The Experts below are selected from a list of 183 Experts worldwide ranked by ideXlab platform

C J Kotre - One of the best experts on this subject based on the ideXlab platform.

  • receptor dose in digital Fluorography a comparison between theory and practice
    Physics in Medicine and Biology, 2001
    Co-Authors: N W Marshall, C J Kotre, K J Robson, A R Lecomber
    Abstract:

    A method of identifying the dose per image when quantum mottle no longer dominates the image statistics is presented as a first step towards quantitative optimization in native and subtracted digital Fluorography. The method is based on measurements of threshold contrast over a range of receptor doses and the application of a simple model of the threshold contrast detection task to estimate the magnitude of system noise sources. The point at which system and quantum noise sources are equal in magnitude is proposed as the practical upper limit for dose per image. The method is applied to a typical digital Fluorography system and the results are placed into the context of the range of dose per image values found from a regional survey of digital Fluorography units. While there is broad agreement between the dose per image values in the survey with values predicted from the experimental method, the considerable spread in survey doses suggests there are instances where the use of a high dose per image is unjustified.

  • A micro-computer based CT and digital Fluorography system for radiotherapy simulators.
    Radiotherapy and Oncology, 1993
    Co-Authors: C J Kotre, R.m. Harrison
    Abstract:

    Abstract A low cost system designed to produce low resolution CT images from a radiotherapy treatment simulator is described. The system is based upon a standard micro-computer and operates using the simulator's image intensifier as the CT detector. The resulting images are intended to supply cross-sectional anatomical information appropriate for the application of inhomogeneity corrections to treatment plans for megavoltage radiotherapy of the thorax. Options for digital Fluorography and hold last-frame fluoroscopy are also described. Examples of clinical images are presented.

A R Lecomber - One of the best experts on this subject based on the ideXlab platform.

  • receptor dose in digital Fluorography a comparison between theory and practice
    Physics in Medicine and Biology, 2001
    Co-Authors: N W Marshall, C J Kotre, K J Robson, A R Lecomber
    Abstract:

    A method of identifying the dose per image when quantum mottle no longer dominates the image statistics is presented as a first step towards quantitative optimization in native and subtracted digital Fluorography. The method is based on measurements of threshold contrast over a range of receptor doses and the application of a simple model of the threshold contrast detection task to estimate the magnitude of system noise sources. The point at which system and quantum noise sources are equal in magnitude is proposed as the practical upper limit for dose per image. The method is applied to a typical digital Fluorography system and the results are placed into the context of the range of dose per image values found from a regional survey of digital Fluorography units. While there is broad agreement between the dose per image values in the survey with values predicted from the experimental method, the considerable spread in survey doses suggests there are instances where the use of a high dose per image is unjustified.

John Coppola - One of the best experts on this subject based on the ideXlab platform.

  • effectiveness of Fluorography versus cineangiography at reducing radiation exposure during diagnostic coronary angiography
    American Journal of Cardiology, 2014
    Co-Authors: Binita Shah, Lakshmi Tummala, Frederick Feit, Michael Liou, Michael J Attubato, Chad Kliger, Steven P Sedlis, Louis H Miller, Sripal Bangalore, John Coppola
    Abstract:

    Coronary angiography is the gold standard for defining obstructive coronary disease. However, radiation exposure remains an unwanted hazard. Patients referred for coronary angiography with abdominal circumference 60 ml/min were randomized to the Fluorography (n = 25) or cineangiography (n = 25) group. Patients in the Fluorography group underwent coronary angiography using retrospectively stored Fluorography with repeat injection under cineangiography only when needed for better resolution per operator's discretion. Patients in the cineangiography group underwent coronary angiography using routine cineangiography. The primary end point was patient radiation exposure measured by radiochromic film. Secondary end points included the radiation output measurement of kerma-area product and air kerma at the interventional reference point (Ka,r) and operator radiation exposure measured by a dosimeter. Patient radiation exposure (158.2 mGy [76.5 to 210.2] vs 272.5 mGy [163.3 to 314.0], p = 0.001), kerma-area product (1,323 μGy·m 2 [826 to 1,765] vs 3,451 μGy·m 2 [2,464 to 4,818], p

R.m. Harrison - One of the best experts on this subject based on the ideXlab platform.

  • A micro-computer based CT and digital Fluorography system for radiotherapy simulators.
    Radiotherapy and Oncology, 1993
    Co-Authors: C J Kotre, R.m. Harrison
    Abstract:

    Abstract A low cost system designed to produce low resolution CT images from a radiotherapy treatment simulator is described. The system is based upon a standard micro-computer and operates using the simulator's image intensifier as the CT detector. The resulting images are intended to supply cross-sectional anatomical information appropriate for the application of inhomogeneity corrections to treatment plans for megavoltage radiotherapy of the thorax. Options for digital Fluorography and hold last-frame fluoroscopy are also described. Examples of clinical images are presented.

A R Cowen - One of the best experts on this subject based on the ideXlab platform.

  • digital cardiac imaging the death knell of cineangiography
    British Journal of Radiology, 1992
    Co-Authors: John F Dyet, W Hartley, A R Cowen, C P Aber
    Abstract:

    Digital X-ray imaging techniques have achieved wide-spread acclaim in general vascular diagnosis and in the support of interventional procedures. However, in cardiac angiography, acceptability of digital imaging until recently, has been less enthusiastic. To a large extent this has reflected the effectiveness of cine Fluorography and the exacting performance standards that it sets to any competing technique. Whereas cine Fluorography provides rapid acquisition of dynamic sequences of high (spatio-temporal) fidelty images, the review of these images has to be retrospective and in practice it is necessary to rely heavily on the modest image quality provided by TV fluoroscopy for the on-line evaluation of the procedure. Early attempts at digital cardiac imaging based upon digital subtraction angiography (DSA) produced results of widely inconsistent quality. This was partly because of the inferior specification of the equipment used at that time. In addition, however, the dynamic nature of the heart itself se...

  • a physical image quality evaluation of a digital spot Fluorography system
    Physics in Medicine and Biology, 1992
    Co-Authors: A R Cowen, A Workman
    Abstract:

    A physical evaluation of the imaging performance of the first digital spot Fluorography system installed in the UK is presented. Measurements have been made of dynamic range, unsharpness (MTF), noise (Wiener spectrum) and threshold contrast detail detectability (TCDD) and the results compared with those produced by conventional spot-film radiography systems. Noise-equivalent parameters are derived from the objective measurements and the results related to the findings of the TCDD tests.