DVH-based inverse planning for LDR pancreatic brachytherapy

Area of Science:

• Medical Physics
• Oncology
• Radiotherapy

Background:

• Pancreatic cancer is a common malignancy requiring effective treatment.
• Low-dose-rate (LDR) brachytherapy shows promise for pancreatic cancer but faces challenges with planning time and tumor dose.
• Current inverse planning methods for LDR brachytherapy have limitations in speed and plan quality.

Purpose of the Study:

• To present and validate a novel inverse planning method utilizing simulated annealing (SA) for LDR brachytherapy in pancreatic cancer.
• To address the limitations of long preoperative planning times and insufficient tumor dose in current pancreatic cancer brachytherapy.
• To develop a method that optimizes tumor dose coverage while minimizing dose to organs at risk.

Main Methods:

• Simulated annealing (SA) algorithm was employed for the inverse planning process.
• Parallel computation and a rapid dose field estimation algorithm were integrated to accelerate planning.
• A unique length-control method was implemented to manage and restrict the dose to organs at risk.
• Validation involved calculating dose-volume histogram metrics and measuring planning time.

Main Results:

• The SA method achieved average differences in tumor V100 of 5.01% (small tumors) and 2.3% (large tumors).
• Dose to organs at risk showed average differences of 1.32% (small tumors) and -4.49% (large tumors).
• Inverse planning times were significantly reduced: 1.63 ± 0.26 s (small tumors) and 3.81 ± 0.51 s (large tumors), with improved plan quality compared to other methods.

Conclusions:

• A novel SA-based inverse planning method for pancreatic cancer LDR brachytherapy has been developed.
• This method effectively delivers the prescribed tumor dose while safeguarding organs at risk.
• The significantly reduced planning time and enhanced plan quality indicate readiness for clinical application.