Análises de metodologias de CQ em IMRT de mama, com a técnica de IMRT Flash, no sistema de planejamento PROWESS®

• Autor(a) principal: Santos, Gilmar Batista
• Data de Publicação: 2018
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/12551
• topic: Intensity Modulation Radiation Therapy(IMRT); IMRT Flash technique; Quality Control of IMRT; Breast planning; Radioterapia por Intensidade Modulada (IMRT); Técnica de IMRT Flash; Controle da qualidade de IMRT; Planejamento de mama; Radioterapia; Radioterapia de intensidade modulada; Radioterapia - Controle de qualidade; Mamas - Câncer; CNPQ::ENGENHARIAS::ENGENHARIA NUCLEAR::APLICACOES DE RADIOISOTOPOS

Breast cancer is the most common cancer in women and radiotherapy is usually the recommended treatment. Thus, radiotherapy services with PROWESS® planning system can use the IMRT Flash technique, which is a practical way of planning breast treatment with Intensity-modulation Radiation therapy (IMRT). Nevertheless, in order to release this planning for treatment, it is necessary to measure the dose distribution and to compare it with that of the computerized planning system (Quality Control (QC)). This method requires machine time. The IMRT flash technique modulates only a small portion of the dose (approximately 30%) and most of it is delivered with a conformational field (70%). Thus, it is possible to develop other techniques, simpler to release the treatment, such as: the manual calculation of Monitor Unit (MU). and establish an average value of MU. Therefore, the objective of this study is to propose two new quality control methodologies, in addition to the traditional measurement of the dose distribution with planar device: the manual calculation for 70% of the dose, with an accuracy of ± 5% between the planned dose and the one administered in PTV, and the comparison with the mean value of MU, using a confidence limit of 01 standard deviation. In addition, this study enabled the creation of a Gama criterion and percentage of approval to release the comparison between the measured dose distributions, with 2D planar device, and the Planning System. This study was done in a radiotherapy service in Rio de Janeiro and it was tested in 34 planning cases that correspond to 204 treatment fields. To conclude, the methodology which uses an average value of MU was efficacious in verifying the IMRT Flash technique, as it was validated with 29 planning cases. Furthermore, when combined with manual calculation, it established a quick and efficient barrier of planning analysis. The last methodology, which corresponds to the Gamma criterion, was important to help the radiotherapy service to establish, in breast cases, a Gamma criterion