Tracking errors in a prototype real-time tumour tracking system

Gregory C. Sharp, Steve B. Jiang, Shinichi Shimizu, Hiroki Shirato

Research output: Contribution to journalArticle

30 Scopus citations


In motion-compensated radiation therapy, radio-opaque markers can be implanted in or near a tumour and tracked in real-time using fluoroscopic imaging. Tracking these implanted markers gives highly accurate position information, except when tracking fails due to poor or ambiguous imaging conditions. This study investigates methods for automatic detection of tracking errors, and assesses the frequency and impact of tracking errors on treatments using the prototype real-time tumour tracking system. We investigated four indicators for automatic detection of tracking errors, and found that the distance between corresponding rays was most effective. We also found that tracking errors cause a loss of gating efficiency of between 7.6 and 10.2%. The incidence of treatment beam delivery during tracking errors was estimated at between 0.8% and 1.25%.

Original languageEnglish (US)
Pages (from-to)5347-5356
Number of pages10
JournalPhysics in Medicine and Biology
Issue number23
Publication statusPublished - Dec 7 2004


ASJC Scopus subject areas

  • Biomedical Engineering
  • Physics and Astronomy (miscellaneous)
  • Radiology Nuclear Medicine and imaging
  • Radiological and Ultrasound Technology

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