Enhancing PET/CT Assessment with Porous 3D-Printed Grids – A Pilot Study
Listed in
This article is not in any list yet, why not save it to one of your lists.Abstract
Objective
Phantom experiments are widely used for standardisation in positron emission tomography (PET), but current practices to do not necessarily reflect clinical reality (e.g. targets have visible walls) and require meticulous phantom preparation for repeatability. Three-dimensional (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 to fillable targets, and characterizes the same.
Approach
Acrylonitrile butadiene styrene cubic grids (4 cm/side) with varying pore distance (5, 7, 10 mm) and solidity (50%, 60%, 70%) were printed. Spherical targets of 10, 15 and 20 mm were also incorporated for quantitation and detectability. Grids were immersed in a [ 18 F] fluorodeoxyglucose solution (activity: ∼7 kBq/mL), with soap, within a Jaszczak phantom cylinder. Five consecutive acquisitions were repeated on five different days (Day 0,1,4-6) using a Discovery MI PET/CT (GE Healthcare). Hounsfield units (HU), recovery coefficient (RC) and dilution coefficient (DC) were the metrics used for analysis. A Friedman test was utilized to study global statistical significance across days, with Wilcoxon tests for pairwise differences between days.
Main Results
Within the grids, HU values (range −40 to −21, Day 0) increased with time (range −28 to −4, Day 6). The 5 mm pore distance grid provided features with the best resolution. PET quantification showed consistent results across trials, confirming robustness. Achieved target-to-background ratios (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 RC were in range of 0.4 – 1.2. RC 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.
