[Accuracy of Modulation Transfer Function for Target Size and Field of View in a Circular Edge Strategy Using the CT Image Measurement Program].
OBJECTIVE
The purpose of this study was to evaluate the effects of target diameter and display-field of view (D-FOV) in modulation transfer function (MTF) by circular edge strategy using the computed tomography (CT) image measurement program "CTmeasure".


METHODS
We calculated the MTF (MTF(edge)) using the circular edge strategy applied to cylindrical phantom (200 mmφ) that inserted with cylinders have 10, 20, 30, and 40 mm diameters. The phantom images were reconstructed using filtered back projection method varied with D-FOV (240, 320, 400, and 500 mm). The study compared both MTF(edge) and MTF(wire) at MTF50% and MTF(10%) for target diameter and D-FOV, respectively.


RESULTS
The MTF(edge) by the different of target diameter indicated in rough compatibility. However, MTF(edge) of D-FOV diameters (320, 400, and 500 mm) decreased in the high frequency range.


CONCLUSIONS
The circular edge strategy for MTF depended on the D-FOV, however, it was little dependent on target diameter using the CT image measurement program "CTmeasure".
Department of Radiological Technology, Kurashiki Central Hospital.
Masaaki
M
Fukunaga
Hideo
H
Onishi
Norikazu
N
Matsutomo
Hiroyuki
H
Yamamoto
D019047:Phantoms, Imaging; D012984:Software; D014057:Tomography, X-Ray Computed