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  • 學位論文

利用MATLAB影像處理工具盒重組斷層層析影像對影像診療科的輔助

The Assistance of Tomosynthesis Image Reformation using MATLAB Image Processing Tool-box for Department of Radiology.

指導教授 : 胡威志

摘要


本研究使用斷層層析影像進行診斷或治療的定位輔助,利用電腦斷層ACR認證假體,獲得X光管球擺動角度與相對應斷層層析切層厚度關係的驗證,再利用具有不同X光衰減係數圓柱體的電腦斷層假體,進行灰階線性度比較,也比較不同運算法的重組時間,再將序列影像載入影像處理軟體中進行影像重組與圖像呈現,並計算出像素的大小,以比較圓柱體大小實際值與計算值的差異,最後藉此進行不同成像方向的影像呈現,比較影像輔助效果。數位斷層層析攝影術在平板偵檢器數位式X光機使用與斷層攝影相同的成對原理,單一一次X光暴露,可得到X光暴射範圍內連續切層的斷層影像序列。影像灰階線性度與電腦斷層相似;單一層析影像像素為0.298 mm*0.298 mm;而使用濾波逆投射法重組41張影像比位移與累加法重組快約27秒;使用40度X光管球擺動角度所獲得的斷層層析影像切層厚度為2mm;利用Wilcoxon signed-rank test進行分析,以X光透視或斷層層析的影像進行判定組織與器械相對位置的同意度,P值等於0.0016,顯示相對於傳統二維影像,利用斷層層析攝影影像,更容易獲得診斷或治療部位中器械與組織的相對位置關係。利用重組後影像間距可計算出相對距離。因此,在進行X光透視導引定位的檢查或治療時,利用斷層層析的序列影像顯示,提供影像診療科醫師有關器官或組織與手術器械相對位置的影像資訊,使定位確認更精確。藉由重組斷層層析影像的輔助,讓影像診療科醫師在執行X光透視導引術術中,如皮胃管置入術,能有更精確的空間資訊與縮短手術流程。

並列摘要


This study was using the tomosynthesis technique and the ACR CT accreditation phantom to verify the relationship of the swing angle of x-ray tube and sectional thickness. In addition, the grayscale linearity, the reconstruction time for different algorithm, the calculated volume accuracy, and the effectiveness of images reconstructed along various directions were evaluated. The tomosynthesis technique in flat panel digital X-Ray system uses similar “twinning principle” theory to tomography to produce serial sectional images of human body. The grayscale linearity of reconstructed images was similar to the results from CT images. The pixel size of reconstructed tomosynthesis images was 0.298 mm*0.298 mm. The reconstruction time for 41 images using filtered back projection was 27 seconds faster than shift and add algorithm. The sectional thickness of each tomosynthesis image was able to reach as thin as 2 mm using 40 degrees swing angle of x-ray tube. In the analysis of the agreement of using fluoroscopy or tomosynthesis to identify the relative location between instrument and specific tissue, the result of Wilcoxon signed-rank test, the p-value, was 0.0016. This implies that using tomosynthesis images in localization of instrument in diagnosis and/or treatment was superior to using conventional superimposed images. The relative distance can be calculated from these images. Therefore, during the fluoroscopy guided diagnosis or treatment, this technique provides additional spatial information to the radiologists and improve the accuracy of localization. With the helpful of these images, the radiologist can have more accurate spatial information during fluoroscopy guided procedures, such as percutaneous gastrostomy, and may shorten the process of operation.

參考文獻


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