Estudo da Viabilidade de Otimização dos Protocolos Pediátricos em Exames de Tomografia Computadorizada de Crânio

Abstract

Computed tomography (CT) is a method of diagnostic imaging with high doses of ionizing radiation delivered to the patient – from 100 to 500 times than the doses in conventional x-rays procedures. In the case of pediatric patients, the concern with radiation doses is greater, due to the long life expectancy and the fact that they are more radiosensitive than adults. Therefore, it was decided to carry out the study with pediatric patients, from 0 to 2 years old, who underwent cranial CT exams. The objective of this work is to present the evaluation of a process of optimization of pediatric skull protocols in computed tomography, evaluating parameters of image quality and dose reduction, without loss of image quality. The CTDI_vol index was verified in fifteen samples of skull exams, as well as image acquisition parameters, in the referred protocol. From these data, five experimental protocols were developed and the contrast-noise ratios of the images produced were analyzed. Using the figure of method (FOM) as a quality metric for quality analysis in comparison with CTDI_vol levels, it was concluded that, although the dose index of the current protocol is consistent with the AAPM recommendation, of 29 mGy, it is possible to reduce the CTDI_vol index to 18 mGy - that is, a 40% reduction in CTDI_vol in relation to the AAPM recommendation and 23% in relation to the current protocol. With the acquisition parameters studied, a reduction in the quality of the images was found, according to the FOM analysis. Therefore, it is suggested to use noise reduction algorithms, that is, reconstruction filters, so as not to impair the diagnostic quality of the images.