A Method for Attenuation Correction in Radionuclide Computed Tomography

TLDR

Radionuclide computed tomography reconstruction is hindered by gamma‑ray attenuation, and current algorithms rely on inadequate approximation formulas or slow iterative procedures. This study proposes a simple, effective two‑step attenuation‑correction method for RCT applied to the uncorrected image. The method employs fast filtered back‑projection in the first step and a subsequent correction step to adjust the image. The paper presents a mathematical foundation for the procedure and demonstrates its performance with illustrative computer simulations.

Abstract

The development of algorithms for Radionuclide Computed Tomography (RCT) is complicated by the presence of attenuation of gamma-rays inside the body. Some of the existing RCT reconstruction algorithms apply approximation formulas to the projection data for attenuation correction, while others take attenuation into account through some iterative procedures. The drawbacks of these algorithms are that the approximation formulas commonly used are generally inadequate and the iterative procedures are usually very time-consuming. The method for attenuation correction in RCT, which we propose, applied a simple, effective two-step procedure to the uncorrected image. In this procedure the filtered back-projection algorithm is used for its fast speed. A simple mathematical basis and description of the procedure together with some illustrative computer results are given in this paper.