Measurement techniques, modeling strategies and pitfalls to avoid when implementing a mini MLC in a non dedicated planning system

Abstract

Background and Purpose: Ghent University Hospital investigated the feasibility of the Pinnacle® system for planning intracranial stereotactic treatments. The aim was to perform precise dose computation using the collapsed cone engine for treatment delivery with the Moduleaf mini-MLC mounted on an Elekta accelerator. Material and Methods: The Moduleaf® was commissioned using dose rate corrected data recorded by a diamond detector and using data measured by cylindrical chambers each limited to restricted field sizes. Results: Automatic modeling resulted in clinical relevant dose errors up to 10%. Using manual modeling in Pinnacle®, for clinical applicable fields a 2%/2 mm agreement between modeled data and measurements was obtained. Conclusion: The overall accuracy of the collapsed cone algorithm is within tolerances for single fraction stereotactic treatments. © 2007 Urban & Vogel.