RESUMO
PET cyclotrons are widely used for producing medical diagnostic radionuclides. The main radionuclide produced in these facilities is the 18F, which is obtained from the [18O (p,n)18F] reaction when 18O-enriched water is bombarded with the proton beams. This work aimed to estimate the radiation source term from the bombardment of an 18O-enriched water target with protons of 16.5 MeV to determine the radiation neutron field around the accelerator.
Assuntos
Ciclotrons , Prótons , Isótopos de Oxigênio , Método de Monte Carlo , ÁguaRESUMO
As CT exams impart high doses to patients in comparison to other radiologist techniques, reliable dosimetry is required. In this work, dosimetry in CT beams was carried out in terms of air kerma index in air or in a phantom measured by a pencil ionization chamber, thermoluminescent (TL) detectors and radiochromic film. Calibration results showed the low energy dependence of all three dosimetric systems for the 100-120kV range, the very high uncertainty of the TL dosimeters in comparison to the other systems and high nonlinearity response in terms of air kerma of the radiochromic film. Measurements with the three systems in a 120kV CT protocol showed an acceptable agreement among the weighted air kerma index values, but TL dosimeters presented the highest uncertainties in the values.
Assuntos
Radiometria/métodos , Tomografia Computadorizada por Raios X , Dosimetria Fotográfica/métodos , Dosimetria Fotográfica/estatística & dados numéricos , Humanos , Imagens de Fantasmas , Radiometria/instrumentação , Radiometria/estatística & dados numéricos , Dosimetria Termoluminescente/métodos , Dosimetria Termoluminescente/estatística & dados numéricos , Filme para Raios XRESUMO
During a lung computed tomography (CT) examination, breast and nearby radiosensitive organs are unnecessarily irradiated because they are in the path of the primary beam. The purpose of this paper is to determine the absorbed dose in breast and nearby organs for unshielded and shielded exposures with bismuth. The experiment was done with a female anthropomorphic phantom undergoing a typical thoracic CT scan, with TLD-100 thermoluminescent detectors insert at breast, lung and thyroid positions. Results showed that dose reduction due to bismuth shielding was approximately 30% and 50% for breast and thyroid, respectively; however, the influence of the bismuth on the image quality needs to be considered.
Assuntos
Absorção de Radiação/fisiologia , Bismuto/química , Mama/fisiologia , Exposição à Radiação/análise , Proteção Radiológica/instrumentação , Radiografia Torácica/métodos , Tomografia Computadorizada por Raios X/métodos , Mama/efeitos da radiação , Desenho de Equipamento , Feminino , Humanos , Órgãos em Risco/efeitos da radiação , Imagens de Fantasmas , Doses de Radiação , Proteção Radiológica/métodosRESUMO
A new regulatory statement was issued concerning the eye lens radiation protection of persons in planned exposures. A debate was raised on the adequacy of the dosimetric quantity and on its method of measurement. The aim of this work was to establish the individual monitoring procedure with the EYE-D™ holder and a MCP-N LiF:Mg,Cu,P thermoluminescent chip detector for measuring the personal dose equivalent Hp(3) in workers of a Positron Emission Tomography Radiopharmaceutical Production Facility.
