Bias and precision of SPECT-based ¹⁷⁷Lu activity-concentration estimation using a ring-configured solid-state versus...

Area of Science:

• Nuclear Medicine
• Medical Imaging
• Radiopharmacy

Background:

• Comparing bias and precision in SPECT imaging is crucial for accurate radionuclide therapy monitoring.
• Dual-headed Anger SPECT and ring-configured CZT SPECT systems have different characteristics for activity-concentration estimation.

Purpose of the Study:

• To compare bias and precision of 177Lu-SPECT activity-concentration estimation between Anger and CZT SPECT systems.
• To evaluate performance at different energy windows (208 keV and 113 keV).

Main Methods:

• Phantom experiments using NEMA PET body and anthropomorphic phantoms with 177Lu and 99mTc.
• Acquisitions performed on GE Discovery 670 (Anger) and GE StarGuide (CZT) systems.
• OS-EM reconstruction with corrections for attenuation, scatter, and resolution.

Main Results:

• Both systems showed similar performance for 177Lu at 208 keV.
• The CZT system demonstrated lower bias and similar CV for 99mTc and 177Lu at 113 keV.
• Both systems tended to overestimate total activity at 113 keV.

Conclusions:

• The ring-configured CZT SPECT system is a viable alternative to Anger SPECT for 177Lu imaging.
• The CZT system offers potential advantages for activity-concentration estimation at 113 keV.
• Further investigation into total activity preservation is warranted for clinical application.