TY - JOUR

T1 - Liquid fiducial marker applicability in proton therapy of locally advanced lung cancer

AU - Scherman Rydhög, Jonas

AU - Perrin, Rosalind

AU - Jølck, Rasmus Irming

AU - Gagnon-Moisan, Francis

AU - Larsen, Klaus Richter

AU - Clementsen, Paul

AU - Riisgaard de Blanck, Steen

AU - Fredberg Persson, Gitte

AU - Weber, Damien Charles

AU - Lomax, Tony

AU - Andresen, Thomas Lars

AU - Munck Af Rosenschold, Per

N1 - Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

PY - 2017/3

Y1 - 2017/3

N2 - 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 1mm. 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.

AB - 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 1mm. 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.

KW - Fiducial Markers

KW - Humans

KW - Lung Neoplasms

KW - Phantoms, Imaging

KW - Proton Therapy

KW - Radiotherapy Dosage

KW - Radiotherapy Planning, Computer-Assisted

KW - Tomography, X-Ray Computed

KW - Journal Article

U2 - 10.1016/j.radonc.2016.12.027

DO - 10.1016/j.radonc.2016.12.027

M3 - Journal article

C2 - 28104299

VL - 122

SP - 393

EP - 399

JO - Radiotherapy & Oncology

JF - Radiotherapy & Oncology

SN - 0167-8140

IS - 3

ER -