Whole-body CT with high heat-capacity X-ray tube and automated tube current modulation--effect of tube current limitation on contrast enhancement, image quality and radiation dose.
OBJECTIVE
To evaluate the effect of tube current limitation on contrast enhancement, image quality, and radiation dose in whole-body 64-detector CT with a high heat-capacity X-ray tube and automated tube current modulation.


METHODS
One hundred eighteen patients were randomized into three whole-body CT protocols: tube current limitation at 210 mA, 450 mA, and no limitation. Signal-to-noise ratio (SNR), dose-length product (DLP), estimated effective dose (ED), and image quality were assessed.


RESULTS
Mean SNR of aorta was comparable among protocols, but that of liver was somewhat lower in 210-mA than in 450-mA and no-limitation protocols (p<0.05). Mean DLP with 210-mA (533.8 mGy cm) was reduced by 31% from that with 450-mA (768.4 mGy cm) and by 38% from that with no-limitation protocol (861.3 mGy cm), respectively. Image quality was slightly degraded (p<0.017) with 210 mA relative to the others in thorax and pelvis, but no difference was found in diagnostic acceptability.


CONCLUSIONS
For whole-body CT using multidetector CT mounted with a high heat-capacity X-ray tube, an appropriate tube current limitation setting may help reduce excessive radiation dose without significant compromise in diagnostic acceptability.
Departments of Radiology, Gifu University Hospital, 1-1 Yanagido, Gifu 501-1194, Japan; Radiology Services, Gifu University Hospital, 1-1 Yanagido, Gifu 501-1194, Japan. Electronic address: masa_gif@yahoo.co.jp.
Masayuki
M
Kanematsu
Departments of Radiology, Gifu University Hospital, 1-1 Yanagido, Gifu 501-1194, Japan.
Hiroshi
H
Kondo
Radiology Services, Gifu University Hospital, 1-1 Yanagido, Gifu 501-1194, Japan.
Toshiharu
T
Miyoshi
Departments of Radiology, Gifu University Hospital, 1-1 Yanagido, Gifu 501-1194, Japan.
Satoshi
S
Goshima
Departments of Radiology, Gifu University Hospital, 1-1 Yanagido, Gifu 501-1194, Japan.
Yoshifumi
Y
Noda
Departments of Radiology, Gifu University Hospital, 1-1 Yanagido, Gifu 501-1194, Japan.
Yukichi
Y
Tanahashi
Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
Kyongtae T
KT
Bae
D000008:Abdominal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D000328:Adult; D000368:Aged; D002985:Clinical Protocols; D003287:Contrast Media; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement; D011857:Radiographic Image Interpretation, Computer-Assisted; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D059629:Signal-To-Noise Ratio; D013899:Thoracic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D014057:Tomography, X-Ray Computed / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods
D003287:Contrast Media
CT; Image quality; Radiation exposure; Tube current limitation; Whole body