Purpose: The purpose of this project was to design and evaluate a 3D printed phantom for evaluating spatial resolution and PET to CT registration for PET/CT scanners
Methods: A model was designed in tinkerCAD (AutoDesk, San Rafael, CA) a computer-aided design software. The design was created such that it would place capillary tubes at the locations indicated by task group report 126 for spatial resolution evaluation of PET/CT scanners. This includes 1 cm, 10 cm, and 20 cm from the isocenter in one direction and another capillary tube 10 cm from the isocenter in an orthogonal direction. The print also includes a bracket so it can mount to existing CT phantom holders which are common to most PET/CT scanners. The design was separated into three separate parts to ensure it would not require the use of 3D-printed supports. The design was then printed on a consumer-grade 3D printer, Flashforge CreatorPro (Flashforge, Jinhua City, China). The location of placed capillary tubes was measured to verify dimensional accuracy. Then it was loaded with radioactive capillary tubes and imaged to demonstrate the utility for registration purposes. Additionally, FWHM values were measured
Results: The capillary tubes were all at the appropriate locations with less than 1 mm variation from the planned distances from the isocenter. The image of the capillary tubes was also acquired and reconstructed. Each was successfully visualized and identified in the correct location. The fused reconstruction was indicated good registration between the PET and CT datasets. The FWHM values are summarized in supplemental materials.
Conclusion: This phantom was created and required less than 2 hours to print on a consumer-grade 3D printer. It demonstrated the capability to function as an accessible and functional complement to the tools necessary for following task group 126 for PET/CT acceptance testing and ongoing quality control testing.