Penalized maximum-likelihood reconstruction for improving limited-angle artifacts in a dedicated head and neck PET system.

Penalized maximum-likelihood reconstruction for improving limited-angle artifacts in a dedicated head and neck PET system. Phys Med Biol. 2020 Apr 23;: Authors: Zhang H, Wang Y, Qi J, Abbaszadeh S Abstract Positron emission tomography (PET) suffers from limited spatial resolution in current head and neck cancer management. We are building a dual-panel high-resolution PET system to aid the detection of tumor involvement in small lymph nodes (< 10 mm in diameter). The system is based on cadmium zinc Telluride (CZT) detectors with cross-strip electrode readout (1 mm anode pitch and 5 mm cathode pitch). One challenge of the dual-panel system is that the limited angular coverage of the imaging volume leads to artifacts in reconstructed images, such as the elongation of lesions. In this work, we leverage a penalized maximum-likelihood (PML) reconstruction for the limited-angle PET system. The dissimilarity between the image to be reconstructed and a prior image from a low-resolution whole-body scanner is penalized. An image-based resolution model is incorporated into the regularization. Computer simulations were used to evaluate the performance of the method. Results demonstrate that the elongation of the 6-mm and 8-mm diameter hot spheres is eliminated with the regularization strength being 0.02 or larger. The PML reconstruction yields higher contrast recovery coefficient of hot spheres compared to the maximum-likelihood reconstruction...
Source: Physics in Medicine and Biology - Category: Physics Authors: Tags: Phys Med Biol Source Type: research