Unit:
Κατεύθυνση Ιατρική Φυσική-ΑκτινοφυσικήLibrary of the School of Health Sciences
Author:
Papadopoulou Eleni
Supervisors info:
Γεωργία Λυμπεροπούλου, Λέκτορας, Ιατρική Σχολή, ΕΚΠΑ
Παντελής Καραΐσκος, Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ
Ελευθέριος Παππάς, Επίκουρος Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ
Original Title:
Πειραματική επιβεβαίωση στερεοτακτικής ακτινοθεραπείας πνεύμονα με το σύστημα CyberKnife
Translated title:
Experimental validation of stereotactic lung radiotherapy with the CyberKnife system
Summary:
The aim of this study is the end-to-end dosimetric and geometrical verification of the stereotactic lung radiotherapy using the CyberKnife system. This process ensures that patients receive the dose predicted by the treatment system. The purpose of this work is the dosimetric verification of treatment plans using two different dose calculation methods and the comparison of the techniques.
CyberKnife® (CK) offers three options for fiducial-free lung SBRT with the Lung Optimized Treatment (LOT) function. The Synchrony Respiratory Tracking System uses 2-view, 1-view and 0-view tracking for treatments. The accuracy of the entire process is imperative for the therapeutic outcome and the elimination of side effects.
The CIRS dynamic thorax phantom model 008A was used for the experimental verification of LOT treatments (2-View, 1-View, 0-View). Two CT scans of the phantom were acquired at extreme positions to simulate the exhale/inhale phases. Treatment plans using an MLC collimator were generated with the Accuray Precision Treatment Planning System v3.3.1.2 and the (a) Monte Carlo (MC) and (b) Finite Size Pencil Beam with lateral scaling correction (FSPB-LS) algorithms for dose calculation. Two-dimensional absolute dose measurements were performed in axial and sagittal planes with calibrated Gafchromic EBT3-XLT films and the FILMQA Pro software.
The film results for static delivery and 2-view tracking closely matched the corresponding TPS distributions, verifying the accuracy of dose calculation and the ability of the Synchrony tracking system to monitor and adapt accurately to the tumor position within experimental uncertainties (dose differences within 2-5% in the tumor and penumbra regions for MC-calculated plans). Full tumor coverage was achieved in the case of spine-based tracking (0-View) for the modeled tumor motion.
In conclusion, the geometric and dosimetric accuracy of the CK system using Synchrony tracking for lung SBRT was verified within experimental uncertainties.
Main subject category:
Health Sciences
Keywords:
CyberKnife, CIRS Dynamic Thorax Phantom, Dosimetry, EBT3-XLT, FilmQA Pro
File:
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thesis.pdf
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