Development and dosimetric evaluation of a low-cost 3D-Printed PLA head CTDI phantom and CT parameter comparison with...

Commercial polymethyl methacrylate (PMMA) computed tomography dose index (CTDI) phantoms are widely used for CT dose assessment, but their cost and limited availability may restrict routine quality assurance, especially in resource-limited settings. This study evaluated the feasibility of a low-cost 3D-printed polylactic acid (PLA) head CTDI phantom as a complementary to commercial PMMA phantoms for CT dosimetry.

A 160-mm-diameter PLA head CTDI phantom with five dosimetry holes was fabricated using fused deposition modeling. Its elemental composition, density, effective atomic number, electron density, Hounsfield units (HU), and CT dosimetry parameters were characterized. Measurements were performed on 128-slice Ingenuity Philips and GE Discovery scanners, at 80, 120, and 140 kV. CTDI was measured at two different times and then compared with PMMA.

PLA showed properties close to PMMA, with differences of 5.08% in density, -0.015% in effective atomic number, and -4.46% in electron density. PLA HU values were lower than PMMA, ranging from 22.5 to 45.3 HU on Philips and 25.1-49.1 HU on GE. CTDIvol deviations between PLA and PMMA ranged from -9.00% to -2.82% in November 2025 and from -5.78% to -3.83% in June 2026. These deviations remained within <10%, which was generally considered acceptable for comparative phantom-based CT dosimetry.

The PLA CTDI phantom showed good effective atomic number, electron density, and dosimetric agreement with the standard PMMA phantom across two CT systems and two measurement time points.

3D-printed PLA CTDI phantom could offer a practical, low-cost complementary tool for comparative CTDI measurement, education, protocol optimization, and quality assurance.