Enhancing PET/CT Assessment with Porous 3D Printed Grids– A Pilot Study

Objective Phantom experiments are widely used for standardisation in positron emission tomography (PET), but current practices to do not necessarily reflect clinical reality and require meticulous phantom preparation for repeatability. 3D printing can reduce these limitations by optimizing preparatory methods and improving phantom features. This work proposes employing 3D-printed porous grids as an alternative mechanism to emulate targets with contrast. Approach Acrylonitrile butadiene styrene (ABS) cubic grids (4 cm/side) with varying design characteristics and targets were printed. Grids were immersed in a [ 18 F]FDG solution with soap within a conventional phantom. Five consecutive acquisitions were repeated on five different days (Day 0, 1,4-6) using a Discovery MI PET/CT. Target representation index(TRI) and dilution coefficient (DC) were the metrics used for analysis. Friedman test was utilized to study global statistical significance across days. Main Results PET images resulted in clear demarcation of various contrast regions produced by the dilution grid. Quantitative metrics showed consistent results across trials, confirming robustness. Dilutions achieved (mean±std. dev.) were 1.93±0.14, 2.44±0.2, and 3.01±0.08 vs. 2, 2.5 and 3.33 (theoretical), respectively. Observed TRI were in range of 0.4 – 1.2. Correlation across days was strong (p≥0.67), and days 1 and 5 had the best pairwise comparable results. Significance 3D-printed grids offer a reliable, reproducible alternative for PET/CT assessment. Dozens of targets with background were produced with a single tracer administration. CT attenuation throughout the phantom mimicked water, giving good PET representation of wall-free targets.