Radiochromic film EBT3 calibration for linear accelerator in 10 MV

Abstract

Radiochromic film is used to applications in dosimetry have become increasingly significant for studies on radiotherapy. Due to sensitivity to exposure to ionizing radiation, radiochromic films are commonly used to obtain dose distribution maps and for calibration curves. The calibration curves in the radiochromic films can be use radiochromic films as a dosimetry method and then seek the generation of images with lower dose deposition and higher diagnostic quality. When ionizing radiation interacts with matter it generates energy deposition. Radiation dosimetry is important for medical applications of ionizing radiation due to the increasing demand for diagnostic radiology and radiotherapy. The film is a dose measurement method that records the energy deposition by the darkening of its emulsion. Radiochromic films have a little visible light sensitivity and respond better to ionizing radiation exposure. The aim of this study is to obtain the resulting calibration curve by the irradiation of radiochromic film strips, making it possible to relate the darkening of the film with the absorbed dose, to measure doses in experiments with X-ray beam of 10 MeV in Linear Accelerator. The objective of this study is to obtain the calibration curves of the radiographic film for exposure with X-ray beam in Linear Accelerator scanner for realize measures of typical doses found in radiotherapy. It was used Gafchromic EBT Radiochromic Film, which shows little sensitivity to visible light and a response in the range of 0.1 to 10 Gy for X-ray beam. In the experiments, a Solid Water Phantom, with a 30x30x2.0 cm³. The strips were scanned and processed using the ImageJ software to obtain the intensity values resulting from the absorbed radiation by grayscale. The darkening responses on film strips according to the doses were observed and they allowed obtaining the corresponding numeric values to the darkening for each specific dose value. From the numerical values of darkening, a calibration curve was obtained.