Quantitatively accurate activity measurements with a dedicated cardiac SPECT camera: Physical phantom experiments.

Area of Science:

• Nuclear Medicine
• Medical Imaging Physics

Background:

• Dedicated cardiac SPECT cameras with CZT detectors offer improved sensitivity and resolution.
• Traditional scatter correction methods may be complicated by CZT detector characteristics like low-energy tails.

Purpose of the Study:

• To validate the quantitative accuracy and reproducibility of easily implemented correction techniques for myocardial SPECT using a CZT-detector gamma camera.
• To assess the impact of attenuation correction (AC), scatter correction (SC), and partial volume correction (PVC) on quantitative measurements.

Main Methods:

• Used an anthropomorphic torso phantom with simulated cardiac activity and lesions for (99m)Tc-SPECT acquisitions.
• Acquired SPECT images using a dedicated cardiac CZT camera and CT for AC.
• Reconstructed images with various combinations of corrections: no corrections (NC), AC, AC+SC (dual-energy window modified for CZT), AC+PVC, and AC+SC+PVC.

Main Results:

• Attenuation and scatter corrections (ACSC) significantly reduced mean absolute activity measurement errors compared to no corrections (NC) and AC alone (p < 0.001).
• Combined ACSC and PVC further reduced errors, achieving a mean error of 5% ± 4%.
• Partial volume correction provided significant accuracy improvements in images with elevated background activity but not with low background activity.

Conclusions:

• Quantitative cardiac (99m)Tc SPECT measurements are achievable with dedicated CZT cameras using attenuation and scatter corrections.
• Partial volume correction enhances accuracy, particularly in higher background activity scenarios.
• The validated correction techniques are easily implemented and improve the reliability of cardiac SPECT imaging.