Open AccessInfluence of exposure parameters on patient dose and image noise in computed tomography
Author(s) -
D. Stoyanov,
J. Vassileva
Publication year - 2009
Publication title -
polish journal of medical physics and engineering
Language(s) - English
Resource type - Journals
eISSN - 1898-0309
pISSN - 1425-4689
DOI - 10.2478/v10013-009-0021-9
Subject(s) - imaging phantom , pencil (optics) , image noise , image quality , computed tomography , noise (video) , nuclear medicine , tomography , hounsfield scale , ionization chamber , automatic exposure control , medical physics , medicine , computer science , materials science , radiology , artificial intelligence , image (mathematics) , physics , optics , ionization , ion , quantum mechanics
Influence of exposure parameters on patient dose and image noise in computed tomography This work presents the results of investigation of influence of main exposure parameters on the patient dose and image noise on five clinical computed tomography units. Patient dose was determined by means of the quantity CTDI air free on air measured with pencil shaped ionization chamber. The image noise was estimated as a standard deviation of CT numbers in a 500 mm 2 central region of interest in a water-equivalent phantom positioned in the centre of rotation. The alteration of tube voltage and tube current show the potential in patient dose reduction up to 40% but may deteriorate image quality and has to be carefully applied in order to optimize the clinical CT protocols taking into account the specific clinical task. This survey is essential for optimization of routine CT protocols especially for CT units without automatic exposure control systems, which are main part of CT units in Bulgaria.