Shading correction assisted iterative cone-beam CT reconstruction.

Shading correction assisted iterative cone-beam CT reconstruction.
Phys Med Biol. 2017 Oct 27;62(22):8495-8520
Authors: Yang C, Wu P, Gong S, Wang J, Lyu Q, Tang X, Niu T
Abstract
Recent advances in total variation (TV) technology enable accurate CT image reconstruction from highly under-sampled and noisy projection data. The standard iterative reconstruction algorithms, which work well in conventional CT imaging, fail to perform as expected in cone beam CT (CBCT) applications, wherein the non-ideal physics issues, including scatter and beam hardening, are more severe. These physics issues result in large areas of shading artifacts and cause deterioration to the piecewise constant property assumed in reconstructed images. To overcome this obstacle, we incorporate a shading correction scheme into low-dose CBCT reconstruction and propose a clinically acceptable and stable three-dimensional iterative reconstruction method that is referred to as the shading correction assisted iterative reconstruction. In the proposed method, we modify the TV regularization term by adding a shading compensation image to the reconstructed image to compensate for the shading artifacts while leaving the data fidelity term intact. This compensation image is generated empirically, using image segmentation and low-pass filtering, and updated in the iterative process whenever necessary. When the compensation image is determined, the objective function is minimi...

Source: Physics in Medicine and Biology - October 27, 2017 Category: Physics Authors: Yang C, Wu P, Gong S, Wang J, Lyu Q, Tang X, Niu T Tags: Phys Med Biol Source Type: research