Patient-specific online dose verification based on transmission detector measurements

• Verfasst von: Thölking, Johannes [VerfasserIn]
• Verfasst von: Fleckenstein, Jens [VerfasserIn]
• Verfasst von: Sekar, Yuvaraj [VerfasserIn]
• Verfasst von: Lohr, Frank [VerfasserIn]
• Verfasst von: Wenz, Frederik [VerfasserIn]
• Verfasst von: Wertz, Hansjörg [VerfasserIn]
• Titel: Patient-specific online dose verification based on transmission detector measurements
• Verf.angabe: Johannes Thoelking, Jens Fleckenstein, Yuvaraj Sekar, Ramesh Boggula, Frank Lohr, Frederik Wenz, Hansjoerg Wertz
• E-Jahr: 2016
• Jahr: 16 April 2016
• Umfang: 6 S.
• Fussnoten: Gesehen am 20.05.2019
• Titel Quelle: Enthalten in: Radiotherapy and oncology
• Ort Quelle: Amsterdam [u.a.] : Elsevier Science, 1983
• Jahr Quelle: 2016
• Band/Heft Quelle: 119(2016), 2, Seite 351-356
• ISSN Quelle: 1879-0887
• DOI: doi:10.1016/j.radonc.2016.04.003
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: Online dose verification
• Sach-SW: Quality assurance
• Sach-SW: Transmission detector
• K10plus-PPN: 1665938544

Abstract

Background and purpose - Since IMRT-techniques lead to an increasingly complicated environment, a patient specific IMRT-plan verification is recommended. Furthermore, verifications during patient irradiation and 3D dose reconstruction have the potential to improve treatment delivery, accuracy and safety. This study provides a detailed investigation of the new transmission detector (DTD) Dolphin (IBA Dosimetry, Germany) for online dosimetry. - Materials and methods - The clinical performance of the DTD was tested by dosimetric plan verification in 2D and 3D for 18 IMRT-sequences. In 2D, DTD measurements were compared to a pre-treatment verification method and a treatment planning system by gamma index and dose difference evaluations. In 3D, dose-volume-histogram (DVH) indices and gamma analysis were evaluated. Furthermore, the error detection ability was tested with leaf position uncertainties and deviations in the linear accelerator (LINAC) output. - Results - The DTD measurements were in excellent agreement to reference measurements in both 2D (γ3%,3mm=(99.7±0.6)% <1, ΔD±5%=(99.5±0.5)%) and 3D. Only a small dose underestimation (<2%) within the target volume was observed when analyzing DVH-indices. Positional errors of the leaf banks larger than 1mm and errors in LINAC output larger than 2% were identified with the DTD. - Conclusions - The DTD measures the delivered dose with sufficient accuracy and is therefore suitable for clinical routine.