北京生物醫(yī)學(xué)工程

C形臂X光機(jī)的原位投影增強(qiáng)系統(tǒng)

A projection-augmented system for in situ projection for mobile C-arms

作者：邢樹偉丁輝王廣志

單位：清華大學(xué)醫(yī)學(xué)院生物醫(yī)學(xué)工程系（北京 100084）

關(guān)鍵詞：移動C型臂X光機(jī); 投影增強(qiáng); 原位投影; 光路重合; 校正

分類號：R318.6

出版年·卷·期（頁碼）：2019·38·6（551-559）

摘要：

目的移動C型臂X光機(jī)是微創(chuàng)骨科手術(shù)中必不可少的成像設(shè)備。針對當(dāng)前微創(chuàng)骨科手術(shù)需要反復(fù)透視和操作直觀性差的問題，本文提出一個針對移動C型臂X光機(jī)的原位投影增強(qiáng)系統(tǒng)。方法首先設(shè)計了一種雙重反射的投影增強(qiáng)模塊；然后基于上述模塊，提出一種基于動態(tài)追蹤的系統(tǒng)標(biāo)定方法，以實(shí)現(xiàn)投影光路與X射線光路重合；接下來利用圖像的單應(yīng)性變換關(guān)系，分別對投影模塊與X射線成像模型間的幾何模型偏差和系統(tǒng)殘留偏差進(jìn)行校正，進(jìn)而優(yōu)化系統(tǒng)投影精度；最后構(gòu)建原型系統(tǒng)，測試了系統(tǒng)性能并設(shè)計腰椎體膜和豬腿脛骨實(shí)驗(yàn)進(jìn)行驗(yàn)證。結(jié)果在精度驗(yàn)證模體距影像探測器不同高度下，系統(tǒng)投影誤差為；固定驗(yàn)證模體，在移動C型臂X光機(jī)不同擺放角度下，系統(tǒng)投影誤差為。腰椎體膜和豬腿脛骨模體實(shí)驗(yàn)表明，可直接在患者體表觀察到患者骨骼等結(jié)構(gòu)的投影信息。結(jié)論本文提出的移動C型臂X光機(jī)投影增強(qiáng)系統(tǒng)，能夠原位投射患者透視影像，直觀地輔助醫(yī)生術(shù)中操作，減少了術(shù)中反復(fù)透視獲取手術(shù)工具和患者內(nèi)部結(jié)構(gòu)位置關(guān)系的次數(shù)，顯示出系統(tǒng)未來臨床應(yīng)用的可行性。

Objective The mobile C-arm is an essential imaging device in minimally invasive orthopedic surgery. To reduce radiation exposure from frequently capturing X-ray images and improve unintuitive operations, we proposed a projection-augmented system for in situ projection for mobile C-arms. Methods First, we design a double projection projection-augmented module. Second, we propose a calibration method based on dynamic tracking to realize the alignment of X-ray and projection light. Third, the geometric model deviation and system residual deviation between the projection module and the X-ray imaging model are corrected by using the homography to improve projection accuracy. Finally, a prototype of the system was constructed, and performance tests and experiments of spine phantom and swine tibia were performed. Results The system overlay error is at different heights from image intensifier to experiment phantom, and is at different rotation angles of mobile C-arms. The experiments of spine phantom and swine tibia show that we can intuitively observe the projection information such as bone structure on the patients’ body surface. Conclusions The proposed projection-augmented system can project X-ray images onto patients in situ, and surgeons can perform intuitive operations and reduce X-ray radiation exposure. Furthermore, we verify the feasibility of our system by phantom experiments.

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