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Crister Ceberg

Professor

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Surface-guided tomotherapy improves positioning and reduces treatment time : A retrospective analysis of 16 835 treatment fractions

Författare

  • André Haraldsson
  • Sofie Ceberg
  • Crister Ceberg
  • Sven Bäck
  • Silke Engelholm
  • Per E. Engström

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