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

Abstract 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 [18F]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. Competing Interest Statement The authors have declared no competing interest. Funding Statement This study did not receive any funding Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Footnotes Manuscript Length reduced and restructured with updated references Data Availability All data produced in the present study are available upon reasonable request to the authors