- 作者：Anja Betgen ; Tanja Alderliesten ; Jan-Jakob Sonke ; Corine van Vliet-Vroegindeweij ; Harry Bartelink ; Peter Remeijer ; p.remeijer@nki.nl
- 关键词：IGRT ; Breast cancer ; Geometrical uncertainties ; Breath hold ; Surface imaging
- 刊名：Radiotherapy and Oncology
- 出版年：2013
- 出版时间：February, 2013
- 年：2013
- 卷：106
- 期：2
- 页码：225-230
- 全文大小：656 K
Purpose
To quantify set-up uncertainties during voluntary deep inspiration breath hold (DIBH) radiotherapy using 3D-surface imaging in patients with left sided breast cancer.Material and methods
Nineteen patients were included. Cone-beam CT-scan (CBCT) was used for online set-up correction while patients were instructed to perform a voluntary DIBH. The reproducibility of the DIBH during treatment was monitored with 2D-fluoroscopy and portal imaging. Simultaneously, a surface imaging system was used to capture 3D-surfaces throughout CBCT acquisition and delivery of treatment beams. Retrospectively, all captured surfaces were registered to the planning-CT surface. Interfraction, intra-fraction and intra-beam set-up variability were quantified in left-right, cranio-caudal and anterior-posterior direction.
Results
Inter-fraction systematic (¦²) and random (¦Ò) translational errors (1SD) before and after set-up correction were between 0.20-0.50 cm and 0.09-0.22 cm, respectively, whereas rotational ¦² and ¦Ò errors were between 0.08 and 1.56¡ã. The intra-fraction ¦² and ¦Ò errors were ?0.14 cm and ?0.47¡ã. The intra-beam SD variability was ?0.08 cm and ?0.28¡ã in all directions.
Conclusion
Quantification of 3D set-up variability in DIBH RT showed that patients are able to perform a very stable and reproducible DIBH within a treatment fraction. However, relatively large inter-fraction variability requires online image guided set-up corrections.