Concurrent treatment planning for outpatient high dose rate prostate template implants

Area of Science:

• Oncology
• Radiation Oncology
• Medical Physics

Background:

• Locally advanced prostate cancer (B2-C) requires integrated radiotherapy approaches.
• External beam radiotherapy combined with interstitial implant boost is a treatment strategy.
• The need for rapid, automated planning and image integration is critical for effective treatment.

Purpose of the Study:

• To evaluate an integrated external beam radiotherapy and high dose rate (HDR) interstitial implant boost for locally advanced prostate cancer.
• To assess the feasibility and efficiency of a novel, automated treatment planning system.
• To incorporate real-time imaging and dose optimization into the brachytherapy procedure.

Main Methods:

• A treatment planning system was developed integrating imaging, needle guidance, source reconstruction, and dose display.
• The system automated key planning components including reconstruction, optimization, and dose prescription.
• A reproducible rectal reference point was established for dose verification.

Main Results:

• 83 treatments were delivered between November 1991 and November 1992.
• The system facilitated intra-operative treatment decisions due to its speed and interpretability.
• Rectal doses ranged from 35-79% (mean 58%) of the prescribed dose; the first phase of a dose-escalating trial was completed with 22 patients.

Conclusions:

• Outpatient high dose rate brachytherapy is a practical method for boosting locally advanced prostate cancer.
• Rapid treatment planning incorporating on-line ultrasound images enables immediate dose optimization.
• The integrated system demonstrated satisfactory performance in the operating room.