Question

What are the acceptable ranges of:

1. CT linearity,

2. CT uniformity and

3. Dosimetry.

Answer 1

1.Current CT scanners have a spatial resolution of 0.5–0.625 mm in the z-axis, and approximately 0.5 mm in the x- to y-axes. ... However, the current resolution of CT is not optimal for precise stenosis grading of the coronary arteries, which measure in the 5-mm range proximally, and ≤2 mm distally.

2.The CT uniformity must be in the range of 0 ± 4HU.

3..By optimizing the dose range for each color channel, they obtained a system that has both precision and accuracy below 1.5%, and the optimized ranges are 0-4 Gy for the red channel, 4-50 Gy for the green channel, and above 50 Gy for the blue channel.