An automated optimization tool for high-dose-rate (HDR) prostate brachytherapy with divergent needle pattern

Area of Science:

• Medical Physics
• Radiation Oncology
• Robotics

Background:

• Focal high-dose-rate (HDR) brachytherapy is emerging for prostate cancer, potentially reducing treatment toxicity compared to whole-gland therapy.
• Optimal needle placement is crucial for focal HDR prostate cancer treatment, ideally guided by Magnetic Resonance (MR) imaging.
• Current MR systems have space limitations hindering MR-guided needle placement, necessitating innovative solutions.

Purpose of the Study:

• To develop an automated inverse dose planning optimization tool for focal HDR prostate brachytherapy utilizing a novel divergent needle insertion configuration.
• To enable precise dose distribution optimization for focal prostate lesions using a single-rotation-point robotic device within an MR environment.

Main Methods:

• Development of a complete optimizer workflow to determine the center of rotation, needle angulations, and dwell times for divergent needle insertions.
• Implementation of an automated inverse planning approach that does not require pre-selection of dose constraints or weighting factors.
• Validation of the optimizer through a planning study on ten patients with varying treatment volumes, using 2-14 needle insertions.

Main Results:

• The developed optimizer successfully determined optimal parameters for focal HDR prostate brachytherapy planning.
• Clinically acceptable treatment plans were achieved on average using only four needle insertions, significantly fewer than the maximum used in the study.
• The total computation time for the optimizer workflow was consistently below 20 minutes.

Conclusions:

• The automated inverse dose planning tool is effective for focal HDR prostate brachytherapy with divergent needle configurations.
• This approach facilitates MR-guided focal treatment, potentially reducing toxicity while maintaining plan quality.
• The developed system offers a promising solution for optimizing focal prostate cancer treatment planning in conjunction with novel robotic delivery systems.