Improvement of image quality using interpolated projection data estimation method in SPECT

Area of Science:

• Medical Imaging
• Nuclear Medicine

Background:

• Standard single photon emission computed tomography (SPECT) acquisition uses limited projection angles (e.g., 60-90 directions) with coarse sampling (4-6 degrees).
• This coarse sampling results in missing projection data between adjacent angles, potentially impacting image quality.

Purpose of the Study:

• To develop and evaluate an interpolation method for generating missing SPECT projection data.
• The goal is to improve SPECT image quality by interpolating data acquired at coarse sampling intervals.

Main Methods:

• A weighted average interpolation method, termed the interpolated projection data estimation (IPDE) method, was developed.
• The IPDE method generated projection data at 1-degree intervals from data acquired at coarser angles.
• The method was validated using digital phantom, physical phantom, and clinical brain SPECT data (Tc-99m ECD).

Main Results:

• Interpolation with the IPDE method reduced streak artifacts in SPECT images.
• The signal-to-noise ratio (S/N) and contrast ratios were improved post-interpolation.
• Normalized mean square error values remained comparable to original images, indicating preserved accuracy.

Conclusions:

• The developed interpolation method effectively enhances SPECT image quality.
• Improved image quality and depiction capabilities can be achieved without extending acquisition time.
• The method offers potential for improved SPECT imaging, even with reduced acquisition times.