Browsing by Author "Costa, D. M."
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- Comparison between 3D laser scanning and computed tomography on the modelling of head surfacePublication . Sousa, Eva; Vieira, Lina; Costa, D. M.; Costa, Durval C.; Parafita, R.; Loja, M. A.The measurement of people physical parameters and proportions constitutes an important field of science, the anthropometry since it is related to the characterization of the human size and constitution; it allows improving the design and sizing of systems and devices to human use. To enable these measurements, different direct and indirect methodologies may be used depending on the particular aim of a specific study and on the eventual availability of data sources that can be used also for this purpose. Because of this relevance, the present work intends to assess the influence of different acquisition and reconstruction methods in the modeling of a 3D head surface. In order to assess the significance of the differences between acquisition and reconstruction methods, a set of measurements between several anatomic references of a physical phantom were carried out. Statistical evaluation using the Friedman test for non-parametrical pared samples was considered. We found, so far, no statistically significant differences between the several methods considered for acquisition and reconstruction.
- Using 3D anthropometric data for the modelling of customised head immobilisation masksPublication . Loja, MAR; Sousa, Eva; Vieira, Lina Oliveira; Costa, D. M.; Craveiro, D. S.; Parafita, R.; Costa, D. C.Head immobilization thermoplastic masks for radiotherapy purposes involve a distressful modeling procedure for the patient. To assess the possibility of using different acquisition and reconstruction methods to obtain a 3D skin surface model of PIXY-phantom-head and to present a proposal of an alternative head immobilization mask prototype. Phantom head geometry acquisitions using: computed tomography (reconstructed with ImageJ and Osirix); and 3D Laser Scanner (reconstructed with SolidWorks). From these reconstructed surface models, a set of landmarks was measured and subsequently compared with physical measurements obtained with a Rosscraft-Calliper. For statistical evaluation, relative deviations graphics and Friedman-test for non-parametrical paired samples were used, with a significance level of 5%. For a first assessment of the proposed mask performance, a radiotransparent material was considered, the strength and stiffness evaluation is performed using the finite element method. There are small differences between all the acquisitions and reconstructions methods and the physical measurements, statistically significant differences (X2F(6)) = 6.863, p=0.334) were not found. The proposed mask performed well from the strength and stiffness perspectives, leading to the desired immobilization aim. The immobilization mask design proposal may be an effective alternative to the present completely hand-made situation, which presents a high degree of discomfort and stress to the patients.