Enhanced efficiency and ergonomics of an intraoperative automated prostate brachytherapy delivery technique

Abstract 

Introduction

In 2003, the Tom Baker Cancer Centre started a prostate brachytherapy program using Iodine-125 seeds, intraoperative treatment planning, and an automated remote afterloader, the seedSelectron. Over a 3-month period in 2004–2005, technologic changes were implemented with the intent of reducing the time spent in the operating room and improving ergonomics for the radiation oncologist/surgeon. New commercial software including inverse planning was installed, concurrent needle insertion and seed train building was implemented, and additional hardware (a slave monitor) was connected to the system.

Purpose

To demonstrate that, with these enhancements, dosimetry is not compromised, whereas efficiency is significantly improved.

Methods

Interactive inverse planning was used to create the treatment plans in the operating room. Seed-spacer trains were built concurrently with each needle's insertion guided by rotating the ultrasound probe to the correct sagittal plane using the Needle Navigator feature. Needles were built, inserted, and delivered one needle at a time. Needle coordinate and insert positions were verified on the live ultrasound image displayed on both the slave monitor positioned above the patient's pelvis and the operator console. Dosimetry parameters (D₉₀ and V₁₀₀), numbers of seeds, and OR times were compared for 20 patients before and 11 patients after the implementation of the concurrent insertion and build protocol combined with inverse planning and the slave monitor.

Results

Operating room (OR) times (probe in to probe out) were reduced by 33min and the number of seeds per unit volume by 3% on an average. The majority of the decrease in time is due to the concurrent building and insertion of needles. Before and after the new technique, average postplan D₉₀ and V₁₀₀ values at 4 weeks after the implant were the same to within 4Gy and 0.1%, respectively. The range (max–min) of D₉₀ decreased by 20% of the mean dose and the V₁₀₀ range decreased by 6% with the new technique. Adding the slave monitor improved quality assurance of the delivery process and ergonomics for physicians.

Conclusions

The concurrent insertion and build protocol, together with inverse planning and the slave monitor, have decreased OR times with greater consistency in the delivered dose distribution.

Keywords: Prostate brachytherapy, Iodine-125, Intraoperative, Automated delivery