Optimized acquisition time and image sampling for dynamic SPECT of Tl-201

Area of Science:

• Nuclear Medicine
• Medical Imaging Physics
• Pharmacokinetics

Background:

• Dynamic single photon emission computerized tomography (SPECT) offers potential for quantitative physiological parameter estimation.
• Advancements in scatter and attenuation correction enhance dynamic SPECT accuracy.
• Thallium-201 (Tl-201) exhibits kinetics suitable for dynamic SPECT analysis.

Purpose of the Study:

• To systematically determine minimum data acquisition times for quantitative dynamic SPECT.
• To investigate optimal sampling requirements for estimating physiological parameters using Tl-201.
• To compare full dynamic sampling schedules (DynSS) with optimized sampling schedules (OSS).

Main Methods:

• Monte Carlo simulations were used to evaluate two sampling schemes: continuous acquisition (30-240 min) and split-session (10-45 min dynamic + delayed static).
• Tissue time-activity curves with realistic noise were generated based on Tl-201 kinetic data from canine studies.
• Rate constants (K1-K4) and derived parameters (K1, Vd) were estimated and compared between sampling strategies.

Main Results:

• Optimum sampling schedules (OSS) demonstrated reliable estimation of blood flow-related K1 and Vd, comparable to full dynamic sampling schedules (DynSS).
• A 30-minute continuous acquisition sufficed for K1 estimation.
• A split-session protocol (30-min dynamic + 3-h static) reliably estimated both K1 and Vd, avoiding prolonged acquisitions.

Conclusions:

• Optimized sampling schedules can significantly reduce SPECT acquisition times while maintaining accuracy for physiological parameter estimation.
• The developed methodology is applicable for optimizing dynamic SPECT protocols with other tracers.
• Shorter, optimized SPECT protocols enhance patient comfort and resource efficiency.