A standardized workflow for the development and manufacturing of tissue-equivalent anthropomorphic phantoms for radiotherapy using 3D-printing.

Objective.This study aims to establish a standardized workflow for developing highly realistic, anatomically, and dosimetrically equivalent three-dimensional printing (3DP) phantoms for adaptive and patient-specific radiotherapy. Despite recent advances in 3DP technology, the lack of standardization in phantom development limits reproducibility and comparability across studies.Approach.A systematic standardized workflow was designed comprising material characterization, calibration, and phantom fabrication. Various 3DP materials were printed and characterized for relative electron density (RED) and effective atomic number (Zeff) using dual-energy computed tomography (CT). The measured properties were compared to ICRU44 human tissue reference values to identify suitable materials for each tissue of interest. A calibration matrix (CM), specific to each filament and 3D printer, was developed by varying infill density and volumetric flow rate to optimize printing parameters for each tissue. Using this workflow, an anthropomorphic head phantom and two thorax phantoms (one multi-material and one dual-material) were modelled from a digital-, synthetic CT scan and manufactured.Main result.The head phantom verification scan showed a maximum mean deviation of 6.04% in RED and 3.00% inZeffrelative to CM-optimized values. The multi-material thorax phantom exhibited higher deviations of 8.27% in RED and 12.6% inZeff, while the dual-material thorax phantom showed smaller differences of 2.14% and 10.3% in RED andZeff, respectively.Significance.The proposed standardized workflow provides a first quantitative and reproducible approach that incorporates reference tissue properties, inter-printer variability, and filament without increasing workload. It offers a practical foundation for producing anatomically and compositionally accurate 3DP phantoms, supporting broader clinical implementation and improving patient-specific radiotherapy outcomes.