Low-dose, large-angled cone-beam helical CT data reconstruction using algebraic reconstruction techniques

摘要

We report on results on the use of two variants of the algebraic reconstruction techniques (ART) for reconstructing from helical cone-beam computerized tomography (CT) data: a standard one that considers a single ray in an iterative step and a block version which treats simultaneously several cone-beam projections when calculating an iterative step. Both algorithms were implemented using the modified Kaiser-Bessel window functions, also known as blobs, placed on the body-centered cubic (bcc) grid. The algorithms were used to reconstruct phantoms from data collected for the PI-geometry for four different maximum cone-beam angles (2.39, 7.13, 9.46 and 18.43°). Both scattering and quantum noise (for three different noise levels) were introduced to create noisy projections that simulate low-dose examinations. The results presented here (for both noiseless and noisy data sets) point to the facts that, as opposed to a filtered back-projection algorithm, the quality of the reconstructions produced by the ART methods does not suffer from the increase in the cone-beam angle and it is more robust in the presence of noise.