Cadaveric verification of the Eclipse AAA algorithm for spine SBRT treatments with titanium hardware

Area of Science:

• Medical Physics
• Radiation Oncology
• Biomedical Engineering

Background:

• Spine stereotactic body radiation therapy (SBRT) requires precise dose calculations.
• Surgically implanted hardware, such as titanium, can introduce artifacts in treatment planning.
• Accurate modeling of these artifacts is crucial for effective SBRT.

Purpose of the Study:

• To evaluate the accuracy of the Eclipse Analytical Anisotropic Algorithm for dose calculation in spine SBRT.
• To assess the algorithm's performance with titanium implants.
• To compare dose calculation accuracy using standard and extended CT scales.

Main Methods:

• A human cadaver spine with titanium implants was used for planning and delivery simulations.
• Treatment plans were created using standard and extended CT scales with different artifact overrides.
• Volumetric modulated arc therapy (VMAT) plans were delivered, and dose was measured using Gafchromic film.
• Gamma analysis with a 2%/2 mm criteria was used to compare calculated and measured doses.

Main Results:

• Gamma passing rates in a homogeneous phantom were ≥99.6%.
• Passing rates in the non-implanted spine section were ≥99.3%.
• Passing rates in the titanium-implanted spine section ranged from 98.6% to 99.5%.

Conclusions:

• The Eclipse Analytical Anisotropic Algorithm accurately models titanium implants in spine SBRT.
• Both standard and extended CT scales yield accurate dose calculations.
• The algorithm is suitable for VMAT spine SBRT with titanium hardware.