Investigation of gamma camera detector uniformity using a dynamic line phantom

Area of Science:

• Nuclear Medicine Imaging
• Medical Physics
• Gamma Camera Technology

Background:

• Assessing gamma camera uniformity is crucial for accurate diagnostic imaging.
• Traditional methods for uniformity assessment can be time-consuming.
• The dynamic line phantom offers a potentially more efficient approach.

Purpose of the Study:

• To investigate the applicability of the dynamic line phantom for determining the uniformity of circular and rectangular field-of-view gamma cameras.
• To compare the dynamic line phantom's performance against established uniformity measurement techniques.

Main Methods:

• Determined count rate-activity and uniformity-count rate functions using the dynamic line phantom on multiple gamma cameras (varying PMTs and field-of-view).
• Evaluated phantom efficacy by comparing results with uniformity values obtained using 99mTc point source and 57-Co sheet source.
• Conducted measurements with and without collimators.

Main Results:

• The dynamic line phantom yielded uniformity values statistically comparable to 99mTc point source and 57-Co sheet source methods.
• This agreement was observed within individually determined optimal count rate ranges for each gamma camera.
• Optimal count rates varied between circular (20,000-30,000 cps) and rectangular (15,000-65,000 cps) field-of-view cameras.

Conclusions:

• The dynamic line phantom is a suitable tool for assessing detector uniformity in gamma cameras.
• Accurate uniformity determination requires measurements to be performed within a well-defined activity (count rate) interval.
• This method provides a reliable alternative for routine quality control in nuclear medicine.