Desenvolvimento de objeto simulador antropomórfico de cabeça com dolomita e metilmetacrilato para dosimetria em tomografia computadorizada

• Ano de defesa: 2016
• Autor(a) principal: Ximenes Filho, Raimundo Erivan Morais
• Orientador(a): Maia, Ana Figueiredo
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Sergipe
• Programa de Pós-Graduação: Pós-Graduação em Física
• País: Brasil
• Palavras-chave em Português: Física; Física médica; Radiologia; Tomografia computadorizada; Radiação (dosimetria); Simulação (computadores); Dolomita; Metilmetacrilato
• Palavras-chave em Inglês: Physics; Medical Physics; Radiology
• Área do conhecimento CNPq: CIENCIAS EXATAS E DA TERRA::FISICA
• Link de acesso: https://ri.ufs.br/handle/riufs/5245

Computed Tomography (CT) is a modality of radiodiagnostic that represents only 15% of the medical procedures performed in this field, nonetheless, this technique contributes with 50% of the collective dose. Procedures that delivers high doses, such as CT, need to be administered under a strict protocol of quality control (QC), because there will always be risks to the health of the patients when they are submitted to high dose exams. From this scenario, the necessity of evaluate the parameters of the X ray beam which the patient is rising; one of the main parameters to be monitored is the dose delivered by the CT exam. It is impossible to perform QC tests in a patient, that is why objects that simulates the attenuation profile of some part of the human body are used. In this specific research, the goal was the construction of a human head phantom. This phantom were built from easy access materials with the goal to be more financially advantageous to use it than its internationals competitors, hence it was spent only U$ 160.00 on its construction. International phantom prices can be more than U$ 4,600.00. Among the analyzed materials in this research, dolomite and polymethyl methacrylate (PMMA) were chose to manufacture the phantom, due its measurements of linear attenuation coefficients (m/) in different proportions, it was decided that dolomite and PMMA in a 1:1 proportion attenuates the X ray beam like the reference material (bone). Dosimetric studies were made in the phantom using an ionization chamber. Its results showed that the effective dose estimative in the dolomite phantom is (2.70 + 0.03) mSv and in the CTDI phantom is (3.67 + 0.04) mSv. Effective dose estimatives found in the literature for head computed tomography exams are in the range of 0.9 – 4.0 mSv. Effective dose measured with the phantom developed in this research are within this range.