Comparison of clinical and physical measures of image quality in chest and pelvis computed radiography at different tube voltages

Journal Article · Wed Nov 15 04:00:00 EST 2006 · Medical Physics

DOI:https://doi.org/10.1118/1.2362871· OSTI ID:20853703

Sandborg, Michael; Tingberg, Anders; Ullman, Gustaf; Dance, David R; Alm Carlsson, Gudrun ^[1]

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1. Department of Radiation Physics, Faculty of Health Sciences, Linkoeping University, SE-581 85 Linkoeping (Sweden)

The aim of this work was to study the dependence of image quality in digital chest and pelvis radiography on tube voltage, and to explore correlations between clinical and physical measures of image quality. The effect on image quality of tube voltage in these two examinations was assessed using two methods. The first method relies on radiologists' observations of images of an anthropomorphic phantom, and the second method was based on computer modeling of the imaging system using an anthropomorphic voxel phantom. The tube voltage was varied within a broad range (50-150 kV), including those values typically used with screen-film radiography. The tube charge was altered so that the same effective dose was achieved for each projection. Two x-ray units were employed using a computed radiography (CR) image detector with standard tube filtration and antiscatter device. Clinical image quality was assessed by a group of radiologists using a visual grading analysis (VGA) technique based on the revised CEC image criteria. Physical image quality was derived from a Monte Carlo computer model in terms of the signal-to-noise ratio, SNR, of anatomical structures corresponding to the image criteria. Both the VGAS (visual grading analysis score) and SNR decrease with increasing tube voltage in both chest PA and pelvis AP examinations, indicating superior performance if lower tube voltages are employed. Hence, a positive correlation between clinical and physical measures of image quality was found. The pros and cons of using lower tube voltages with CR digital radiography than typically used in analog screen-film radiography are discussed, as well as the relevance of using VGAS and quantum-noise SNR as measures of image quality in pelvis and chest radiography.

• OSTI ID: 20853703
• Journal Information: Medical Physics, Journal Name: Medical Physics Journal Issue: 11 Vol. 33; ISSN 0094-2405; ISSN MPHYA6
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
CHEST
COMPUTERIZED TOMOGRAPHY
CORRELATIONS
DOSIMETRY
ELECTRIC POTENTIAL
IMAGE PROCESSING
IMAGES
MONTE CARLO METHOD
PELVIS
PHANTOMS
SIGNAL-TO-NOISE RATIO
X RADIATION