Development of a statistical analysis software for respiratory signal evaluation on 4D Tomography

The quality improvement in radiotherapy treatments, from the point of view of increased tumor control and decrease in normal tissue damages led to the creation, among other technologies, of retrospective 4DCT. This technology allows the obtaining of tomographic images related to the respiratory phase, thus creating a 4D tomography. However, the reliability of this imaging modality is directly related to the patient's breath reproductivity. Because of this, the department uses a visual analysis of respiratory signal quality that covers 4 parameters: peak amplitude, valley amplitude, cycle period and point variations. Currently, the analysis process is carried out qualitatively, which generates great divergence between observers and the risk that some problem is not detected. The objective of this work was to create a tool that allows the analysis of quantitative parameters of the measured respiratory signal, to assist in the qualitative analysis of the observers. The data obtained as software output are the mean and standard deviation of the amplitudes of the peaks, the amplitudes of the valleys and the peak and valley periods. The program also generates graphs for visual analysis of parameters. The software allowed the achievement of quantitative characteristics of the patient's breathing during the clinical routine. Adding information that was previously not available to the observer. (author)