| 摘要: | 隨著植體技術發展，其植入手術已由牙科植體推廣至截肢植體，而手術成功與否則由骨整合 (植體穩固度) 的好壞作為判斷的依據。柱狀植體植入骨骼一般視為懸臂樑結構，當骨整合情況越好，其整體結構剛性越強，共振頻率上升；反之，則下降。本研究開發基於樹梅派之植體骨整合檢測裝置，相較於以工業電腦進行資料處理，具有小體積及可手持等優點，以Osstell?生產的標準結構物Testpeg?、及依據肢體植入手術設計之骨整合模型進行驗證，藉由裝置提供客觀量化數值，來建立骨整合評估方式，與先前以商用資料擷取卡及工業電腦結果做比較。
透過檢測裝置將交流掃頻訊號輸入至電感，使之與植體上端永久磁鐵產生交互變化的磁力激振結構物，由探頭偵測磁通量變化，再經由頻率響應函數計算獲得該懸臂樑結構的共振頻率，藉此評估骨整合狀況。研究中比較兩類探頭對相同結構的評估特性，分別為(1)雙電感對型、(2)雙電感-霍爾IC型，兩類探頭差異在於偵測磁場變化之元件，雙電感對型以第二電感透過法拉第定律將磁場變化轉換為電訊號輸出；雙電感-霍爾IC型則以霍爾IC透過霍爾效應將磁場變化轉換為電訊號輸出。
研究中比較兩種探頭之靈敏度、激振源與待測物距離及響應範圍 等，雙電感對型探頭靈敏度在同磁場強度下會隨訊號頻率而變，1 kHz時為2.8mV/G、10 kHz時為24.5 mV/G；而雙電感-霍爾IC型探頭在各頻率下皆維持1.5 mV/G，總體而言雙電感對型靈敏度較雙電感-霍爾IC型佳。
雙電感對型探頭對於待測結構物磁場強度並無限制，而雙電感-霍爾IC型探頭則須確認霍爾IC量測範圍，以本研究為例，所使用霍爾IC的量測範圍最大為±1000高斯，超出此範圍即無法正確響應磁場變化。
比較激振源與待測物距離，雙電感對型探頭為4.2mm；雙電感-霍爾IC型探頭則為2.5 mm，由頻率響應函數落差點的幅值比較，雙電感-霍爾IC型探頭在不同結構物上幅值皆大於雙電感對型探頭10倍以上，說明雙電感-霍爾IC型探頭的激振能力較佳。
綜合以上比較，雙電感對型在量測磁場範圍以及靈敏度上優於雙電感-霍爾IC型，但激振能力則以雙電感-霍爾IC型優於雙電感對型。
兩類探頭對於Testpeg?皆能量測其共振頻率，其中以雙電感-霍爾IC型量測效果較佳。在山羊股骨截肢模型方面，雙電感-霍爾IC型因待測物上配件的永久磁鐵磁場強度超過量測範圍，以致無法檢測評估；僅雙電感對型探頭能量測截肢模型共振頻率，其檢測結果也能夠反應剛性愈大(表示骨整合越完全)的介面組織，具有越高共振頻率值。
本研究所做基於樹梅派之檢測裝置，名片大小的樹梅派大幅減少檢測裝置體積，雖在抗雜訊及解析度方面不如已發產成熟的商用訊號擷取卡，但亦能透過使用者介面能顯示頻率響應圖及共振頻率，方便攜帶使用。訂定裝置輸入訊號為電壓3 V、1-10 kHz掃頻訊號以及量測距離為1 mm。可量測在6000Hz以下Testpeg?之共振頻率變化；在肢體骨整合模型上因解析度過低無法正確顯示共振頻率。
;With the development of osseointegration of implants, implant placement has been extended from dental implants to amputation implants, and the success of the surgery is judged by the osseointegration (stability of the implant).
When implants are placed in bone, they are considered as cantilever beam structures. The better the osseointegration, the stronger the rigidity, and the higher the resonance frequency; on the contrary, the lower the resonance frequency. In this study, we developed a Raspberry Pi-based implant osseointegration detection device, which has the advantages of small size and handheld type. Validation was performed using the standard structure Testpeg? manufactured by Osstell? and an osseointegration model designed for limb implant surgery. The device provided objective and quantitative values to establish an osseointegration assessment method compared to previous commercial data acquisition cards and industrial computer results.
Through the detection device, the AC sweeping signal is input to the inductor, which generates alternating magnetic field excitating the structure. The resonance frequency of the cantilever beam structure was calculated from the frequency response function by the probe detecting the magnetic force change. Two types of probes were used to measure the same structure: (1) dual inductor pair type and (2) dual inductor-Hall IC type. The difference between two probes lies in the components for detecting the magnetic field change, the dual inductor pair type converts the magnetic field change into telecommunication signal output through Faraday′s law; the dual inductor-Hall IC type converts the magnetic field change into telecommunication signal output through Hall effect.
The sensitivity of the two types of probes, the distance between the excitation source and the structure to be assessed, and the response range were compared, the sensitivity of the dual inductor pair probe varies with the signal frequency at the same magnetic field, from 2 .8mV/G at 1 kHz to 24.5 mV/G at 10 kHz. The dual inductor-Hall IC probe maintains 1.5 mV/G at all frequencies, and overall the dual inductor pair type has better sensitivity than the dual inductor-Hall IC type.
The dual inductor pair type probe has no limitation on the magnetic field strength of the structure to be measured, while the dual inductor-Hall IC type probe requires confirmation of the Hall IC measurement range. For example, in this study, the measurement range is ±1000 Gauss, beyond which the magnetic field change cannot be correctly responded to.
Comparing the distance between the excitation source and the structure to be assessed, the dual inductor pair type probe is 4.2 mm; the dual inductor-Hall IC type probe is 2.5 mm, and comparing the peak-valley differences of the frequency response function drop point, the amplitude of the dual inductor-Hall IC type probe on different structures is greater than the dual inductor pair type probe by more than 10 times, which proves that the dual inductor-Hall IC type probe has better excitation capability.
In summary, the dual inductor-Hall IC type was superior to the dual inductor-Hall IC type in terms of magnetic field range and sensitivity, but the dual inductor-Hall IC type was superior to the dual inductor pair in terms of excitation capability. Both types of probes can measure the resonant frequency in Testpeg?, among which the dual inductor-Hall IC type is more effective. In the goat femoral amputation model, the dual inductance-Hall IC type could not be measured because the magnetic field strength of the permanent magnet on the structure to be assessed exceeded the measurement range. Only the dual inductor pair type can measure the resonance frequency, and the results can fully reflect the harder interface tissue (better osseointegration) with higher resonance frequency values.
The business card-sized Raspberry pi device reduces the size of the device and displays the frequency response graph and resonance frequency through the user interface, making it easy to carry and use. The input signal of the device is set at 3 V, 1-10 kHz sweep signal and the measurement distance is 1 mm.
The resonance frequency of Testpeg? can be measured below 6000Hz, the resonance frequency cannot be displayed correctly on the limb osseointegration model due to the low resolution. |
