A comparative study on the radiological properties of PEEK and titanium alloy implant materials with extended HU CT imaging

Introduction

This study compares the radiological properties of Polyether Ether Ketone (PEEK) and titanium Alloy (Ti6Al4V) implant materials in reconstructive surgery for head and neck cancer patients undergoing radiotherapy. It focuses on attenuation, scatter in water, dose build-up, and dose near heterogeneity, measured and calculated with the Treatment Planning System using 12-bit and extended HU CT images.

Methods

PEEK and Ti6Al4V slabs were 3D-printed at various thicknesses, and their radiological properties were measured using a Plane Parallel chamber on a Varian UNIQUE linear accelerator with 6 MV photons. Scatter measurements in a water phantom with 3D-printed holders were performed for both materials. The Eclipse TPS was used for dosimetric analysis with the AAA. TPS analysis utilized 12-bit and extended HU CT image sets of the water phantom with slabs.

Results

PEEK showed minimal scattering effects (<1%) and no dose enhancement. Ti6Al4V resulted in 1.5% dose enhancement and 9.1% dose reduction. CT scans with Ti6Al4V exhibited artefacts, causing 4.5% underestimation of dose. HU maximum value for Ti6Al4V was about 6916 in extended HU CT images, saturating at 3017 in 12-bit depth CT. Depth dose curves from TPS for both CT image sets showed no significant variation with AAA, with a dose enhancement of about 2.5% at the slab entrance.

Conclusion

PEEK could be a viable alternative to Ti6Al4V due to its minimal impact on dose distribution. Enhanced radiation effects near Ti6Al4V and high-density artefacts suggest the need for alternatives to high-density materials, making PEEK as a suitable implant material.