Liquid fiducial marker applicability in proton therapy of locally advanced lung cancer

Jonas Scherman Rydhög, Rosalind Perrin, Rasmus Irming Jølck, Francis Gagnon-Moisan, Klaus Richter Larsen, Paul Clementsen, Steen Riisgaard de Blanck, Gitte Fredberg Persson, Damien Charles Weber, Tony Lomax, Thomas Lars Andresen, Per Munck af Rosenschold

    Research output: Contribution to journalJournal articleResearchpeer-review


    Background and purpose: We investigated the clinical applicability of a novel liquid fiducial marker (LFM) for image-guided pencil beam scanned (PBS) proton therapy (PBSPT) of locally advanced lung cancer (LALC). Materials and methods: The relative proton stopping power (RSP) of the LFM was calculated and measured. Dose perturbations of the LFM and three solid markers, in a phantom, were measured. PBSPT treatment planning on computer tomography scans of five patients with LALC with the LFM implanted was performed with 1-3 fields. Results: The RSP was experimentally determined to be 1.164 for the LFM. Phantom measurements revealed a maximum relative deviation in dose of 4.8% for the LFM in the spread-out Bragg Peak, compared to 12-67% for the solid markers. Using the experimentally determined RSP, the maximum proton range error introduced by the LFM is about 1. mm. If the marker was displaced at PBSPT, the maximum dosimetric error was limited to 2 percentage points for 3-field plans. Conclusion: The dose perturbations introduced by the LFM were considerably smaller than the solid markers investigated. The RSP of the fiducial marker should be corrected in the treatment planning system to avoid errors. The investigated LFM introduced clinically acceptable dose perturbations for image-guided PBSPT of LALC.
    Original languageEnglish
    JournalRadiotherapy & Oncology
    Issue number3
    Pages (from-to)393-399
    Number of pages7
    Publication statusPublished - 2017


    • Beam perturbation
    • Liquid fiducial marker
    • Lung cancer
    • Proton therapy


    Dive into the research topics of 'Liquid fiducial marker applicability in proton therapy of locally advanced lung cancer'. Together they form a unique fingerprint.

    Cite this