利用田口方法最佳化錐形射束電腦斷層影像之品質特性

Optimizing the Cone Beam Computed Tomography Image Quality Characteristics by the Taguchi Methodology

蕭貴仁(Kuei-Jen Hsiao) ； 陳俊吉(Chun-Chi Chen) ； 潘榕光(Lung-Kwang Pan)

《中華放射線技術學雜誌》 38卷4期 (2014/12) Pp. 213-219

摘要

本研究目的是利用田口方法最佳化錐型射束電腦斷層的設定以提高影像的品質特性。目前放射治療的驗證技術以錐形射束電腦斷層影像為主流，而本院目前是採用原廠給予的條件造影，本實驗是利用自製的水箱假體與V型假體模擬腹部定位之情形，藉由重覆三次的實驗以找出再最佳影像品質之特性條件組合，並利用Catphan 600中的CTP528模組加以驗證其臨床的合用性，最後再與原廠設定值的參數比較。由田口最佳化分析後發現最佳化的參數組合，投射量數目為720、像素數目則是384x384、切片厚度為2.5mm而重組濾片設定為smooth。該組合能夠將影像的再現性的標準差由0.076 cm降低為0.010 cm，雖然影像解析度稍微降低了0.5mm，但降低的程度遠小於機械性的誤差，並不影響臨床上的使用。

關鍵字

錐形射束電腦斷層 ； 田口最佳化法 ； 再現性

並列摘要

The aim of this study is to optimize the image quality characteristics of Cone Beam Computed Tomography (CBCT) through the Taguchi L_8 (2^7) analysis. CBCT is the mainstream of the technique to verify the imaging quality in radiation oncology. The hospital where r work for adopts the original grant conditions in verifying the acquired image, whereasaself-made water tank and a V-shape phantom were designed to optimize the abdomen scanning protocol in routine survey. Each orthogonal array that was recommended by Taguchi was repeated three times for ensuring the reproducibility to optimize the quality characteristics of scanned image, and then was verified by adopting the CTP528 modulus of catphanmodel 600. The optimized recommendation was A (No. of Projection) 720, B (No. of pixel) 384x384, C (Slice thickness)2.5 mm, and D (Reconstruction filter)smooth . The standard deviation of the analyzed image quality was decreased from 0.076 cm to 0.010 cm for the optimal setting. The deviation of spatial resolution was slightly extended to 0.5 mm, more than that was obtained from the original default. However, it barely affected the routine maintenance since the mechanical tolerance was set 2 mm.

並列關鍵字

CBCT ； Taguchi method ； Image reproducibility