Technical note: a fast laser-based optical-CT scanner for three-dimensional radiation dosimetry.

abstract：:Nuclear Magnetic Resonance (NMR) permits the noninvasive measurement of blood flow signals unimpaired by clothes, bandages, casts, etc. The cylindrical crossed-coil NMR blood flowmeter was used to measure blood flow through a cross-section of the human forearm. Two calibration procedures are described: one for pulsati...

journal_title：Medical physics

authors： Salles-Cunha SX,Halbach RE,Battocletti JH,Sances A Jr

更新日期：1981-07-01 00:00:00

abstract：:In this paper, we present a unified framework to reconstruct images for both fan beam and cone beam projections. The important feature of our theoretical framework is that it does not depend on the classical concept of the Radon transform at all. This property allows us to directly generalize the ideas and techniques ...

journal_title：Medical physics

authors： Chen GH

更新日期：2003-06-01 00:00:00

abstract：:The authors describe a method for directly digitizing optical images with a photostimulable phosphor (PSP) system. A PSP plate is initially charged with an exposure to a uniform x-ray field, and is then exposed to an optical image which discharges the plate in relation to the amount of incident light. Two applications...

journal_title：Medical physics

authors： Dobbins JT 3rd,Chotas HG,Benveniste H

更新日期：1992-07-01 00:00:00

abstract：:The purpose of this study is to incorporate the dosimetric effect of random patient positioning uncertainties directly into a commercial treatment planning system's IMRT plan optimization algorithm through probabilistic treatment planning (PTP) and compare coverage of this method with margin-based planning. In this wo...

journal_title：Medical physics

authors： Moore JA,Gordon JJ,Anscher MS,Siebers JV

更新日期：2009-09-01 00:00:00

abstract：PURPOSE:This article introduces the use of low power continuous wave frequency modulated radar for medical applications, specifically for remote monitoring of vital signs in patients. METHODS:Gigahertz frequency radar measures the electromagnetic wave signal reflected from the surface of a human body and from tissue b...

journal_title：Medical physics

authors： Mostov K,Liptsen E,Boutchko R

更新日期：2010-03-01 00:00:00

abstract：:In computer simulations of x-ray CT systems one can either use continuous geometrical descriptions for phantoms or a voxelized representation. The voxelized approach allows arbitrary phantoms to be defined without being confined to geometrical shapes. The disadvantage of the voxelized approach is that inherent errors ...

journal_title：Medical physics

authors： Goertzen AL,Beekman FJ,Cherry SR

更新日期：2002-04-01 00:00:00

abstract：:Anatomy-based positron emission tomography (PET) image enhancement techniques have been shown to have the potential for improving PET image quality. However, these techniques assume an accurate alignment between the anatomical and the functional images, which is not always valid when imaging the chest due to respirato...

journal_title：Medical physics

authors： Qiao F,Pan T,Clark JW Jr,Mawlawi O

更新日期：2007-12-01 00:00:00

abstract：PURPOSE:To apply the recent code of practice from the IAEA/AAPM, TRS 483, to helical tomotherapy (HT) for reference and relative dosimetry obtaining correction factors for the Exradin A1SL ionization chamber. METHODS:The beam quality correction factor for the A1SL chamber was obtained through three different approache...

journal_title：Medical physics

authors： Lopes MDC,Santos T,Ventura T,Capela M

更新日期：2019-12-01 00:00:00

abstract：:Ultrasound-induced blood stasis has been observed for more than 30 years. Most of the literature has been focused on the health risks associated with this phenomenon and methods employed to prevent stasis from occurring during ultrasound imaging. To date, experimental observations have been either in vitro or invasive...

journal_title：Medical physics

authors： Winey BA,Misic V,Liao L,Parker K,Fenton BM,Yu Y

更新日期：2006-06-01 00:00:00

abstract：:The relative sensitivity of the half-value layer (HVL) method as a quality index for megavoltage x-ray beams is examined by theoretical calculation and experimental measurements for 4-, 6-, 10-, and 25-MV x-ray beams. It is shown that lower atomic number materials are more sensitive to beam quality changes than higher...

journal_title：Medical physics

authors： Meli JA,Nath R

更新日期：1985-01-01 00:00:00

abstract：:Because of the high energy of the treatment beam, contrast of portal verification films is very poor. A simple contrast enhancement technique is described which we have labeled selective histogram equalization (SHE), to improve visualization of double-exposure portal images and this facilitate the beam verification pr...

journal_title：Medical physics

authors： Crooks I,Fallone BG

更新日期：1993-01-01 00:00:00

abstract：:Stereotactic Body Radiation Therapy (SBRT) is an important form of cancer therapy with increasingly broad application across a spectrum of tumor types in primary and metastatic settings. In this presentation the radiation biology, clinical experience from various trials, and cautionary updates on normal tissue toleran...

journal_title：Medical physics

authors： Read P

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:A number of techniques are available to determine the dosimetric impact of intrafraction motion during intensity modulated radiation therapy (IMRT). Motion-induced dose perturbations can be determined both computationally and experimentally using a number of different dosimetric metrics. However, these measures...

journal_title：Medical physics

authors： Waghorn BJ,Meeks SL,Langen KM

更新日期：2011-08-01 00:00:00

abstract：PURPOSE:Tumor motion during radiotherapy can cause a reduction in target dose coverage and an increase in healthy tissue exposure. Tumor motion is not strictly translational and often exhibits complex six degree-of-freedom (6DoF) translational and rotational motion. Although the dosimetric impact of prostate tumor tran...

journal_title：Medical physics

authors： Shi K,Dipuglia A,Booth J,Alnaghy S,Kyme A,Keall P,Nguyen DT

更新日期：2020-12-01 00:00:00

abstract：:Pixel size is of great interest in the flat-panel detector design because of its potential impact on image quality. In the particular case of angiographic x-ray fluoroscopy, small pixels are required in order to adequately visualize interventional devices such as guidewires and stents which have wire diameters as smal...

journal_title：Medical physics

authors： Jiang Y,Wilson DL

更新日期：2006-03-01 00:00:00

abstract：PURPOSE:Recent recommendations of the International Commission on Radiological Protection state that the use of effective dose (E) for assessing patient exposure has severe limitations, though it can be kept for dose comparisons. In cardiology procedures, the equivalent dose (H(T)) is one of the most appropriate dose q...

journal_title：Medical physics

authors： Compagnone G,Ortolani P,Domenichelli S,Ovi V,Califano G,Dall'Ara G,Marzocchi A

更新日期：2011-04-01 00:00:00

abstract：PURPOSE:To determine the accuracy of VMAT treatment planning and delivery for patients undergoing radiotherapy in the head and neck. METHOD AND MATERIALS:A dosimetric study of a typical head and neck treatment plan has been carried out using Chamber, film and TLD's placed inside an anthropomorphic phantom. Lateral and...

journal_title：Medical physics

authors： Aldaais E,Tedeschi D,Gebreamlak W,Shieder T,Alkhatib H

更新日期：2012-06-01 00:00:00

abstract：:A computer program was implemented to predict mammography x-ray beam parameters in the range 20-40 kV for Mo/Mo, Mo/Rh, Rh/Rh, and W/Al target/filter combinations. The computation method used to simulate mammography x-ray spectra is based on the Boone et al. model. The beam quality parameters such as the half-value la...

journal_title：Medical physics

authors： Kharrati H,Zarrad B

更新日期：2003-10-01 00:00:00

abstract：PURPOSE:Over the last four decades, Ocular Proton Therapy has been successfully used to treat patients affected by intraocular lesions. For this, treatment geometry verification is routinely performed using radiographic images to align a configuration of fiducial radiopaque markers implanted on the sclera outer surface...

journal_title：Medical physics

authors： Via R,Hennings F,Fattori G,Fassi A,Pica A,Lomax A,Weber DC,Baroni G,Hrbacek J

更新日期：2018-05-01 00:00:00

abstract：:Three-dimensional water phantoms are routinely used when acquiring the data necessary to commission medical linear accelerators. A new water phantom controller has been developed at our institution that is unique in several aspects. The water phantom controller is based on an IBM XT compatible computer. This has been ...

journal_title：Medical physics

authors： Schmid MG,Morris RL

更新日期：1989-01-01 00:00:00

abstract：:The resolution has been evaluated for an experimental x-ray image intensifier employing three microchannel plates (MCPs) as the photon absorber and electron multipliers. The line spread function (LSF) was measured and used for determination of the modulation transfer function (MTF). The MTF was found to be independent...

journal_title：Medical physics

authors： Gould RG

更新日期：1978-01-01 00:00:00

abstract：:In addition to the familiar problems of reduced contrast and signal-to-noise ratio (SNR) in the single energy case, dual-energy subtractions in the presence of scattered radiation suffer further degradations from: (1) artifacts due to nonuniform subtraction of scatter, and (2) a serious deterioration of the signal of ...

journal_title：Medical physics

authors： Wagner FC,Macovski A,Nishimura DG

更新日期：1988-09-01 00:00:00

abstract：:The immediate goal of clinically based x-ray-transmission computed tomography (CT) is to provide a measurement of the x-ray linear attenuation coefficient in cross section with the ultimate goal of impacting on patient management and care. To do this with the accuracy needed for clinical goals requires the careful int...

journal_title：Medical physics

authors： McCullough EC,Payne JT

更新日期：1977-03-01 00:00:00

abstract：:A single-field rotational total skin electron irradiation technique has recently been developed at the McGill University for treatment of skin malignancies. The dose received by a given surface point during rotation in a uniform large electron field depends on the radius of rotation of the surface point, on the local ...

journal_title：Medical physics

authors： Pla C,Heese R,Pla M,Podgorsak EB

更新日期：1984-07-01 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：:Complementary metal-oxide-semiconductors (CMOS) active pixel sensors can be optically coupled to CsI:Tl phosphors forming a indirect active pixel flat panel imager (APFPI) for high performance medical imaging. The aim of this work is to determine the x-ray imaging capabilities of CMOS-based APFPI and study the signal ...

journal_title：Medical physics

authors： Arvanitis CD,Bohndiek SE,Blakesley J,Olivo A,Speller RD

更新日期：2009-01-01 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：:The relatively precise placement of brachytherapy sources afforded by stereotactic frames for brain implants is not generally achievable for other sites, which lack the fixed geometry of the cranium and its contents. An exception is a source-containing rigid mold that delivers brachytherapy when inserted securely in a...

journal_title：Medical physics

authors： Anderson LL,Zlotolow IM,McCormick B,Harrison LB

更新日期：1995-03-01 00:00:00

abstract：PURPOSE:Ablative hyperthermia (>55 °C) has been used as a definitive treatment for accessible solid tumors not amenable to surgery, whereas mild hyperthermia (40-45 °C) has been shown effective as an adjuvant for both radiotherapy and chemotherapy. An optimal mild hyperthermia treatment is spatially accurate, with prec...

journal_title：Medical physics

authors： Partanen A,Tillander M,Yarmolenko PS,Wood BJ,Dreher MR,Kohler MO

更新日期：2013-01-01 00:00:00

abstract：:Because of complex dose distributions and dose gradients that are created in three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiation therapy (IMRT), photon- and electron-energy spectra might change significantly with spatial locations and doses. This study examined variations in photon- and...

journal_title：Medical physics

authors： Jang SY,Liu HH,Mohan R,Siebers JV

更新日期：2007-04-01 00:00:00