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Target Motion Variability and On-Line Positioning Accuracy during External-Beam Radiation Therapy of Prostate Cancer with an Endorectal Balloon Device = Organmobilität und Lokalisationsbestimmung der Prostata unter Einsatz eines endorektalen Ballons bei der Radiotherapie des Prostatakarzinoms

El-Bassiouni, Mazen ; Davis, J. ; El-Attar, Inas ; Studer, Gabriela ; Lütolf, Urs ; Ciernik, I.

In: Strahlentherapie und Onkologie, 2006, vol. 182, no. 9, p. 531-536

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    Titre
    • Target Motion Variability and On-Line Positioning Accuracy during External-Beam Radiation Therapy of Prostate Cancer with an Endorectal Balloon Device
    Titre traduit ()
    • Organmobilität und Lokalisationsbestimmung der Prostata unter Einsatz eines endorektalen Ballons bei der Radiotherapie des Prostatakarzinoms
    Auteur
    • El-Bassiouni, Mazen. Radiation Oncology, Zurich University Hospital, University of Zurich, Zurich, Switzerland
    • Davis, J.. Radiation Oncology, Zurich University Hospital, University of Zurich, Zurich, Switzerland
    • El-Attar, Inas. Department of Epidemiology and Statistics, National Cancer Institute (NCI), University of Cairo, Cairo, Egypt
    • Studer, Gabriela. Radiation Oncology, Zurich University Hospital, University of Zurich, Zurich, Switzerland
    • Lütolf, Urs. Radiation Oncology, Zurich University Hospital, University of Zurich, Zurich, Switzerland
    • Ciernik, I.. Radiation Oncology, Zurich University Hospital, University of Zurich, Zurich, Switzerland
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • Strahlentherapie und Onkologie, 2006, vol. 182, no. 9, p. 531-536. Urban & Vogel
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:319263
    Summary
    Purpose:: To prospectively define the setup error and the interfraction prostate localization accuracy of the planning target volume (PTV) in the presence of an endorectal balloon (ERB) device. Patients and Methods:: Weekly portal images (PIs) of 15 patients undergoing external-beam radiotherapy were analyzed. Displacements of the isocenter and the center of the ERB were measured. The setup and target motion variability were assessed with regard to the position variability of the ERB. Results:: The setup error was random and target motion variability was largest in the craniocaudal direction. The mean displacement of the isocenter was 2.1 mm (± 1.2 mm SD [standard deviation]), 2.4 mm (± 2.2 mm SD), and 3.8 mm (± 4.0 mm SD) in the left-right, craniocaudal, and anteroposterior directions, respectively (p = 0.1). The mean displacement of the ERB was 2.0 mm (± 1.4 mm SD), 4.1 mm (± 2.0 mm SD), and 3.8 mm (± 3.3 mm SD; p = 0.03). Setup margin and internal margin contributed equally to the PTV margin. Cumulative placement insecurity of the field and the ERB together was 4.0 mm (± 2.1 mm SD) laterally, 6.4 mm (± 2.5 mm SD) craniocaudally, and 7.7 mm (± 7.0 mm SD) anteroposteriorly. The 95% CIs (confidence intervals) were 2.9-5.2 mm, 5.1-7.8 mm, and 3.8-11.5 mm. In 35% of cases, the estimation of the dorsal margin exceeded 1 cm. Conclusion:: Margin estimate dorsally may exceed 1 cm and on-line position verification with an ERB cannot be recommended for dose escalation > 70 Gy