3D-printed headrest for frameless Gamma Knife radiosurgery: Design and validation

Area of Science:

• Medical Physics
• Neurosurgery
• Biomedical Engineering

Background:

• Frameless Gamma Knife stereotactic radiosurgery (SRS) relies on patient immobilization using moldable headrests and thermoplastic masks.
• Fabricating traditional headrests is time-consuming and requires specialized expertise, often constrained by machine geometry.
• Existing methods present challenges in efficiency and accessibility for creating effective immobilization devices.

Purpose of the Study:

• To design and validate a novel three-dimensional (3D)-printed headrest for frameless Gamma Knife SRS.
• To overcome the fabrication difficulties and time constraints associated with conventional moldable headrests.
• To assess the dosimetric properties and immobilization efficacy of the 3D-printed headrest.

Main Methods:

• A 3D model of a headrest was designed and fabricated using 3D printing technology.
• Dosimetric comparison with a standard moldable headrest using an anthropomorphic phantom, ionization chambers, and radiochromic film.
• Patient immobilization efficacy was evaluated through a volunteer study tracking head motion with a surface tracking system.

Main Results:

• Dosimetric analysis showed the 3D-printed headrest was equivalent to the moldable headrest, with ionization chamber readings within 0.55% difference.
• Gamma index analysis of film measurements indicated 98.6% of points within 2% dose difference and 2 mm distance to agreement.
• Volunteer studies revealed no statistically significant difference in head immobilization efficacy between the 3D-printed and moldable headrests (P=0.466).

Conclusions:

• A 3D-printed headrest has been successfully designed and validated for patient immobilization in frameless Gamma Knife SRS.
• The 3D-printed headrest offers a viable alternative, demonstrating comparable dosimetric accuracy and immobilization effectiveness.
• This innovation has the potential to streamline the SRS workflow and improve accessibility to advanced immobilization techniques.