RESUMO
In this article, we report on the development of a simple and accurate method for quality assurance of electron beam output and energy. Aluminum disks of thicknesses d(max) or d50 of the particular electron energy are positioned sequentially over a parallel-plate ion chamber and the ratio of the two signals is compared to the standard. The positioning of the aluminum disks is carried out remotely and automatically to eliminate the necessity of multiple setups. One method utilizes the remote control feature of the treatment couch and another employs a motor-driven carousel. The superior sensitivity over a commercially available energy monitor is illustrated.
Assuntos
Aceleradores de Partículas/instrumentação , Aceleradores de Partículas/normas , Garantia da Qualidade dos Cuidados de Saúde/métodos , Radiometria/instrumentação , Radiometria/normas , Radioterapia/instrumentação , Radioterapia/normas , Canadá , Elétrons , Desenho de Equipamento , Análise de Falha de Equipamento , Transferência Linear de Energia , Garantia da Qualidade dos Cuidados de Saúde/normas , Doses de Radiação , Radiometria/métodos , Radioterapia/métodos , Padrões de Referência , Robótica/instrumentação , Robótica/métodos , Robótica/normasRESUMO
Some linac manufacturers provide cones for defining circular electron fields. During commissioning of one of our new radiotherapy units, we noted that the output of these cones has a strong dependence on the diaphragm opening that precedes the cone. In particular, for the 8 MeV beam, the output of a 3 cm diameter cone increased by more than a factor of 2 as the diaphragm was opened from 5 x 5 to 20 x 20 cm. One concludes that the particular mechanical design results in an output factor dependency that is exceptional when compared to the data presented in standard texts such as Khan's "The Physics of Radiation Therapy." The importance of quality assurance and communications with the manufacturer is underscored by this example.
Assuntos
Elétrons/uso terapêutico , Radioterapia de Alta Energia/instrumentação , Desenho de Equipamento , Aceleradores de Partículas , Controle de Qualidade , Radioterapia de Alta Energia/métodos , Radioterapia de Alta Energia/normasRESUMO
Contenido: Cap.1 Generalidades sobre instalaciones de bombeo mecanico.Equipo superficial.Equipo subsuperficial.Equipo auxiliar.Enfoque de los problemas en pozos de bombeo mecanico Cap.2 El dinamometro.Generalidades.Tipos de dinamometros.Carta dinamometrica.Obtencion de las cartas Cap.3 Interpretacion de las cartas dinamometricas.Sistema ideal.Cargas basicas.Determinacion del torque instantaneo.Curva desplazamiento del vastago Vs tiempo.Problemas tipicos.Ejemplos Cap.4 Aplicacion practica en el campo Tatarenda.Diseño de una instalacion de bombeo.Cuadro comparativo.Analisis dinamometrico pozo TTR-49.Conclusiones.Recomendaciones.Problemas tipicos del bombeo mecanico en TTR Cap.5 Analisis de los costos.Costos de operacion.Conclusiones y recomendaciones.