Towards accurate partial volume correction in ^99mTc oncology SPECT: perturbation for case-specific resolution...

Area of Science:

• Nuclear Medicine
• Medical Imaging
• Radiochemistry

Background:

• Optimal partial volume correction (PVC) algorithms for oncology imaging lack consensus.
• Existing PVC methods often assume a spatially invariant point spread function (PSF), which is inaccurate for SPECT.
• This study addresses the need for accurate SPECT quantification using case-specific PSFs.

Purpose of the Study:

• To assess the accuracy of SPECT quantification when applying PVC with a case-specific PSF.
• To evaluate the impact of PSF estimation methods on quantitative accuracy in SPECT imaging.
• To determine the effectiveness of perturbation-based PSF estimation for improving SPECT accuracy.

Main Methods:

• Simulated SPECT [Formula: see text]Tc imaging with various activity distributions relevant to oncology.
• Estimated Gaussian PSFs using perturbation with a small point source in diverse scenarios (position, lesion characteristics, noise).
• Applied PVC using Single Target Correction with perturbation-estimated PSFs and assessed quantitative accuracy of regional mean values.

Main Results:

• Perturbation-estimated PSFs showed dependence on field position and OSEM iterations.
• Convolution with perturbation-estimated PSFs yielded lower root-mean-square error compared to other PSFs.
• PVC using perturbation-estimated PSFs significantly improved quantitative accuracy over uncorrected data or data corrected with unsuitable PSFs.
• Regional mean values in simple and anthropomorphic phantoms were within 0.7% and 1.6% of ground truth, respectively, after correction.

Conclusions:

• Perturbation-based estimation of case-specific PSFs can enhance quantitative SPECT accuracy.
• Sufficient reconstruction iterations (≥5 OSEM) are necessary for optimal results.
• This approach offers a potential method for improving SPECT quantification in clinical oncology.