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    Small-sized computed tomography system with rotating gantry
    (2010-07-30)
    Jantanayingyong, V.
    ;
    Chanwimalueang, T.
    ;
    Srisuk, N.
    ;
    Pintavirooj, C.
    Small-sized computed tomography system with rotating gantry is presented in this paper. System calibration was performed before achieving the projection data. An object placed on platform was exposed by the x-ray every two degrees of rotating angle. Thus, 180 projection data were performed in this study. Finally, Feldkamp algorithm based on a 3D filtered backprojeciton was employed to reconstruct cross sectional images. The result shows that cross sectional images obtained from small-sized computed tomography were satisfactory. In conclusion, the small-sized computed tomography presented in this study is capable to construct the cross sectional images. Moreover, 3D model reconstructed from these cross sectional images will be performed in the future work.
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    Combined medical imaging with CFD analysis for application of diagnostic and treatment planning: The case study of human nasal airflow simulation based on CT imaging
    (2009-01-01)
    Hemtiwakorn, Khaisang
    ;
    Phoocharoen, Niwat
    ;
    Tungjitkusolmun, Supan
    ;
    Mahasittiwat, Visan
    ;
    Sangworasil, Manas
    The previous methods of human airflow measurement such as rhinomanometry or acoustic rhinometry could not visualize the airflow and calculated the velocity magnitude in specific region of nasal cavity. Thus, this study proposes the combination of CT and CFD analysis of nasal airflow simulation in normal human breathing. This method can demonstrate the airflow direction, and also calculate the velocity magnitude inside the nasal cavity. The processes of this study are segmentation, meshing, solving, and post-processing. Firstly, Mimic 10.01 software was used to segment the nasal cavity. Secondly, Pro-STAR/amm software was used to generate trimmed mesh of 338, 496 elements. Finally, computational grid model was imported to STAR-CD version 3.26 for numerical computation, and visualize the solution by post-processing. The result shows that velocity magnitude of airflow is greatest in nasal valve area which is the narrowest area of the human nose. Also, the flow commonly pass through the main nasal passage and middle meatus areas of nose. Experimental validation will be reported in the further publication. In conclusion, this study is the important begining of an applied CFD analysis with medical imaging. CT imaging combines with CFD analysis could be useful for rhinologist as a nose function evaluation technique. Moreover, the applications of this method could be utilized in a wide range of research topics, especially development of diagnostic and treatment planning techniques.
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    Segmentation of magnetic resonance images using discrete curve evolution and fuzzy clustering
    (2007-12-01)
    Supot, Sookpotharom
    ;
    Thanapong, Chaichana
    ;
    Chuchart, Pintavirooj
    ;
    Manas, Sangworasil
    The region clustering of a Magnetic Resonance Imaging (MRI) image is more complicate than a Computed Topography (CT) image because a MRI image composes of three components such as T1-weighted, T2-weighted, and Proton Density (PD) in each layer. However, the MRI images provide more detail than the CT images. Therefore, we propose a technique of the region clustering of MRI image by using Fuzzy c-means (FCM). The fuzzy c-means algorithm is an iterative operation, that is very time-consuming and makes the algorithm impractical for using in image segmentation. To cope with this problem, the discrete curve evolution (DCE) technique is applied to find the actual cluster center to refine the initial value of the fuzzy c-means algorithm, which reduces the convergence time. In experimental results, the proposed technique provides the same segmentation accuracy as the fuzzy c-means technique. Moreover, this technique takes lower computational time comparing to the previous method. © 2007 IEEE.
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    Miniatured computed tomography system and calibration
    (2006-12-01)
    Pititheerapab, Y.
    ;
    Chanwimalueang, T.
    ;
    Pintavirooj, C.
    ;
    Tosranon, P.
    In this paper, we focus on a miniature computed tomographic system with application in 3D modelling of bony structure of a small animal. Our system consists of an x-ray source, a rotating platform and an x-ray array detector unit. The rotating platform is controlled by a personal computer which can rotate the sitting object to arbitrary angle. The x-ray array detector is used to capture the 2D x-ray signal that traversing the object placed on the platform. The x-ray detector is an image intensifier tube of which the 2D image is coupled to the computer via a CCD camera. Feldkamp Conebeam technique is engaged for reconstructing tomograms due to its simplicity. Volume rendering technique together with the shading effects is performed on a stack of cross-sectional image to realize the data into 3D visualization. The algorithms are applied to the practical situation where a series of x-ray radiographs of an animal's bone are collected from the system. The 3D modelling of such bone is performed on the cross-sectional images reconstructed with Feldkamp Conebeam. The results are very satisfactory. © 2006 IEEE.