體積估測應用於乳癌術後乳房之重建

Abstract

乳癌是台灣也是全世界女性非常普遍的癌症。對女性而言，乳房是重要的性別象徵，乳房重建可以明顯減少乳房切除後患者的心理創傷。最近由於早期診斷及癌症治療方式的進步，存活率已有明顯提高，加上好發年齡的下降，勢必有更多的女性在乳房切除後須加以重建。滿意的乳房重建並非易事，為了同時配合術後癌症輔助療法的需求，才會有外來物植入或自己的組織重建等種種術式的結合，不過不論何種方法，病人最基本的要求便是兩側乳房要對稱，雖然有多種因素決定最後乳房的大小與形狀，若術前沒有好好評估，尤其是體積的估測，以作為重建乳房要達到的目標，如何能達到對稱呢？ 在此實驗，我們將改裝過的雕刻模擬機(PHAToM)當作三度空間的定位儀，可在女性病人胸前薄衣上定位取點，將這些點重建成多平面的網，再重建成胸部之模型，將來建立好資料庫後，我們便能以更少的點，重建胸部模型並計算其體積，這改裝過的設備不但便宜、使用方便，更能被病人及使用者接受。我們用此儀器檢驗三十位乳房重建的病人，發現它最適用於延遲重建的病人，此時因重建部位的乳房已切除，只剩對側乳房當作參考，故術前體積估測能大大的幫助決定使用的義乳或自體組織的量。另一用途為在使用義乳立即重建的病人，此時雖有切下來的乳房當參考，但因其值會因肥胖、脂肪切除較多或腋下淋巴組織一併切除而差異很大，當決定使用何種大小的義乳時，術前體積的估算能大大提高大小適當的可能性，主要是因義乳太貴，一旦打開發現不適當就報銷了，故一次只能開一個。但在用自體組織立即重建時，因可一部份一部份切除過多的組織，有沒有術前估計值就較不重要，但仍可加速一次到位。 雖然有很多因素影響乳房重建最後的結果，如脂肪組織因缺血而壞死、水腫或兩側乳房不對稱等因素，若能用這3D影像工具追蹤比較重建的乳房，除了將來能幫助設計對側乳房之增大或縮小外，才能找到達到對稱的訣竅或是規則，不至於讓乳房重建永遠是一種藝術，而是一門科學。

Breast cancer is the most common cancer among women in the world and also in Taiwan. All breast cancer treatment has the potential to adversely affect breast appearance and cause morbidity due to deformity. Reconstructive breast surgery has proved to be beneficial for the development of psychological outcome and self-image. While the decrease in death rates from female breast and higher incidence in younger women, we can expect there will be more breast cancer patients in need of reconstruction. Without sound information management and refinement in our total management of breast cancer which includes sound reconstruction, we will be out of competition. Since symmetry is the first priority patients ask for, we should first create long-term equal volume of breast by careful preoperative planning which should include 3D volume estimation and then use this volume and 3D imaging device to monitor the development of reconstructed breasts. In this thesis, we described a novel method for constructing 3D human breast models with only some sample points which are captured by using a manual remodeled probing device. We first manually remodel a robot-arm-like device to be a probing device and calibrate it to have a reasonable precision. Then, we capture some sample points on a real human breast and use the sampled points to construct the 3D breast model. For further uses, the constructed 3D breast models are re-meshed to be consistent models. The main purpose of this method is not only to provide a cheaper method than using a 3D scanner but also to keep the patients’ privacy while capturing the breast data. By using our method, the patients can still wear their underwear or a thin robe, and are not necessarily stark-naked. Volume estimation by this 3D imaging device is easy, efficient and acceptable for both patients and the personnel using it. It was most useful when there was no other reference (such as breast specimen weight) except the opposite intact breast in delayed reconstruction cases. It is still very useful in immediate reconstruction when prosthesis is planned to be implanted. Although there is breast specimen for reference, the weight of breast specimen varied greatly when there are a lot of breast tissue or axillar content included. In such cases, precise preoperative volume estimation could lead to a better choice of prosthesis size, when you can only try once. However, in immediate reconstruction with autologous tissue such as DIEP flap, since we can discard piece by piece of the excess tissue until appropriate, then volume estimation is less helpful but still it can accelerate this process. Since there are many factors affecting the final result such as fatty tissue necrosis, swelling and discrepancy in volume with the opposite breast, we can use this tool for monitoring and design subsequent revision such as augmentation or reduction mammaplasty.