Coincidence imaging using 2 dual-head gamma-camera systems, with and without attenuation correction

Area of Science:

• Nuclear medicine
• Medical imaging
• Oncology

Background:

• Coincidence imaging offers a pathway for increased 18F-FDG PET imaging in facilities without dedicated PET systems.
• This study evaluates dual-head gamma camera systems for coincidence imaging in tumor detection.

Purpose of the Study:

• To compare the efficacy of coincidence imaging for tumor detection using two gamma camera systems with different detector sizes (5/8-inch vs. 1-inch) in a clinical setting.
• To assess the impact of attenuation correction and CT-fusion on image quality and diagnostic accuracy.

Main Methods:

• Thirty patients underwent imaging with two systems: CoDe5 (5/8-inch detector) and CoDe8 (1-inch detector with X-ray tube).
• Four image sets were compared: CoDe5 without attenuation correction (CoDe5NC), CoDe8 with (CoDe8AC) and without (CoDe8NC) attenuation correction, and fused coincidence-CT images.
• Quantitative analysis included target-to-background (T/Bg) and target-to-nontarget (T/NT) ratios.

Main Results:

• CoDe8AC identified 61 tumor sites, with CoDe8NC detecting 97% and CoDe5NC detecting 88%.
• The 1-inch detector system (CoDe8) showed significantly higher accepted events and improved T/Bg and T/NT ratios compared to the 5/8-inch system (CoDe5), both with and without attenuation correction (P <0.001).
• Attenuation correction further improved T/Bg ratios on CoDe8 images (P <0.0005). Fused images provided clinically relevant data in 20% of patients.

Conclusions:

• Coincidence imaging utilizing 1-inch detectors and attenuation correction enhances image quality and tumor detection rates over 5/8-inch detectors with non-corrected images.
• CT-fusion with coincidence imaging provided clinically relevant information in 20% of cases, underscoring its value in specific patient scenarios.