Automatic tube current modulation technique for multidetector CT: is it effective with a 64-detector CT?
To investigate whether it is possible to obtain adequate images at uniform image noise levels and reduced radiation exposure with our automatic tube current modulation (ATCM) technique for 64-detector CT. The study population consisted of 64 patients with known or suspected lung or abdominal disease. We used a 64-detector CT scanner (LightSpeed VCT, GE Healthcare, Waukesha, WI, USA) and a combined angular and longitudinal tube current modulation technique (Smart mA, GE Healthcare, Waukesha, WI, USA) to examine 34 patients. The scanning parameters were identical; the minimum and maximum tube current thresholds were 50 and 800 mA, respectively. For study of the constant tube current technique, 30 additional patients were examined at 350 mA. The CT number and image noise (SD of the CT number) were measured in the 64 patients at six levels, i.e., the center of the left ventricle, the liver dome, the porta hepatis, the center of the spleen and the right and left renal pelvis. When we used the ATCM technique, the mean image noise ranged from 8.40 at the center of the left ventricle to 11.31 at the porta hepatis; the mean tube current ranged from 105.9 mAs at the center of the left ventricle to 169.6 mAs at the center of the spleen. The mean dose reduction rate per constant tube current at 175 mAs ranged from 3.1 to 39.5%. By use of the ATCM technique, it is possible to maintain a constant image noise level with a 64-detector CT.
Funama
Yoshinori
Y
Department of Radiological Sciences, School of Health Sciences, Kumamoto University, Kuhonji, Kumamoto, Japan. yfunama@hs.kumamoto-u.ac.jp
Awai
Kazuo
K
Hatemura
Masahiro
M
Shimamura
Masamitchi
M
Yanaga
Yumi
Y
Oda
Seitaro
S
Yamashita
Yasuyuki
Y
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001331:Automation; D005260:Female; D006801:Humans; D007682:Kidney Pelvis / Q000000981:diagnostic imaging / Q000473:pathology; D008099:Liver / Q000000981:diagnostic imaging / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D011860:Radiography, Abdominal / Q000295:instrumentation* / Q000379:methods; D013154:Spleen / Q000000981:diagnostic imaging / Q000473:pathology; D015898:Tomography Scanners, X-Ray Computed; D014057:Tomography, X-Ray Computed / Q000295:instrumentation* / Q000379:methods; D055815:Young Adult
AJR Am J Roentgenol. 2005 Dec;185(6):1525-30
16304007
Eur J Radiol. 2007 Mar;61(3):534-40
17092681
Radiology. 2004 Mar;230(3):619-28
14739312
Radiology. 2005 Aug;236(2):671-5
16040924
Br J Radiol. 2001 Sep;74(885):836-40
11560832
Radiology. 2004 Dec;233(3):649-57
15498896
Radiology. 2005 Jul;236(1):318-25
15987983
Radiographics. 2004 Nov-Dec;24(6):1679-91
15537976
Eur Radiol. 2006 Oct;16(10):2137-46
16609862
Radiographics. 2002 Nov-Dec;22(6):1541-53
12432127
Radiology. 2003 Sep;228(3):857-63
12881576
Radiology. 2004 Oct;233(1):241-9
15454622
Radiographics. 2006 Mar-Apr;26(2):503-12
16549613
Br J Radiol. 2006 Jan;79(937):56-61
16421406
Radiology. 2004 Nov;233(2):515-22
15358847
Med Phys. 1999 Nov;26(11):2248-53
10587205
AJR Am J Roentgenol. 2006 Mar;186(3):673-9
16498094
Eur Radiol. 2000;10(2):391-4
10663775
Radiology. 2005 Oct;237(1):213-23
16126917