Scatter correction improves concordance in SPECT MPI with a dedicated cardiac SPECT solid-state camera

Area of Science:

• Nuclear Medicine
• Medical Imaging
• Cardiology

Background:

• Photon attenuation and scatter degrade image quality in conventional gamma cameras.
• Evaluation of scatter correction (SC) for novel solid-state cardiac cameras is limited.
• Cadmium-zinc-telluride (CZT) detectors offer potential advancements in cardiac imaging.

Purpose of the Study:

• To assess the accuracy of dual-energy-window (DEW) scatter correction (SC) on CZT cardiac cameras.
• To compare DEW-SC images from a CZT camera with those from a conventional SPECT camera.
• To evaluate the impact of SC on myocardial perfusion imaging using Tc-99m-tetrofosmin.

Main Methods:

• A modified DEW SC method was developed for CZT detectors, accounting for primary photons in the lower energy window.
• Phantom experiments were conducted to estimate DEW correction parameters.
• Clinical data from 108 patients were analyzed, comparing images reconstructed with no correction (NC), attenuation correction (AC), and AC with DEW-SC from both CZT and conventional SPECT cameras.

Main Results:

• Excellent correlation (r ≥ 0.94) was observed between summed stress/rest scores (SSS/SRS) from both cameras.
• Attenuation correction (AC) reduced the mean difference between cameras for SSS/SRS compared to NC.
• DEW-SC on the CZT camera reduced bias observed without SC, and AC/SC images showed no significant difference between cameras, despite increased noise.

Conclusions:

• Dual-energy-window scatter correction (DEW-SC) is feasible for CZT cardiac cameras.
• DEW-SC produces myocardial perfusion images comparable to conventional SPECT cameras.
• While SC increases noise on CZT images, it does not introduce bias relative to conventional systems.