Script-based implementation of automatic grid placement for lattice stereotactic body radiation therapy

Area of Science:

• Radiation Oncology
• Medical Physics
• Cancer Treatment

Background:

• Spatially fractionated radiation therapy (SFRT) shows promise for large tumors with heterogeneous doses.
• Lattice stereotactic body radiation therapy (SBRT) uses inverse optimization for precise dose localization.

Purpose of the Study:

• To evaluate an automated heuristic algorithm for sphere placement in lattice SBRT treatment planning.
• To compare automated sphere placement with manual methods in terms of efficiency and accuracy.

Main Methods:

• A script-based algorithm for sphere placement was implemented in a treatment planning system.
• The script was applied to 22 cases, comparing sphere distribution, protocol violations, and time with manual placement.
• Re-planning was performed using script-generated spheres to assess plan quality.

Main Results:

• The script placed more spheres (mean 13.8) than manual placement by dosimetrists (10.8-12.0) and physicists (12.7).
• Script-based sphere generation was significantly faster (2.5 min) than manual placement (19.3-29.9 min).
• Plan quality indices were comparable, with OAR constraints met in most cases.

Conclusions:

• An automated script effectively places spheres for lattice SBRT according to protocol rules.
• Script-produced sphere placement is superior to manual placement regarding sphere number and rule adherence.
• This automated approach offers a more efficient and accurate method for lattice SBRT planning.