利用田口方法尋找低劑量腹部電腦斷層最佳參數

目的:低劑量電腦斷層目前在臨床運用是越來越頻繁，而低劑量所帶來的負面影響就是影像品質不好，所以本研究利用田口方法來分析低劑量腹部電腦斷層影像，使用田口方法中L18來設計實驗尋找出最佳的條件參數。方法:利用西門子電腦斷層儀器掃瞄腹部假體，模擬檢查腎結石時的情況，藉由田口方法的18標(L18)設定實驗5個控制因子，控制因子包含:(A)kernel使用Abdomen B30f medium smooth和Bone B60f sharp。(B)kVp:80、100、120。(C)mAs:80、100、120。(D)Slice thickness:3mm、5mm、7mm 。(E)Pitch:0.5、1、1.5。透過直交表會有18組合，總共會有18組影像。評量出低劑量腹部電腦斷層的最佳參數。評估結束後再使用ANOVA來進行最後的分析。結果:田口方法評估出低劑量腹部電腦斷層主要調整因子是Kernel和kVp，最佳的設定條件是Bone B60f sharp的kernel、120 kVp、120 mAs、7 mm的Slice thickness以及1.5 Pitch。討論:kVp和Kernel與各個因子之間並無交互作用關係；mAs不影響影像品質的原因可能是極距太狹隘導致無法比較出差異，另外一點是現在影像後處理的進步，造成低mAs也可以得到較優良的影像品質。

關鍵字

腎結石；田口方法；腹部假體；低劑量腹部電腦斷層

並列摘要

The imaging quality of Reduced-Dose abdominal CT was optimized via Taguchi analysis and an indigenous line group gauge in this study. The reduced-dose CT is an innovated technique in late 2010. It provided a precise image profile without letting patients undergone high dose exposure. However, the preset factor of the CT was still challenged for its potential application in diagnosing the tiny artifact. Thus, a robust designation was proposed herein to optimize the imaging quality of line group gauge inside the phantom’s kidney according to the Taguchi’s L18 recommendation. The Taguchi orthogonal array was gained its reputation in shortening the experimental repetition trials. Five factors of reduced-dose CT defined as (A) kernel, (B) kVp, (C) mAs, (D) slice thickness, and (E) pitch was organized into only eighteen groups for the optimized analysis according to Taguchi’s unique arrangement, In doing so, every factor had either two or three levels to preset, therefore a total of 162 ((2×3×3×3×3=162) combinations were actually considered in this study. the line group gauge was specially customized to fulfill the practical needs in kidney CT diagnosis. The CT scanned images were ranked by three well-trained radiologists on the basis of double-blinded criteria to evaluate the contribution of every factor according to their ranked average, standard deviation and signal to noise ratio, S/N, which was also defined by Taguchi. The optimal recommendation of reduced-dose CT was later confirmed as (A) Bone B60f sharp kernel, (B) 120 kVp, (C) 120 mAs, (D) 7 mm slice thickness, and (E) 1.5 pitch from fish-bone-plot of acquired data, and the followed survey proved the dominant factors were kernel as well as kVp from the ANOVA test.

並列關鍵字

Kidney stones ； Taguchi methodology ； Abdominal Phantom ； Reduced-Dose abdominal CT

參考文獻

1.Naidich DP,Marshall CH,Gribbin C,et al. Low-dose CT of the lungs: preliminary observations.Radiology 1990;175:729-731

Google Scholar

2.Diederich S,Wormanns D,Semik M,et al. Screening for Early Lung Cancer with Low-Dose Spiral CT: Prevalence in 817 Asymptomatic Smokers. DOI：10.1148 / radiol.2223010490

Google Scholar

3.Kaneko M, Eguchi K, Ohmatsu H,et al. Peripheral lung cancer: screening and detection with low-dose spiral CT versus radiography.DOI：10.1148 / radiology.201.3.8939234

Google Scholar

4.Smith RC, Verga M, McCarthy S,et al.Diagnosis of acute flank pain: value of unenhanced helical CT.DOI：10.2214 / ajr.166.1.8571915

Google Scholar

5.Kothari K, Hines JJ.CT Imaging of Emergent Renal Conditions.DOI：10.1053 / j.sult.2017.11.003

Google Scholar

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