bahar-Gogani J,Holmström T,Grindborg JE

更新日期：1998-06-01 00:00:00

abstract：PURPOSE:Volumetric x-ray microcomputed tomography (CT) can be employed in a variety of quantitative research applications such as image-guided interventions or characterization of medical devices. To ensure the highest geometric fidelity of images for these applications, a phantom and image processing algorithm have be...

journal_title：Medical physics

authors： Waring CS,Bax JS,Samarabandu A,Holdsworth DW,Fenster A,Lacefield JC

更新日期：2012-10-01 00:00:00

abstract：PURPOSE:Electronic portal imagers (EPIDs) with high detective quantum efficiencies (DQEs) are sought to facilitate the use of the megavoltage (MV) radiotherapy treatment beam for image guidance. Potential advantages include high quality (treatment) beam's eye view imaging, and improved cone-beam computed tomography (CB...

journal_title：Medical physics

authors： Star-Lack J,Shedlock D,Swahn D,Humber D,Wang A,Hirsh H,Zentai G,Sawkey D,Kruger I,Sun M,Abel E,Virshup G,Shin M,Fahrig R

更新日期：2015-09-01 00:00:00

abstract：:Image correlation is often required to utilize the complementary information in CT, MRI, and SPECT. A practical method for automatic image correlation in three-dimensions (3D) based on chamfer matching is described. The method starts with automatic extraction of contour points in one modality and automatic segmentatio...

journal_title：Medical physics

authors： van Herk M,Kooy HM

更新日期：1994-07-01 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：PURPOSE:To investigate the difference of MR percent breast density measured from fat-suppressed versus nonfat-suppressed imaging sequences. METHODS:Breast magnetic resonance imaging (MRI) with and without fat suppression was acquired from 38 subjects. Breasts were divided into subgroups of different morphological patt...

journal_title：Medical physics

authors： Chang DH,Chen JH,Lin M,Bahri S,Yu HJ,Mehta RS,Nie K,Hsiang DJ,Nalcioglu O,Su MY

更新日期：2011-11-01 00:00:00

abstract：PURPOSE:To determine if NSCLC GTV CT textures can be predictive for tumor shrinkage after proton therapy with concurrent chemotherapy. METHODS:Simulation and weekly 4DCTs were obtained from 25 patients with locally advanced NSCLC treated by proton therapy at a 74 Gy dose level with concurrent chemotherapy. In-house de...

journal_title：Medical physics

authors： Hunter L,Chen Y,Zhang L,Liao Z,Dong L,Court L

更新日期：2012-06-01 00:00:00

abstract：:In this work, we present a calcification-detection scheme that automatically localizes calcifications in a previously detected cluster in order to generate the input for a cluster-classification scheme developed in the past. The calcification-detection scheme makes use of three pieces of a priori information: the loca...

journal_title：Medical physics

authors： Salfity MF,Nishikawa RM,Jiang Y,Papaioannou J

更新日期：2003-05-01 00:00:00

abstract：:The proper evaluation of the accuracy of a new computer program for radiation-therapy dosimetry requires consideration of both the mathematical algorithm used in the program and the performance required in clinical applications. As an example, our evaluation of the irregular-fields dosimetry program currently marketed...

journal_title：Medical physics

authors： Hallberg JR,Ibbott GS,Carson PL,Hendee WR

更新日期：1977-11-01 00:00:00

abstract：PURPOSE:The feasibility of magnetic resonance image (MRI)-based proton therapy is based, among several other factors, on the implementation of appropriate extensions on current dose calculation methods. This work aims to develop a pencil beam algorithm (PBA) for dose calculation of proton beams within magnetic field re...

journal_title：Medical physics

authors： Padilla-Cabal F,Georg D,Fuchs H

更新日期：2018-05-01 00:00:00

abstract：:A new calibration algorithm (GLAaS) to derive absolute dose maps from images acquired with the Varian PV-aS500 electronic portal imager (based on amorphous silicon detectors) has been developed incorporating the dependence of detector response on primary and transmitted radiation and on field size. Detector calibratio...

journal_title：Medical physics

authors： Nicolini G,Fogliata A,Vanetti E,Clivio A,Cozzi L

更新日期：2006-08-01 00:00:00

abstract：:To account for clinical divergent and polychromatic photon beams, we have developed kernel tilting and kernel hardening correction methods for convolution dose calculation algorithms. The new correction methods were validated by Monte Carlo simulation. The accuracy and computation time of the our kernel tilting and ke...

journal_title：Medical physics

authors： Liu HH,Mackie TR,McCullough EC

更新日期：1997-11-01 00:00:00

abstract：PURPOSE:To compare reconstructed volumes calculated via planimetry and frustum algorithms in the context of stepped transrectal ultrasound (US) imaging, and to estimate the reconstruction error for prostate volumes. METHODS:Prostate contours for 40 permanent implant patients were delineated on magnetic resonance (MR) ...

journal_title：Medical physics

authors： Liu D,Usmani N,Sloboda RS

更新日期：2013-03-01 00:00:00

abstract：PURPOSE:To develop an automated technique for evaluating lung stereotactic body radiotherapy (SBRT) plan quality and predicting achievable lung dose constraints. METHODS:We examined the workflow scripting capabilities of a radiation oncology software package (MIM Software Inc) for automatically generating mean dose gr...

journal_title：Medical physics

authors： Atwood T,Xing L,Hristov D

更新日期：2012-06-01 00:00:00

abstract：:A computerized scheme is being developed for the detection of masses in digital mammograms. Based on the deviation from the normal architectural symmetry of the right and left breasts, a bilateral subtraction technique is used to enhance the conspicuity of possible masses. The scheme employs two pairs of conventional ...

journal_title：Medical physics

authors： Yin FF,Giger ML,Doi K,Metz CE,Vyborny CJ,Schmidt RA

更新日期：1991-09-01 00:00:00

abstract：:It is well-known that the edge effect produced by phase contrast imaging results in the edge enhancement of x-ray images and thereby sharpens those images. It has recently been reported that phase contrast imaging using practical x-ray tubes with small focal spots has improved image sharpness as observed in the phase ...

journal_title：Medical physics

authors： Matsuo S,Katafuchi T,Tohyama K,Morishita J,Yamada K,Fujita H

更新日期：2005-08-01 00:00:00

abstract：PURPOSE:To add mathematical rigor to the merging phase of the recently published two-stage VMAT optimization method called VMERGE. Using an exact merging method, we are able to better characterize the tradeoff between delivery efficiency and dose quality. METHODS:VMERGE begins with an IMRT plan that uses 180 equi-spac...

journal_title：Medical physics

authors： Salari E,Craft D

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:X-ray fluorescence computer tomography (XFCT) is a new molecular imaging modality which uses x-ray excitation to stimulate the emission of fluorescent photons in high atomic number contrast agents. Scatter contamination is one of the main challenges in XFCT imaging which limits the molecular sensitivity. When p...

journal_title：Medical physics

authors： Vernekohl D,Tzoumas S,Zhao W,Xing L

更新日期：2018-05-25 00:00:00

abstract：PURPOSE:When designing a collimation system for pencil beam spot scanning proton therapy, a decision must be made whether or not to rotate, or focus, the collimator to match beamlet deflection as a function of off-axis distance. If the collimator is not focused, the beamlet shape and fluence will vary as a function of ...

journal_title：Medical physics

authors： Geoghegan TJ,Nelson NP,Flynn RT,Hill PM,Rana S,Hyer DE

更新日期：2020-07-01 00:00:00

abstract：PURPOSE:Currently, only iodine- and barium-based contrast media (CM) are used in clinical contrast-enhanced computed tomography (CE-CT). High-Z metals would produce a higher contrast at equal mass density for the x-ray spectra used in clinical CT. Using such materials might allow for significant dose reductions in CE-C...

journal_title：Medical physics

authors： Nowak T,Hupfer M,Brauweiler R,Eisa F,Kalender WA

更新日期：2011-12-01 00:00:00

abstract：PURPOSE:In using flat panel detectors (FPD) for cone beam computed tomography (CBCT), pixel gain variations may lead to structured nonuniformities in projections and ring artifacts in CBCT images. Such gain variations can be caused by change in detector entrance exposure levels or beam hardening, and they are not accou...

journal_title：Medical physics

authors： Altunbas C,Lai CJ,Zhong Y,Shaw CC

更新日期：2014-09-01 00:00:00

abstract：:We are investigating computerized methods to ultimately characterize bone trabecular pattern from clinical skeletal radiographs. In this paper, we present a "phantom" for potential use in the development and evaluation of computerized methods for characterizing radiographic trabecular patterns and ultimately bone stre...

journal_title：Medical physics

authors： Chinander MR,Giger ML,Martell JM,Jiang C,Favus MJ

更新日期：1999-11-01 00:00:00

abstract：PURPOSE:The authors discuss measurement methods and instrumentation useful for the characterization of the gray tracking performance of medical color monitors for diagnostic applications. The authors define gray tracking as the variability in the chromaticity of the gray levels in a color monitor. METHODS:The authors ...

journal_title：Medical physics

authors： Badano A,Wang J,Boynton P,Le Callet P,Cheng WC,Deroo D,Flynn MJ,Matsui T,Penczek J,Revie C,Samei E,Steven PM,Swiderski S,Van Hoey G,Yamaguchi M,Hasegawa M,Nagy BV

更新日期：2016-07-01 00:00:00

abstract：:Respiratory motion can introduce significant errors in radiotherapy. Conventional CT scans as commonly used for treatment planning can include severe motion artifacts that result from interplay effects between the advancing scan plane and object motion. To explicitly include organ/target motion in treatment planning a...

journal_title：Medical physics

authors： Rietzel E,Pan T,Chen GT

更新日期：2005-04-01 00:00:00