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Further Reduction of Radiation Dose in Helical CT for Lung Cancer Screening Using Small Tube Current and a Newly Designed Filter

Authors :
Itoh, Shigeki
Koyama, Shuji
Ikeda, Mituru
Ozaki, Masahiro
Sawaki, Akiko
Iwano, Shingo
Ishigaki, Takeo
Source :
Journal of Thoracic Imaging; April 2001, Vol. 16 Issue: 2 p81-88, 8p
Publication Year :
2001

Abstract

A new aluminum filter, 5.8 mm thick at the center, was designed. The effective energy, exposure dose, absorbed dose, and noise were measured by using low-dose technique, very low-dose technique with a conventional filter, and very low-dose technique with a new filter on a chest phantom. Accuracy of very low-dose computed tomography (CT) with a new filter was compared against standard helical CT in 40 patients and against chest radiography in 35 patients. Effective energies were 42.6 keV and 51.6 keV at a conventional filter and the new filter, respectively. Compared against 20mA with a conventional filter, exposure dose was reduced by 17, and absorbed dose was equivalent, at 30 mA with the new filter. Noise was improved by 9. Compared with standard helical CT, the sensitivity, specificity, and accuracy of very-low-dose helical CT were 100, 88, and 95, respectively. Very-low-dose helical CT was found to be significantly superior to chest radiography in the detection of lung cancers. Using a smaller tube current and an appropriate filter allows a further reduction in radiation dose in helical CT for lung cancer screening.

Details

Language :
English
ISSN :
08835993 and 15360237
Volume :
16
Issue :
2
Database :
Supplemental Index
Journal :
Journal of Thoracic Imaging
Publication Type :
Periodical
Accession number :
ejs49709030