Carbon Fiber/Polyether Ether Ketone (CF/PEEK) Implants Allow for More Effective Radiation in Long Bones

Area of Science:

• Biomedical Engineering
• Radiotherapy Physics
• Orthopedic Implants

Background:

• Metallic implants complicate radiotherapy planning and dose delivery due to beam attenuation and scattering.
• Metal artifacts obscure follow-up imaging, impacting treatment monitoring.
• Titanium implants can lead to significant dose deviations in surrounding tissues and target lesions.

Purpose of the Study:

• To evaluate the dosimetric impact of titanium versus radiolucent carbon fiber/polyether ether ketone (CF/PEEK) implants in long bone radiotherapy.
• To determine if CF/PEEK implants enable more homogenous radiation application and efficient dose delivery to target volumes.
• To assess the effect of CF/PEEK implants on computed tomography (CT)-based radiation therapy planning and imaging.

Main Methods:

• Bone models (ovine femora) with titanium and CF/PEEK plates/nails were CT-scanned and irradiated in a water phantom.
• Dosimetry films were used to map radiation dosage and distribution patterns.
• Simulations considered different soft-tissue envelopes by varying immersion depths.

Main Results:

• CF/PEEK implants showed significantly lower planned beam attenuation (1-2%) compared to titanium (5-9%).
• The effective radiation dose decrease behind CF/PEEK implants was smaller than with titanium implants.
• CF/PEEK implants resulted in significant reduction of imaging artifacts, while radiation dose was not significantly affected by surrounding soft tissues.

Conclusions:

• CF/PEEK implants facilitate more reliable and effective radiation dose delivery to osseous targets.
• Radiolucent CF/PEEK implants minimize radiotherapy complications associated with metallic implants.
• CF/PEEK intramedullary nails are particularly beneficial for adjuvant radiation therapy in long bones.