Publication | Closed Access
Dual‐slice spiral versus single‐slice spiral scanning: Comparison of the physical performance of two computed tomography scanners
79
Citations
0
References
1996
Year
The study compares single‑slice and dual‑slice spiral CT scanners. The authors evaluated image noise, contrast and spatial resolution, radiation dose, and slice‑sensitivity using physical measurements and computer simulations with 180° and 360° interpolation. Noise is identical for both scanners and depends only on interpolation; dual‑slice scanners provide superior longitudinal resolution at higher pitches and allow scan rates up to pitch 4, making them preferable when higher throughput is needed without compromising image quality.
In this paper we deal with two types of spiral scanners; one is a single‐slice spiral scanner, while the other employs dual‐slice technology into spiral scanning. Physical performance parameters, including image noise, contrast resolution, spatial resolution (transversal and longitudinal), and radiation exposure are measured. Computer simulations based on two interpolation methods (180° and 360° linear interpolation) are also used in evaluating the slice‐sensitivity profile (SSP) and noise. The results show that the noise behaves in the same way for both types of scanners. The noise change, relative to that of the standard scan with the same scanning parameters, depends solely on the interpolation algorithm. Table speed and scanner geometry (either single slice or dual slice) have no effect on the noise value. For the given table speed, as well as individual detector collimation (slice width) the dual‐slice scan results in better longitudinal resolution (SSP) compared to a single‐slice scan if the scan is obtained with nonoverlapping slices (pitch greater than 2). This is because the dual‐slice scan obtains twice the number of nonoverlapped projections for the same length, which reduces the degradation of the slice profile by using more densely arranged projections (in the longitudinal direction) for the interpolation. In the dual‐slice scanner the workable scan rate is extended up to pitch 4 compared to a pitch of 2 for the single‐slice scanner. Therefore, the dual‐slice spiral scanner is preferred in applications requiring an increased scan rate with comparative image quality.