Direct reconstruction of single-photon emission computed tomography images using retained matrix elements

Area of Science:

• Medical Imaging
• Nuclear Medicine
• Image Reconstruction

Background:

• Current clinical single-photon emission computed tomography (SPECT) reconstruction relies on filtered backprojection (fast, acceptable images) and iterative reconstruction (slow, high accuracy).
• A need exists for a SPECT reconstruction method balancing speed and accuracy.

Purpose of the Study:

• To develop a novel SPECT reconstruction method combining the speed of filtered backprojection with the accuracy of iterative reconstruction.
• To achieve a direct solution for SPECT reconstruction equations.

Main Methods:

• Computed a direct solution to the linear equations governing SPECT reconstruction.
• Tested the direct reconstruction method using projection data from a cold rod and sphere phantom.

Main Results:

• Direct reconstruction yielded images with resolution equivalent to filtered backprojection.
• The direct method demonstrated a twofold increase in contrast ratio compared to filtered backprojection.
• Reconstruction time was 10 seconds per slice on a Macintosh Quadra 950, significantly faster than typical iterative methods.

Conclusions:

• The developed direct solution method for SPECT reconstruction offers a significant advancement.
• This method provides a favorable balance of speed and image accuracy for clinical applications.
• The direct approach enhances contrast without compromising resolution, offering a faster alternative to iterative techniques.