Verifying tumor position during stereotactic body radiation therapy delivery using (limited-arc) cone beam computed tomography imaging

Colien Hazelaar, Max Dahele, Stefan Scheib, Ben J Slotman, Wilko F A R Verbakel

Research output: Contribution to journalArticleAcademicpeer-review

13 Citations (Scopus)


BACKGROUND AND PURPOSE: Proof of tumor position during stereotactic body radiotherapy (SBRT) delivery is desirable. We investigated if cone-beam CT (CBCT) scans reconstructed from (collimated) fluoroscopic kV images acquired during irradiation could show the dominant tumor position.

MATERIALS AND METHODS: Full-arc CBCT scans were reconstructed using FDK filtered back projection from 38kV fluoroscopy datasets (16 patients) continuously acquired during volumetric modulated spine SBRT. CBCT-CT match values were compared to the average spine offset values found using template matching+triangulation of the individual kV images. Multiple limited-arc CBCTs were reconstructed from fluoroscopic images acquired during lung SBRT of an anthropomorphic thorax phantom using 20-180° arc lengths and for 3 breath-hold lung SBRT patients.

RESULTS: Differences between 3D CBCT-CT match results and average spine offsets found using template matching+triangulation were 0.1±0.1mm for all directions (range: 0.0-0.5mm). For limited-arc CBCTs of the thorax phantom, the automatic 3D CBCT-CT match results for arc lengths of 80-180° were ≤1mm. 20° CBCT reconstruction still allowed for positional verification in 2D.

CONCLUSIONS: (Limited-arc) CBCT reconstructions of kV images acquired during irradiation can identify the dominant position of the tumor during treatment delivery.

Original languageEnglish
Pages (from-to)355-362
Number of pages8
JournalRadiotherapy and oncology
Issue number3
Publication statusPublished - Jun 2017


  • Cone-Beam Computed Tomography
  • Humans
  • Image Processing, Computer-Assisted
  • Journal Article
  • Lung Neoplasms
  • Phantoms, Imaging
  • Radiosurgery
  • Radiotherapy, Image-Guided
  • Research Support, Non-U.S. Gov't
  • Retrospective Studies

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