TY  - JOUR
A1  - Blanck, Oliver
A1  - Masi, Laura
A1  - Chan, Mark K. H.
A1  - Adamczyk, Sebastian
A1  - Albrecht, Christian
A1  - Damme, Marie-Christin
A1  - Loutfi-Krauss, Britta
A1  - Alraun, Manfred
A1  - Fehr, Roman
A1  - Ramm, Ulla
A1  - Siebert, Frank-Andre
A1  - Stelljes, Tenzin Sonam
A1  - Poppinga, Daniela
A1  - Poppe, Björn
T1  - High resolution ion chamber array delivery quality assurance for robotic radiosurgery : commissioning and validation
T2  - Physica medica
N2  - Purpose: High precision radiosurgery demands comprehensive delivery-quality-assurance techniques. The use of a liquid-filled ion-chamber-array for robotic-radiosurgery delivery-quality-assurance was investigated and validated using several test scenarios and routine patient plans.
Methods and material: Preliminary evaluation consisted of beam profile validation and analysis of source–detector-distance and beam-incidence-angle response dependence. The delivery-quality-assurance analysis is performed in four steps: (1) Array-to-plan registration, (2) Evaluation with standard Gamma-Index criteria (local-dose-difference ⩽ 2%, distance-to-agreement ⩽ 2 mm, pass-rate ⩾ 90%), (3) Dose profile alignment and dose distribution shift until maximum pass-rate is found, and (4) Final evaluation with 1 mm distance-to-agreement criterion. Test scenarios consisted of intended phantom misalignments, dose miscalibrations, and undelivered Monitor Units. Preliminary method validation was performed on 55 clinical plans in five institutions.
Results: The 1000SRS profile measurements showed sufficient agreement compared with a microDiamond detector for all collimator sizes. The relative response changes can be up to 2.2% per 10 cm source–detector-distance change, but remains within 1% for the clinically relevant source–detector-distance range. Planned and measured dose under different beam-incidence-angles showed deviations below 1% for angles between 0° and 80°. Small-intended errors were detected by 1 mm distance-to-agreement criterion while 2 mm criteria failed to reveal some of these deviations. All analyzed delivery-quality-assurance clinical patient plans were within our tight tolerance criteria.
Conclusion: We demonstrated that a high-resolution liquid-filled ion-chamber-array can be suitable for robotic radiosurgery delivery-quality-assurance and that small errors can be detected with tight distance-to-agreement criterion. Further improvement may come from beam specific correction for incidence angle and source–detector-distance response.
KW  - Delivery quality assurance
KW  - Liquid filled MicroLion ion chamber array
KW  - Stereotactic body radiation therapy
KW  - CyberKnife robotic radiosurgery
Y1  - 2017
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/42754
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-427542
SN  - 1120-1797
SN  - 1724-191X
N1  - © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
VL  - 32
IS  - 6
SP  - 838
EP  - 846
PB  - Elsevier
CY  - Amsterdam [u. a.]
ER  -