# Experimental determination of effective X-ray attenuation coefficients of 3D-printed materials under clinical mammography spectra

## TL;DR

This study shows how to measure X-ray properties of 3D-printed materials for use in breast imaging tests, using standard equipment.

## Contribution

A new experimental framework was developed to determine X-ray attenuation coefficients of 3D-printed materials under clinical mammography conditions.

## Key findings

- Beam hardening and scatter reduced effective attenuation coefficients by up to 28% in no-grid acquisitions.
- PLA, PET, and resin matched breast tissue-equivalent materials within ±6% attenuation.
- An empirical model provided excellent fits (R² > 0.99) for characterizing beam hardening effects.

## Abstract

3D printing enables the fabrication of customized breast phantoms for image quality assessment in digital mammography (DM) and digital breast tomosynthesis (DBT). A major challenge is the absence of standardized, accessible methods to characterize the attenuation properties of 3D-printed materials under clinical DM/DBT spectra.

An experimental framework was implemented to determine the effective X-ray attenuation coefficient (μ

eff
) of six 3D-printed polymers (PLA, PET, resin, ABS, ABS+, HIPS) and reference breast tissue-equivalent materials (CIRS plates simulating different breast glandular/adipose ratios (BR) and PMMA) using two commercial DM/DBT systems, with and without anti-scatter grid. Step-wedges (0.5–5.5 cm) were imaged across multiple kVp and filter settings. The μ

eff
were obtained from measurements on images and fitted to an empirical model yielding μ

0
(attenuation at thickness tending to zero) and k (decay rate) to characterize beam hardening and scatter influences. 3D-reference material equivalences were evaluated based on μ

eff
and μ

0

.

Beam hardening and scatter reduced μ

eff
with thickness, by 6%–14% with grid and 12%–28% without grid, with scatter contributing 47%–76% of the reduction in no-grid acquisitions. No significant differences were observed between the two mammography systems. Based on μ

eff
values, attenuation equivalences (within ±6%) were identified between 3D-printed and reference breast tissue-equivalent materials: PLA with BR 100/0; PET and resin with BR 70/30 and PMMA; ABS+ with BR 30/70 and BR 50/50. ABS and HIPS showed larger mismatches. The empirical model achieved excellent fits (R2 > 0.99), with μ

0
values preserving attenuation ranking and enabling derivation of equivalent glandular proportions.

This framework demonstrates that routine clinical mammography systems can be used directly, without specialized instrumentation, to characterize 3D-printed materials as tissue surrogates. Several low-cost, widely available polymers were shown to reproduce breast tissue attenuation, supporting the local fabrication of anthropomorphic breast phantoms for realistic and clinically relevant image quality evaluation.