Development and validation of a 3D printed phantom for image quality assessment in fluoroscopy

BACKGROUND: Low-contrast detectability is a key image-quality parameter in fluoroscopy, directly influencing diagnostic accuracy and patient safety. Commercial phantoms such as the CDRAD provide reliable assessments but are costly and lack flexibility for routine use. PURPOSE: To develop and validate a low-cost 3D-printed phantom for fluoroscopy quality control, designed with low-contrast performance similar to the commercial reference standard CDRAD, and to offer a reproducible framework for clinical implementation. This represents an original and accessible strategy for systematic fluoroscopy image-quality assessment. METHODS: The proposed 3D-printed low-contrast phantom (hereafter referred to as the LC phantom) was modeled in a Computer-Aided Design (CAD) software and printed in polylactic acid (PLA) with 100% infill. It features a modular circular design adaptable to different fields of view. Quantitative validation included correlation between theoretical subject contrast (SC) and image-based contrast-to-noise ratio (CNR), with comparisons to the CDRAD under clinically representative beam qualities (65-100 kVp), using additional copper filtration to produce hardened X-ray spectra typical of fluoroscopic practice. Subjective comparison of both phantoms was performed through multicenter testing on four fluoroscopy systems (three mobile and one fixed). RESULTS: ) ranging from 0.88 to 0.99. Visual evaluations yielded mean low-contrast thresholds of 3.11 ± 0.26%, 2.66 ± 0.31%, and 2.70 ± 0.27% for 65, 80, and 100 kVp, respectively, with a maximum deviation of 0.10 SC units relative to the reference phantom, indicating reproducible and consistent performance across the evaluated beam qualities. CONCLUSIONS: The proposed LC phantom is a practical and affordable tool for routine fluoroscopy image quality assessment. Its methodology can be adapted to different beam qualities and institutional protocols, supporting harmonized and accessible image-quality assessment in clinical practice.