Performance evaluation and fundamental problem of the ACTA scanner

The limiting resolution of the ACTA scanner was 2.0 mm in diameter with the acrylic resin bar pattern in water phantom, 1.5 mm in diameter with the alminum spoke pattern in water phantom, and 1.0 mm in diameter at 1.0 percent and 4.0 mm in diameter at less than 0.1 percent of the contrast medium solution in MIX-Dp phantom. The modulation transfer function of the acrylic resin phantom in water was maximum 3.3 cycles/cm. The ACTA value of the attenuation coefficient corresponded to a picture element with 6 at the one degree scan and 9 at the two degree scan. The skin exposure dose of the skull and abdomen for a complete scan was 1.1 rads and 1.4 rads at the direction where the beam angle traveled at ninety degrees from the initial position of x-ray tube. The room dose of the tube leakage and beam scatter for a complete scan was 10 mR/hr in 50 cm on the bilateral sides from the tube and 0.15 mR/hr at the wall 3 m distant from the gantry. (auth.)