Anders Tingberg
Associate professor
Comparison of clinical and physical measures of image quality in chest and pelvis computed radiography at different tube voltages
Author
Summary, in English
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.
Department/s
- Medical Radiation Physics, Malmö
Publishing year
2006
Language
English
Pages
4169-4175
Publication/Series
Medical Physics
Volume
33
Issue
11
Document type
Journal article
Publisher
American Association of Physicists in Medicine
Topic
- Biophysics
Keywords
- chest radiography
- signal-to-noise ratio
- visual grading analysis
- tube voltage
- image quality
- effective dose
- pelvis radiography
- computed
- radiography
Status
Published
Research group
- Medical Radiation Physics, Malmö
ISBN/ISSN/Other
- ISSN: 0094-2405