Use of Thermoluminescence Dosimetry for QA in High-Dose-Rate Skin Surface Brachytherapy with Custom-Flap Applicator.
Francesco Manna, Mariagabriella Pugliese, Francesca Buonanno, Federica Gherardi, Eva Iannacone, Giuseppe La Verde, Paolo Muto, Cecilia Arrichiello
Author Information
Francesco Manna: Department of Physics "E. Pancini", Federico II University, 80126 Naples, Italy.
Mariagabriella Pugliese: Department of Physics "E. Pancini", Federico II University, 80126 Naples, Italy. ORCID
Francesca Buonanno: Radiotherapy Unit, Istituto Nazionale Tumori, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Fondazione G. Pascale, 80131 Naples, Italy. ORCID
Federica Gherardi: Radiotherapy Unit, Istituto Nazionale Tumori, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Fondazione G. Pascale, 80131 Naples, Italy.
Eva Iannacone: Radiotherapy Unit, Istituto Nazionale Tumori, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Fondazione G. Pascale, 80131 Naples, Italy. ORCID
Giuseppe La Verde: Department of Physics "E. Pancini", Federico II University, 80126 Naples, Italy. ORCID
Paolo Muto: Radiotherapy Unit, Istituto Nazionale Tumori, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Fondazione G. Pascale, 80131 Naples, Italy.
Cecilia Arrichiello: Radiotherapy Unit, Istituto Nazionale Tumori, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Fondazione G. Pascale, 80131 Naples, Italy.
Surface brachytherapy (BT) lacks standard quality assurance (QA) protocols. Commercially available treatment planning systems (TPSs) are based on a dose calculation formalism that assumes the patient is made of water, resulting in potential deviations between planned and delivered doses. Here, a method for treatment plan verification for skin surface BT is reported. Chips of thermoluminescent dosimeters (TLDs) were used for dose point measurements. High-dose-rate treatments were simulated and delivered through a custom-flap applicator provided with four fixed catheters to guide the Iridium-192 (Ir-192) source by way of a remote afterloading system. A flat water-equivalent phantom was used to simulate patient skin. Elekta TPS Oncentra Brachy was used for planning. TLDs were calibrated to Ir-192 through an indirect method of linear interpolation between calibration factors (CFs) measured for 250 kV X-rays, Cesium-137, and Cobalt-60. Subsequently, plans were designed and delivered to test the reproducibility of the irradiation set-up and to make comparisons between planned and delivered dose. The obtained CF for Ir-192 was (4.96 ± 0.25) μC/Gy. Deviations between measured and TPS calculated doses for multi-catheter treatment configuration ranged from -8.4% to 13.3% with an average of 0.6%. TLDs could be included in clinical practice for QA in skin BT with a customized flap applicator.
