Abstract
We established a method for image-based diagnosis of cerebral stroke by
developing a phantom that could visualize cerebral stroke using X-ray CT imaging, while
evaluating the imaging conditions. We recently improved the contrast of acute-stage cerebral
infarction using virtual monochromatic images obtained by Dual-Energy CT. We measured
radiation doses using the newly developed phantom while assessing its potential clinical
application. In this study, the tube voltages with a thin（ Sn） filter were 80 kV / Sn 140 kV, 100
kV / Sn 140 kV, and 140 kV / 80 kV ; the tube current time products were 400, 600, and 800
mAs ; and the scanning range was 120 mm from the orbitomeatal line to the parietal region.
The dose was measured three times using TLD, and the absorbed dose was obtained from
the average. Compared with 120 kV, the absorbed dose could be reduced by approximately
47 ％ at 80 kV / Sn 140 kV, approximately 30 ％ at 100 kV / Sn 140 kV, and approximately
22 ％ at 140 kV / 80 kV, when the tube current time product was 600 mAs. Our dose
measurement for visualizing acute-stage cerebral infarction revealed that the dose could be
reduced with Dual-Energy CT compared with CT at 120 kV.
