Intraoperative optimized inverse planning for prostate brachytherapy: Early experience

Purpose: To demonstrate the feasibility of an intraoperative inverse planni ng technique with advanced optimization for prostate seed implantation. Methods and Materials: We have implemented a method for optimized inverse p lanning of prostate seed implantation in the operating room (OR), based on the genetic algorithm (GA) driven Prostate Implant Planning Engine for Radi otherapy (PIPER). An integrated treatment planning system was deployed, whi ch includes real-time ultrasound image acquisition, treatment volume segmen tation, GA optimization, real-time decision making and sensitivity analysis , isodose and DVH evaluation, and virtual reality navigation and surgical g uidance. Ten consecutive patients previously scheduled for implantation wer e included in the series. Results: The feasibility of the technique was established by careful monito ring of each step in the OR and comparison with conventional preplanned imp lants. The median elapsed time for complete image capture, segmentation, GA optimization, and plan evaluation was 4, 10, 2.2, and 2 min, respectively. The dosimetric quality of the OR-based plan was shown to be equivalent to the corresponding preplan. Conclusion: An intraoperative optimized inverse planning technique was deve loped for prostate brachytherapy. The feasibility of the method was demonst rated through an early clinical experience. (C) 1999 Elsevier Science Inc.