Aplicabilidade de um Protótipo para Determinação da Dose Absorvida Utilizando Equipamentos de Braquiterapia com Fontes de 192Ir

Abstract

In the intention to have a "body of evidence" that can be used in quality control (QA) of hospitals and clinics that provide services for the treatment of patients with malignancies sources Ir - 192 (brachytherapy with high rates of dose) a system with Fricke dosimetry was developed by researchers at the Centro Regional de Ciências Nucleares (CRCN) and is being used in public and private institutions of laboratories throughout the Northeast and Southeast Brazilian, where they are irradiated samples in triplicate with a dose of 150 or 300 cGy over a distance of 2.5 cm from the source. This work aims at the development and improvement of a device to perform the absolute dosimetry of Ir - 192 sources using the Fricke solution contained in a flask. The Fricke solution used was prepared using amounts of ferrous ammonium sulfate, sodium chloride and sulfuric acid diluted in distilled water three pre-established in the literature. The spectrophotometer used was a UV-VIS spectrophotometer (Beckman DU-640 Couter) for measuring the optical density at wavelength 304 nm. The calculation for determining the radial dose takes into account the radial distance and the angle formed with the transverse axis of the source. Could be seen by the obtained results that the states of Pernambuco, Ceará, Paraíba and Piauí are in accordance with the recommendations of international standards of the International Atomic Energy Agency (IAEA), which considers not acceptable a difference greater than 5% of prescribed dose and measured dose.

Keywords

• brachytherapy
• dosimeter
• quality control