Note Jpn J Radiol Technol 1999 ; 55 (11) :
Spatial Variation of the Section Sensitivity Profile in Helical CT

SHOICHI KATSUTA, KOUZOU HANAI, TAKEO KUNII, HARUKI KIMURA,
WATARU IMABAYASHI, and YOSHIHISA MURAMATSU
Department of Radiology, National Cancer Center Central Hospital
Received Aug. 28, 1998; Revision accepted Aug. 9, 1999; Code No.251
Summary
The section sensitivity profile(SSP)is adequate to express the properties of helical CT images. Although SSP measurement has been performed only at the center of the imaging field, we applied it to off-center positions using a metal bead and controlled tracking technique. The experimental results indicated that SSP curves vary in the imaging field according to the relative position of the x-ray focus. The results were in agreement with computer simulations.
Key words: Computed tomography, Helical scanning, Section sensitivity profile, Spatial variation, Simulation