陳永耀臺灣大學：電機工程學研究所李岳儒Li, Yue - RuYue - RuLi2007-11-262018-07-062007-11-262018-07-062007http://ntur.lib.ntu.edu.tw//handle/246246/52998本研究的目標為建立一個追蹤系統，並設計一套演算法，將海扶刀（HIFU，高能聚焦超音波加熱系統）應用於肝臟腫瘤熱治療。研究中使用CCD攝影機模擬核磁共振醫學影像系統（MRI），進行移動中仿體的取像。仿體放置於一個可程式化的馬達平台上，此平台用來模擬受呼吸影響的肝臟運動狀態。研究中也設計了一套類神經網路的演算法，接受訓練後用來預測移動平台移動中的位置。並下達指令予追蹤平台來追蹤仿體的軌跡，即肝臟的運動。在追蹤的同時，使用陣列式超音波換能器傳遞能量來加熱目標。此超音波換能器以多頻道功率放大系統驅動。研究中將提出模擬以及實驗的結果來說明此追蹤系統和預測演算法在追蹤仿體運動以及熱治療上是可行的。因此，這些結果指出此追蹤系統應用在以MRI為影像導引的海扶加熱系統上能即時地追蹤加熱受呼吸運動影響的肝腫瘤。The purpose of this research is to build a tracking system and algorithm with high intensity focus ultrasound heating system to do liver thermal therapy. In this study, a CCD camera was used to simulate MRI medical image system, and to take series of image of a moving phantom driven by a programmed motor. The programmed motor was used to simulate liver motion affected by breathing. Then a neural-network algorithm was designed and trained to fit and predict the position of programmed motor and to control the tracking motor to track the phantom motion trajectory, liver motion. The predicted position information was sent to the tracking motor to drive an ultrasound phased array transducer to an appropriate position to deliver acoustic power to heat the target precisely. The ultrasound transducer is driven by a multi-channel power amplifier system. There will be some simulations and experimental results which illustrate that CCD guided focused ultrasound system was able to track the phantom motion and then to heat the target region to do the thermal therapy. The results indicated that when the tracking algorithm was applied on a MR imaging guided HIFU (High Intensity Focus ultrasound) heating system it was able to do a real time motion-tracking thermal therapy for liver tumors affected by the respiratory motion.口試委員會審定書----------------------------- i 誌謝----- -------------------------------------ii 中 文 摘 要---------------------------------- iii Abstract------------------- -------------------iv Contents------------------- --------------------v List of Figures------------ --------------------vii List of Tables------------- --------------------xi List of Tables------------- --------------------xi Chapter 1 Introduction----- ---------------------1 1.1 Introduction------ ---------------------1 1.2 Motivation & Problem Statement---------------3 1.3 HIFU System----------------------------------7 Chapter 2 System Structure-----------------------10 2.1 HIFU Carrier and Tracking Platform 1---------11 2.2 Color-Changeable Phantom and Carrier---------13 2.3 Liver Tumor Motion Platform 2----------------15 2.4 Image Catching System by CCD-----------------19 2.5 Prediction Algorithm on PC-------------------20 2.6 Heating System -------------------------------21 2.7 System for Analyzing Tracking Error----------24 Chapter 3 Predicting Algorithm-------------------27 3.1 Introduction to Neural Network---------------27 3.1.1 Introduction of Basic Neuron---------------27 3.1.2 Introduction of Basic Neural-Network-------29 3.1.3 Mathematical Model of Neuron---------------30 3.2 Structure of Prediction Algorithm------------32 Chapter 4 Introduction of Linear Scale-----------38 4.1 Working Principle----------------------------38 4.1.1 Right or Left Decision of Linear Scale-----42 4.1.2 Distance Counter---------------------------45 4.2 Hardware Measurement-------------------------46 4.3 LabVIEW Program------------------------------48 4.3.1 Sampling Data from DAQ Card----------------49 4.3.2 Transfer Voltage Value to Digital Signal 0, 1-50 4.3.3 Adjust the Order of Data-------------------51 4.3.4 Simplify the Repeated State.---------------52 4.3.5 Calculate the Position---------------------53 4.3.6 Plot the Trajectory of Platform------------59 4.3.7 Calculate the Tracking Error---------------60 4.3.8 Save the File------------------------------62 4.4 Virtual Instruments of Linear Scale----------63 4.5 Test of Linear Scale-------------------------67 Chapter 5 Experiment and Result------------------69 5.1 Production of Color-changeable Phantom & Measurement of Characteristics……………..………………………………………………..70 5.1.1Production of Color-changeable Phantom-------70 5.1.2 Measurement of Characteristics--------------71 5.2 Procedure of Continuously Tracking HIFU Experiment---76 5.3 Simulation-------------------------------------------80 5.3.1 Simulation Results --- Different Amp---------80 5.3.2 Simulation Results --- Different Period------85 5.3.3 Simulation Results --- Amp + Period----------90 5.3.4 Simulation Results --- Regular---------------95 5.4. Experiment --- Heating Results----------------100 5.4.1 40W × 25 sec---------------------------------101 5.4.2 50W × 20sec----------------------------------104 Chapter 6 Discussion-------------------------------107 6.1 Correction of Historical Data------------------107 6.2 Comparison of Fixed Heating and Tracking Heating---110 Chapter 7 Conclusion-------------------------------115 Reference ------------------------------------------1173242188 bytesapplication/pdfen-US海扶刀熱治療肝腫瘤類神經網路光學尺HIFUThermal therapyLiver tumorsNeural-networkLinear scalethesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/52998/1/ntu-96-R94921011-1.pdf