Details

Autor(en) / Beteiligte

• Pappas, Eleftherios P.
• Peppa, Vasiliki
• Hourdakis, Costas J.
• Karaiskos, Pantelis
• Papagiannis, Panagiotis

Titel

On the use of a novel Ferrous Xylenol-orange gelatin dosimeter for HDR brachytherapy commissioning and quality assurance testing

Ist Teil von

• Physica medica, 2018-01, Vol.45, p.162-169

Ort / Verlag

Italy: Elsevier Ltd

Erscheinungsjahr

2018

Link zum Volltext

Quelle

Elsevier ScienceDirect Journals Complete

Beschreibungen/Notizen

• •TrueView, a commercially available 3D chemical dosimeter, is employed for the first time.•3D dosimetry is performed using optical computed tomography for skin brachytherapy.•Experimental results are compared to MC, standard and advanced TPS dosimetry algorithms.•Albeit recommended, experimental benchmarking studies of advanced TPS dosimetry are scarce. To evaluate a commercially available Ferrous-Xylenol Orange-Gel (FXG) dosimeter (TrueView™) coupled with Optical-Computed Tomography (OCT) read out, for 3D dose verification in an Ir-192 superficial brachytherapy application. Two identical polyethylene containers filled with gel from the same batch were used. One was irradiated with an 18 MeV electron field to examine the dose-response linearity and obtain a calibration curve. A flap surface applicator was attached to the other to simulate treatment of a skin lesion. The dose distribution in the experimental set up was calculated with the TG-43 and the model based dose calculation (MBCA) algorithms of a commercial treatment planning system (TPS), as well as Monte Carlo (MC) simulation using the MCNP code. Measured and calculated dose distributions were spatially registered and compared. Apart from a region close to the container’s neck, where gel measurements exhibited an over-response relative to MC calculations (probably due to stray light perturbation), an excellent agreement was observed between measurements and simulations. More than 97% of points within the 10% isodose line (80 cGy) met the gamma index criteria established from uncertainty analysis (5%/2 mm). The corresponding passing rates for the comparison of experiment to calculations using the TG-43 and MBDCA options of the TPS were 57% and 92%, respectively. TrueView™ is suitable for the quality assurance of demanding radiotherapy applications. Experimental results of this work confirm the advantage of the studied MBDCA over TG-43, expected from the improved account of scatter radiation in the treatment geometry.