Radius dependence of FP-CIT quantification: a Monte Carlo-based simulation study.

Area of Science:

• Neuroimaging
• Nuclear Medicine
• Radiochemistry

Background:

• Dopamine transporter (DAT) imaging using Single-Photon Emission Computed Tomography (SPECT) is vital for clinical and research applications.
• Semi-quantitative analysis is essential for interpreting SPECT scans but is influenced by factors like the radius of rotation (ROR).
• Understanding ROR's impact is critical for reliable DAT imaging results.

Purpose of the Study:

• To systematically evaluate how ROR influences apparent tracer binding in DAT SPECT imaging.
• To identify and describe methods for correcting ROR-induced variations in tracer binding.
• To assess the impact of ROR on different semi-quantification techniques.

Main Methods:

• Monte Carlo simulations of digital brain phantoms with varying disease states and ROR (13-30 cm).
• Analysis using four distinct semi-quantification methods, including different volumes of interest (VOIs).
• Application of a partial volume correction (PVC) method.

Main Results:

• Conventional 3D semi-quantification showed a 2.5–3.1% decrease in measured striatal binding per cm increase in ROR.
• Recovery-corrected quantification yielded negligible effects of ROR on binding measurements.
• The observed effects were consistent across different disease states.

Conclusions:

• Increasing ROR causes significant underestimation of binding ratios due to partial volume effects, especially in research settings.
• Standardizing acquisition ROR can prevent these errors; correction methods are feasible but depend on the quantification approach.
• Accurate DAT imaging requires careful consideration of ROR and appropriate correction strategies.