Poster - Thurs Eve-10: The accuracy of MU calculations for enhanced dynamic wedge with the Varian's anisotropic analytical algorithm.

abstract：PURPOSE:Two types of tumor hypoxia most likely exist in human cancers: Chronic hypoxia due to the paucity of blood capillaries and acute hypoxia due to temporary shutdoWn of microvasculatures or fluctuation in the red cell flux. In a recent hypoxia imaging study using 18F-FMISO PET, the authors observed variation in tr...

journal_title：Medical physics

authors： Wang K,Yorke E,Nehmeh SA,Humm JL,Ling CC

更新日期：2009-10-01 00:00:00

abstract：:Respiration can cause tumors in the thorax or abdomen to move by as much as 3 cm; this movement can adversely affect the planning and delivery of radiation treatment. Several techniques have been used to compensate for respiratory motion, but all have shortcomings. Manufacturers of computed tomography (CT) equipment h...

journal_title：Medical physics

authors： Fitzpatrick MJ,Starkschall G,Antolak JA,Fu J,Shukla H,Keall PJ,Klahr P,Mohan R

更新日期：2006-01-01 00:00:00

abstract：PURPOSE:A multi-institutional planning study was performed to evaluate the frequency that current guidelines established by Radiation Therapy Oncology Group (RTOG) protocols and other literature for lung stereotactic body radiotherapy (SBRT) treatments are followed. METHODS:A total of 300 patients receiving lung SBRT ...

journal_title：Medical physics

authors： Woerner A,Roeske JC,Harkenrider MM,Fan J,Aydogan B,Koshy M,Laureckas R,Vali F,Campana M,Surucu M

更新日期：2015-08-01 00:00:00

abstract：:In order to determine accurately the relative x-ray intensities transmitted through the different steps of an aluminum stepwedge and incident on an image intensifier (II)-TV digital system, we used a 100-mm camera which was attached to the II output. The characteristic curves of an II-TV digital system, which relate t...

journal_title：Medical physics

authors： Fujita H,Doi K

更新日期：1986-11-01 00:00:00

abstract：:The determination of the radiation exposure history of the population has become increasingly important in the study of the effects of low-level radiation. The present work was started to try to obtain an in vivo dosimeter that could give an indication of radiation exposure. Dental enamel is the only living tissue whi...

journal_title：Medical physics

authors： Pass B,Aldrich JE

更新日期：1985-05-01 00:00:00

abstract：PURPOSE:The liver segments divided by Couinaud classification method are used to understand the functional anatomy of liver, which is significant in hepatic resection surgery. In Couinaud classification method, each third-order branch of the portal vein (PV) defines the supplied territory of a corresponding liver segme...

journal_title：Medical physics

authors： Wu C,Fu T,Gao Y,Liu Y,Fan J,Ai D,Song H,Yang J

更新日期：2021-02-02 00:00:00

abstract：:A filtered backprojection algorithm is developed for single photon emission computed tomography (SPECT) imaging with an astigmatic collimator having a displaced center of rotation. The astigmatic collimator has two perpendicular focal lines, one that is parallel to the axis of rotation of the gamma camera and one that...

journal_title：Medical physics

authors： Wang H,Smith MF,Stone CD,Jaszczak RJ

更新日期：1998-08-01 00:00:00

abstract：PURPOSE:The recent introduction of digital tomosynthesis imaging into routine clinical use has enabled the acquisition of volumetric patient data within a standard radiographic examination. Tomosynthesis requires the acquisition of multiple projection views, requiring additional dose compared to a standard projection e...

journal_title：Medical physics

authors： Sabol JM

更新日期：2009-12-01 00:00:00

abstract：PURPOSE:High-dose-rate brachytherapy (HDR-BT) is a treatment option for malignant skin diseases compared to external beam radiation therapy, HDR-BT provides improved target coverage, better organ sparing, and has comparable treatment times. This is especially true for large clinical targets with complex topologies. To ...

journal_title：Medical physics

authors： Guthier CV,Devlin PM,Harris TC,O'Farrell DA,Cormack RA,Buzurovic I

更新日期：2020-03-01 00:00:00

abstract：PURPOSE:The purpose of this work is twofold: First, to characterize the artifacts occurring in helical 4D-CT imaging; second, to propose a method that can automatically identify the artifacts in 4D-CT images. The authors have designed a process that can automatically identify the artifacts in 4D-CT images, which may be...

journal_title：Medical physics

authors： Han D,Bayouth J,Bhatia S,Sonka M,Wu X

更新日期：2011-04-01 00:00:00

abstract：:Computed tomography is sensitive to changes in the imaged distribution during acquisition of the projection data. Previous investigations have emphasized discrete or discontinuous changes in the imaged object. Recent advances have motivated our investigation of object time-dependence characterized by a continuous func...

journal_title：Medical physics

authors： Holden JE,Ip WR

更新日期：1978-11-01 00:00:00

abstract：PURPOSE:The purpose of this work was to assess the inherent image quality characteristics of a new multidetector computed tomography system in terms of noise, resolution, and detectability index as a function of image acquisition and reconstruction for a range of clinically relevant settings. METHODS:A multisized imag...

journal_title：Medical physics

authors： Solomon J,Wilson J,Samei E

更新日期：2015-08-01 00:00:00

abstract：:Depending on the clinical application, it is frequently necessary to tilt the gantry of an x-ray CT system with respect to the patient and couch. For single-slice fan-beam systems, tilting the gantry introduces no errors or artifacts. Most current systems, however, are helical multislice systems with up to 16 slices. ...

journal_title：Medical physics

authors： Hein I,Taguchi K,Silver MD,Kazama M,Mori I

更新日期：2003-12-01 00:00:00

abstract：PURPOSE:As the predominant driver of respiratory motion, the diaphragm represents a key surrogate for motion management during the irradiation of thoracic cancers. Existing approaches to diaphragm tracking often produce phase-based estimates, suffer from lateral side failures or are not executable in real-time. In this...

journal_title：Medical physics

authors： Hindley N,Keall P,Booth J,Shieh CC

更新日期：2019-10-01 00:00:00

abstract：PURPOSE:Although robot-assisted coronary artery bypass grafting (RA-CABG) has gained more acceptance worldwide, its success still depends on the surgeon's experience and expertise, and the conversion rate to full sternotomy is in the order of 15%-25%. One of the reasons for conversion is poor pre-operative planning, wh...

journal_title：Medical physics

authors： Cho DS,Linte C,Chen EC,Bainbridge D,Wedlake C,Moore J,Barron J,Patel R,Peters T

更新日期：2012-03-01 00:00:00

abstract：PURPOSE:To correlate the Cole relaxation frequencies obtained from measurements of the electrical properties of breast tissue to the presence or absence of cancer. METHODS:Four-lead impedance measurements were obtained on ex vivo specimens extracted during surgery from 187 volunteer patients. Data were acquired with a...

journal_title：Medical physics

authors： Gregory WD,Marx JJ,Gregory CW,Mikkelson WM,Tjoe JA,Shell J

更新日期：2012-07-01 00:00:00

abstract：PURPOSE:The harmonic spectrum of magnetic nanoparticles contains valuable information about the quantity and environment of the particles. Harmonic amplitudes have been used to produce quantitative images and ratios of these amplitudes have been used to monitor changes in the particle environment. Harmonic phase angles...

journal_title：Medical physics

authors： Rauwerdink AM,Weaver JB

更新日期：2010-06-01 00:00:00

abstract：:We have previously investigated a method of high-energy x-ray spectral reconstruction from transmission data by direct resolution of a matrix system. This technique uses the spectral vectorial algebra formalism. The resolution has previously been tested on a 12 MV photon beam. To extend and to test the validity of the...

journal_title：Medical physics

authors： Francois P,Coste F,Bonnet J,Caselles O

更新日期：1997-05-01 00:00:00

abstract：PURPOSE:Plastic scintillation detectors are used for dosimetry in small radiation fields with high dose gradients, e.g., provided by β-emitting sources like 106 Ru/106 Rh eye plaques. A drawback is a background signal caused by Cerenkov radiation generated by electrons passing the optical fibers (light guides) of this ...

journal_title：Medical physics

authors： Eichmann M,Thomann B

更新日期：2017-09-01 00:00:00

abstract：:Magnetic resonance images can be compromised by constant frequency (CF) noise, such as radio frequency (RF) noise. We investigate the effects of CF noise in four imaging methods with non-uniform k-space sampling: single-shot echo-planar imaging (EPI) with sinusoidal readout gradients, phase-encoded echo-planar spectro...

journal_title：Medical physics

authors： Du W,Karczmar GS,Pan X

更新日期：2002-08-01 00:00:00

abstract：:The image artifacts characteristic of a scanning chest radiographic system are reviewed. The technique employs a pulsed beam of radiation swept in an overlapping raster pattern that can result in severe ripple and scan line artifacts with improper scanning parameters. A one-dimensional treatment of the scanner geometr...

journal_title：Medical physics

authors： Plewes DB,Vogelstein E

更新日期：1984-03-01 00:00:00

abstract：:Computer-aided diagnostic (CAD) schemes have been developed to assist radiologists in the early detection of lung cancer in radiographs and computed tomography (CT) images. In order to improve sensitivity for nodule detection, many researchers have employed a filter as a preprocessing step for enhancement of nodules. ...

journal_title：Medical physics

authors： Li Q,Sone S,Doi K

更新日期：2003-08-01 00:00:00

abstract：:Monte Carlo (MC) techniques can be used to build a simulation model of an electron accelerator to calculate output factors for electron fields. This can be useful during commissioning of electron beams from a linac and in clinical practice where irregular fields are also encountered. The Monte Carlo code BEAM/EGS4 was...

journal_title：Medical physics

authors： Verhaegen F,Mubata C,Pettingell J,Bidmead AM,Rosenberg I,Mockridge D,Nahum AE

更新日期：2001-06-01 00:00:00

abstract：PURPOSE:Image guidance is crucial for percutaneous tumor ablations, enabling accurate needle-like applicator placement into target tumors while avoiding tissues that are sensitive to injury and/or correcting needle deflection. Although ultrasound (US) is widely used for image guidance, magnetic resonance (MR) is prefer...

journal_title：Medical physics

authors： Yamada A,Tokuda J,Naka S,Murakami K,Tani T,Morikawa S

更新日期：2020-03-01 00:00:00

abstract：PURPOSE:The quality of a treatment plan for stereotactic body radiotherapy (SBRT) depends on an experience of each treatment planner. Therefore, the treatment plans are subjectively determined by comparison of several treatment plans developed by time consuming iterative manners, while considering the benefit to a tumo...

journal_title：Medical physics

authors： Magome T,Arimura H,Shioyama Y,Mizoguchi A,Tokunaga C,Nakamura K,Honda H,Ohki M,Toyofuku F,Hirata H

更新日期：2012-06-01 00:00:00

abstract：:An easy-to-use phantom has been constructed for checking the accuracy of a stereotactic computed tomography localization system. This phantom has been used on a commercially available stereotactic radiosurgery system. With this system, the phantom reference point, whose location is established by means of a precision ...

journal_title：Medical physics

authors： Ekstrand KE,Olds WW,Branch CL

更新日期：1993-03-01 00:00:00

abstract：:Tumor cells can be killed by heating to 42.5 degrees C. It is convenient to localize heating by passing electric current at 500 kHz through tissue between a pair of electrodes. It is desirable to determine, for a given electrode-tissue configuration, what the resulting field and, therefore, current distribution will b...

journal_title：Medical physics

authors： Hutson RL

更新日期：1976-07-01 00:00:00

abstract：:A systems analysis of reduced dose mammography with scatter removal has quantitatively specified the relationships between the several parameters in mammography systems. While the results are only preliminary in the sense that they need to be proven experimentally, they do seem to provide a good feel for the nature of...

journal_title：Medical physics

authors： Muntz EP

更新日期：1979-03-01 00:00:00

abstract：:We attempt to select an optimal value of regularization parameter in the optimization problems for intensity-modulated radiotherapy which are solved using a variational regularization technique. We apply to inverse treatment planning the L-curve method which was developed to determine the regularization parameter in t...

journal_title：Medical physics

authors： Chvetsov AV

更新日期：2005-08-01 00:00:00

abstract：:We have made a comparative investigation of the estimated spectra obtained by the Laplace transform analysis of the transmitted exposure data measured in an absorption study of a 4-MV x-ray beam. Four transform pair models currently used with this method have been evaluated. It has been determined that the Archer-Wagn...

journal_title：Medical physics

authors： Ahuja SD,Steward PG,Roy TS,Slessinger ED

更新日期：1986-05-01 00:00:00