Crister Ceberg
Professor
Surface-guided tomotherapy improves positioning and reduces treatment time : A retrospective analysis of 16 835 treatment fractions
Författare
Summary, in English
Purpose: In this study, we have quantified the setup deviation and time gain when using fast surface scanning for daily setup/positioning with weekly megavoltage computed tomography (MVCT) and compared it to daily MVCT. Methods: A total of 16 835 treatment fractions were analyzed, treated, and positioned using our TomoTherapy HD (Accuray Inc., Madison, USA) installed with a Sentinel optical surface scanning system (C-RAD Positioning AB, Uppsala, Sweden). Patients were positioned using in-room lasers, surface scanning and MVCT for the first three fractions. For the remaining fractions, in-room laser was used for setup followed by daily surface scanning with MVCT once weekly. The three-dimensional (3D) setup correction for surface scanning was evaluated from the registration between MVCT and the planning CT. The setup correction vector for the in-room lasers was assessed from the surface scanning and the MVCT to planning CT registration. The imaging time was evaluated as the time from imaging start to beam-on. Results: We analyzed 894 TomoTherapy treatment plans from 2012 to 2018. Of all the treatment fractions performed with surface scanning, 90 % of the residual errors were within 2.3 mm for CNS (N = 284), 2.9 mm for H&N (N = 254), 8.7 mm for thorax (N = 144) and 10.9 for abdomen (N = 134) patients. The difference in residual error between surface scanning and positioning with in-room lasers was significant (P < 0.005) for all sites. The imaging time was assessed as total imaging time per treatment plan, modality, and treatment site and found that surface scanning significantly reduced patient on-couch time compared to MVCT for all treatment sites (P < 0.005). Conclusions: The results indicate that daily surface scanning with weekly MVCT can be used with the current target margins for H&N, CNS, and thorax, with reduced imaging time.
Avdelning/ar
- Radiotherapy Physics
- LUCC: Lunds universitets cancercentrum
Publiceringsår
2020-08
Språk
Engelska
Sidor
139-148
Publikation/Tidskrift/Serie
Journal of Applied Clinical Medical Physics
Volym
21
Issue
8
Dokumenttyp
Artikel i tidskrift
Förlag
American College of Medical Physics
Ämne
- Other Physics Topics
- Radiology, Nuclear Medicine and Medical Imaging
Nyckelord
- helical
- radiotherapy
- SGRT
- surface scanning
- tomotherapy
Status
Published
Forskningsgrupp
- Radiotherapy Physics
ISBN/ISSN/Övrigt
- ISSN: 1526-9914