利用雙能量電腦斷層之降低輻射劑量方式應用於大腸直腸癌與腎臟及泌尿道疾病之診斷及評估影像品質與輻射劑量之減少

Low Radiation Dose Protocols for Colorectal Cancer, Renal and Urinary System Diseases using Dual-Energy CT: Image Quality, Diagnostic Accuracy, and Dose Reduction

陳巧雲(Chiao-Yun Chen)

指導教授 ： 劉金昌 ； 鄭添祿

共同指導教授 ： 吳登強 ； 李建宏(Chien-Hung Lee)

高雄醫學大學/醫學院/醫學研究所博士班/博士(2017年)

摘要

電腦斷層掃描(computed tomography, CT)對於協助疾病之臨床診斷日益重要。隨著使用率不斷上升，因電腦斷層檢查對於患者所帶來的輻射劑量，近年也受到大家的重視。為此電腦斷層掃描儀的技術不斷的改進，研發影像重建技術，以提高影像品質與降低患者劑量。當然，減少掃描次數，更能立即減少患者所接受的輻射劑量。
雙源雙能電腦斷層[Dual-source dual-energy computed tomography (DS DECT) ]之雙管球開啟不同射源(高、低 射源)的「雙能掃描」，由於身體組織對不同能量X光射線所對應的衰減值不同，例如：碘(顯影劑的主要成分)在低能源(80 kVp)的最大衰減係數(CT密度)大約是在高能(140kVp)掃瞄的一半。利用雙能 (通常是140kVp與80kVp)掃描，產生的兩個不同X光射線衰減級別係數的數據集，經電腦運算，來分類掃描組織的特性，進行對物質成分之分析，可提供不同的組織區辨，具備區分物質成份的基本能力，目前已知具備可以區別骨頭內含有鈣成分、血管內含有碘成分、尿路尿酸成分的結石及軟組織之顯影。
影像疊代重建法(Sinogram affirmed iterative reconstruction, SAFIRE)為最新研發由原始資料(raw data)端進行反覆運算影像重建技術，藉由校正部分投影計算的變動，快速的降低影像之雜訊與假影，藉由提高影像品質的方法，達到降低輻射劑量的目的。
本計畫著重於研究利用雙能量電腦斷層之降低輻射劑量方式,合併影像疊代重建法(Sinogram affirmed iterative reconstruction, SAFIRE) ,應用於大腸直腸癌與腎臟及泌尿道疾病之診斷及評估影像品質與輻射劑量之降低。

關鍵字

大腸直腸癌 ； 腎臟疾病 ； 泌尿道疾病 ； 雙能電腦斷層 ； 影像疊代重建法 ； 輻射劑量 ； 分段注射 ； 電腦斷層尿路造影

並列摘要

Computed tomography (CT) has recently become the single largest source of medical radiation delivered to the general population. The large number of patients receiving CT examinations has raised concerns regarding radiation exposure of patients, the risk of radiation-induced cancers, and increased cancer deaths later in life. In response to this concern, calls have been made for developing new CT protocols to reduce radiation dose while maintaining an optimal image. Of course, reducing the number of scans, more immediately to reduce the radiation dose received by the patient
With recent advances in CT technology, dual-energy computed tomography (DECT) simultaneously acquires datasets at two different photon spectra (typically 140kVp and 80kVp) in a single acquisition, and iodine (the main component of contrast medium) can be distinguished from other materials owing to its stronger photoelectric absorption at low tube voltages near K-edge of iodine. Using dual-energy scanning, X-rays of two different levels of attenuation coefficient generated data set, the computer operator to scan tissue classification characteristic analysis performed on the material composition can be provided in different tissues distinction, have the ability to distinguish between the basic composition of a substance, now known to have the calcium content of the bones can be distinguished component, intravascular contain iodine ingredients, uric acid ingredients of the urinary stones and enhancement of the soft tissue.
Iterative image reconstruction method (Sinogram affirmed iterative reconstruction, SAFIRE) is a recent reconstruction algorithm, uses a noise modeling technique supported by raw data (sinogram data), to reduce noise and maintain image sharpness. The rapid reduction of noise and artifact images can improve image quality which can achieve the purpose of reducing the radiation dose.
The project focuses of the study are using the dose reduction techniques of dual-energy CT, combined with image reconstruction (Sinogram affirmed iterative reconstruction, SAFIRE), for the diagnosis of colorectal cancer and kidney and urinary tract disease, image quality assessment and evaluation of radiation dose reduction.

並列關鍵字

colorectal cancer ； kidney diseases ； urinary tract diseases ； dual-energy computed tomography ； imaging iterative reconstruction ； SAFIRE ； radiation dose ； split bolus ； CT urography

參考文獻

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