摘要
本論文設計一胸腔動態位移檢測器，運用反正切相位解調方法來測量呼吸時胸腔起伏之相對位移。惡性腫瘤絕大部分為動態腫瘤，會因呼吸起伏造成腫瘤位置改變。當放射線治療時對腫瘤照射高劑量之X射線，本檢測器能精準量測胸腔動態起伏之位移，透過搭配視覺介面，患者能自主地控制呼吸節奏，使放射線儀器能校正呼吸起伏造成之腫瘤位移，進而精準控制其照射範圍，降低傷害正常組織之風險與副作用。本系統採用雷達回波相位解調原理，利用震盪器產生一2.4 GHz之連續波，透過發射天線發射於胸腔上之標籤電路。標籤電路具有調變機制，可將收到之連續波訊號轉為BPSK調變連續波，回波至接收天線。經由低雜訊放大器(LNA)與正交混頻器(IQ Mixer)將訊號混至基頻，饋至電腦端數據擷取卡(DAQ)，利用LabVIEW軟體進行動態位移演算法，擷取動態位移資訊。 量測時運用線性馬達產生不同量測條件，模擬不同肺活量與呼吸狀態(急促、緩慢、憋氣) 情境。位移為10 cm之大肺活量情境，其急促呼吸、緩慢呼吸、憋氣狀態下之均方根誤差率分別是5.7 %、1.2 %、0.6 %。位移量為5 cm之中肺活量情境，其相異呼吸狀態均方根誤差率為0.8 %、8.0 %、6.1 %。
並列摘要
In this thesis, a chest motion detector was developed by using radar arctangent phase demodulation method. The dynamic tumor changes its location with respiratory chest motion, which will cause X-ray harmful illuminating to the tumor neighboring organs. This detector can accurately measure the chest relative location, which allows the patient to control the respiration rhythm and vital capacity. As a consequence, the radiation control instrument can accurately illuminate the tumor position and diameter to reduce the radiation misalignment side effects. The chest motion detector transmits a 2.4 GHz continuous wave to the tag on the chest. The tag scatters the impinging continuous-wave with BPSK modulation for clutter suppression. The received BPSK-modulated signal is then filtered, amplified and down-converted to the basedband for the data acquisition by DAQ card. Finally, the dynamic displacement information is retrieved by zero-crossing and proportional estimation algorithms. Various scenarios were set up to measure the chest motion under different respiratory status (Tachypnea, Bradypnea, suffocate). For the large vital capacity of 10 cm chest displacement, the root-mean-squared errors are 5.7 %, 1.2 %, 0.6 % for tachypnea, bradypnea, suffocate condition, respectively. For the small vital capacity of 5 cm chest displacement, the root-mean-squared errors are 0.8 %, 8.0 %, 6.1 % for tachypnea, bradypnea, suffocate condition, respectively.