Program Information
Portal Dosimetry with Elekta IViewDose:Performance of the Simplified Commissioning Approach Versus Full Commissioning
M Kydonieos1*, A Folgueras1 , L Florescu1 , T Cybulski1 , N Marinos1 , G Thompson1 , A Sayeed1 , R Rozendaal2 , I Olaciregui-Ruiz2 , A Subiel3 , I Silvestre Patallo3 , (1)Elekta Limited, Crawley,West Sussex, (2) Netherlands Cancer Institute - Antoni van Leeuwenhoek, Amsterdam, Noord-Holland, (3) National Physical Laboratory, London
Presentations
TH-AB-201-10 (Thursday, August 4, 2016) 7:30 AM - 9:30 AM Room: 201
Purpose: Elekta recently developed a solution for in-vivo EPID dosimetry (iViewDose, Elekta AB, Stockholm, Sweden) in conjunction with the Netherlands Cancer Institute (NKI). This uses a simplified commissioning approach via Template Commissioning Models (TCMs), consisting of a subset of linac-independent pre-defined parameters. This work compares the performance of iViewDose using a TCM commissioning approach with that corresponding to full commissioning. Additionally, the dose reconstruction based on the simplified commissioning approach is validated via independent dose measurements.
Methods: Measurements were performed at the NKI on a VersaHD™ (Elekta AB, Stockholm, Sweden). Treatment plans were generated with Pinnacle 9.8 (Philips Medical Systems, Eindhoven, The Netherlands). A farmer chamber dose measurement and two EPID images were used to create a linac-specific commissioning model based on a TCM. A complete set of commissioning measurements was collected and a full commissioning model was created.
The performance of iViewDose based on the two commissioning approaches was compared via a series of set-to-work tests in a slab phantom. In these tests, iViewDose reconstructs and compares EPID to TPS dose for square fields, IMRT and VMAT plans via global gamma analysis and isocentre dose difference.
A clinical VMAT plan was delivered to a homogeneous Octavius 4D phantom (PTW, Freiburg, Germany). Dose was measured with the Octavius 1500 array and VeriSoft software was used for 3D dose reconstruction. EPID images were acquired. TCM-based iViewDose and 3D Octavius dose distributions were compared against the TPS.
Results: For both the TCM-based and the full commissioning approaches, the pass rate, mean γ and dose difference were >97%, <0.5 and <2.5%, respectively. Equivalent gamma analysis results were obtained for iViewDose (TCM approach) and Octavius for a VMAT plan.
Conclusion: iViewDose produces similar results with the simplified and full commissioning approaches. Good agreement is obtained between iViewDose (simplified approach) and the independent measurement tool.
Funding Support, Disclosures, and Conflict of Interest: This research is funded by Elekta Limited
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