# An Enhanced Voxel-by-Voxel Filament Extrusion-Based Method for Realistic Radiological Phantoms: A Breast Phantom Case

## TL;DR

This paper presents a new 3D printing method that improves the accuracy of creating realistic breast phantoms from MRI data using precise control of filament flow and printing speed.

## Contribution

The novel contribution is a dual-parameter control strategy that adjusts extrusion rate and printing speed in real-time per voxel to enhance phantom fidelity.

## Key findings

- Calibration showed a strong linear correlation (R = 0.99) between HUs, extrusion rate, and speed.
- CT scans confirmed high anatomical accuracy and HU distribution in the printed breast phantom.
- The method effectively reduces under-extrusion and improves responsiveness and accuracy in soft tissue phantom fabrication.

## Abstract

This study introduces a novel enhanced voxel-by-voxel fused filament fabrication approach utilizing a custom 3D printer. The key innovation is the simultaneous, real-time manipulation of both filament flow and printing speed per voxel. By adjusting the printing speed proportionally to the extrusion rate, the method ensures sufficient time for precise material deposition, effectively countering under-extrusion effects and significantly improving the process’s responsiveness and accuracy. The method was validated through a calibration process and in the fabrication of a breast phantom derived from a patient’s MRI data. Calibration demonstrated a strong linear correlation between HUs, extrusion rate, and speed, with a coefficient of R = 0.99. CT scans of the phantom confirmed consistent replication of the expected HU distribution and anatomical features, visually demonstrating high correlation with the original patient images. The dual-parameter control strategy successfully enhances the fidelity of soft tissue phantoms fabrication. Future work will focus on adapting the method for high-speed printing and multi-material applications.