Design and Optimization of a Phantom for Testing Gamma Camera Resolution

Indianapolis, IN

Imaging phantoms are used to characterize performance of imaging systems. Currently, common practice is to use standard imaging phantoms to test the performance of only common imaging setups (i.e., large field-of-view general-purpose gamma cameras). Recent surges in the development of task-specific cameras may also present unique imaging geometries ahead of imaging phantom development. Lack of diverse phantom designs and standards inhibits proper testing of these novel imaging systems. However, the advances in 3D printing technologies, alongside 3D printing becoming more prevalent and affordable, has allowed for easier production of flexible phantom designs for task-specific cameras. Furthermore, new exotic 3D printing filaments that include heavy metals, are attractive for use in situations where blocking medium and high energy x-rays and gamma rays is desired (due to their high attenuation). We present a 3D printed bar phantom containing 8 sets of features ranging from 1.2mm to 8mm, which we have designed for testing the resolution of two novel gamma cameras. We have also tested the attenuation of several candidate filaments for this phantom, tungsten-infused-ABS and copper-infused-PLA among others. Lessons learned from initial 3D prints were used to optimize the design of this phantom, to use less filament and alleviate other printer-specific issues that were affecting printing quality.