Dosimetric Performance Evaluation of MLC-based and Cone-based 3D Spatially Fractionated LATTICE Radiotherapy

Area of Science:

• Radiation Oncology
• Medical Physics
• Radiotherapy Planning

Background:

• 3D LATTICE radiotherapy (LRT) offers precise dose delivery.
• Comparing multi-leaf collimator (MLC)-based and cone-based LRT is crucial for optimizing treatment.
• Understanding valley-peak dose patterns is essential for treatment efficacy and safety.

Purpose of the Study:

• To dosimetrically compare MLC-based and cone-based 3D LRT plans.
• To evaluate the impact of LATTICE design parameters on valley-peak ratios.
• To assess the dosimetric accuracy and treatment duration of both systems.

Main Methods:

• Seven different 3D LATTICE designs were created by varying vertex diameter, separation, and volume ratio.
• Treatment plans were generated using CyberKnife and Varian RapidArc systems.
• Dosimetric verification was performed using Thermoluminescent Dosimeters (TLD), EBT3 films, and Electronic Portal-Imaging Devices (EPID).

Main Results:

• Valley-peak ratios showed minimal differences between MLC-based and cone-based plans across various LATTICE designs.
• Dosimetric verification confirmed good agreement between calculated and measured doses for both systems.
• MLC-based plans were found to be more suitable for single-fraction treatments due to shorter treatment durations.

Conclusions:

• Both MLC-based and cone-based 3D LRT plans demonstrate comparable dose-volume histograms.
• Cone-based plans may offer advantages in achieving smaller valley-peak ratios.
• MLC-based plans are preferable for single-fraction treatments considering treatment time.