A practical method for measuring planar spatial resolution with scatter on a CZT gamma camera

Area of Science:

• Medical Imaging Physics
• Nuclear Medicine Technology

Background:

• Accurate characterization of 2D spatial resolution is crucial for gamma camera performance evaluation.
• Traditional methods like the NEMA standard can be time-consuming and complex.
• Developing faster, practical evaluation methods is essential for clinical settings.

Purpose of the Study:

• To propose and validate a simpler, faster method for evaluating 2D spatial resolution with scatter on CZT planar detector gamma cameras.
• To assess the influence of distance on spatial resolution Full Width at Half Maximum (FWHM) using a WEHR collimator.
• To compare the proposed practical method with the established NEMA NU1-2018 standard.

Main Methods:

• Utilized linear sources tilted at various angles relative to the detector axes.
• Compared FWHM measurements from the tilted source method with those from the NEMA NU1-2018 method.
• Acquired data at distances from 0 to 20 cm with and without manufacturer's post-processing image enhancement.

Main Results:

• The tilted source method provided FWHM estimates comparable to the NEMA method, with deviations within 5.62% at 10 cm.
• Spatial resolution FWHM showed minimal decrease beyond 3 cm distance, indicating collimator and digitization limitations.
• Manufacturer's post-processing reduced FWHM by an average of 15%.

Conclusions:

• The practical tilted source method is a quicker alternative to the NEMA method for evaluating CZT planar camera spatial resolution.
• Collimator effects and signal digitization limit spatial resolution measurements at short distances.
• This method offers a practical and efficient solution for assessing spatial resolution under clinical conditions.