Optimization of SPECT/CT imaging protocols for quantitative and qualitative ^99mTc SPECT

Area of Science:

• Nuclear Medicine
• Medical Imaging
• Radiochemistry

Background:

• Hybrid SPECT/CT systems offer quantitative imaging capabilities comparable to PET/CT.
• Quantitative SPECT requires robust methodological setups for accurate tracer quantitation.

Purpose of the Study:

• To evaluate a specific quantitative reconstruction algorithm for SPECT data.
• To identify an optimized quantitative protocol by assessing image parameters under different acquisition and reconstruction settings.

Main Methods:

• Utilized a 99mTc-filled NEMA phantom for evaluation.
• Assessed quantitative and qualitative image parameters across 16 different protocol parametrizations.
• Investigated the impact of scatter correction weighting factor (k), number of iterations, and sphere volume.

Main Results:

• Activity concentration (ACrec) and signal-to-noise ratio (SNR) were significantly influenced by scatter correction (k), iterations, and sphere volume (p < 0.0001).
• Object-specific scatter correction (k=0.18) reduced underestimation of ACrec compared to default (k=0.47).
• Increased iterations improved ACrec accuracy but decreased SNR; optimal settings balance these factors.

Conclusions:

• Quantitative SPECT imaging is feasible with hybrid SPECT/CT and the evaluated algorithm.
• Recommends task-specific reconstruction protocols (quantitative vs. qualitative) for combined diagnostic and quantitative analysis.
• Individual scatter correction significantly enhances both quantitative and qualitative SPECT imaging results.