本研究主要目的在探討運用錐狀射束電腦斷層(cone-beam computed tomography, CBCT)應用於乳房保留手術 (breast-conservation surgery, BCS)患者的擺位不確定因子，對於三維空間向量(3D vector)之影響。影響乳房擺位因 子包括年齡、體重、身體質量指數(body mass index, BMI)、乳房體積數等。收集分析60位影像導引放射治療 (imaged-guided radiation therapy, IGRT)之乳房保留手術病患的擺位修正數據，進行三維位移空間向量計算，執行 複迴歸分析(multiple regression analysis)。由分析結果得知，影響乳房擺位因子之年齡、體重、身體質量指數、乳 房體積數等在統計學上缺乏相關性，也無統計上之顯著差異。然而病患年齡、體重、身體質量指數與乳房體積 大小無直接相關於影響病患擺位之準確性與精密度。故更應著重於病患模具製作上之品質專研與影像導引放射治 療之執行，以助益放射治療整體療效之品質。

This purpose of this study was to investigate the influence of uncertainty factors in the set-up of cone beam computed tomography in patients with breast conserving surgery on three-dimensional vector. Affect breast set-up factors include age, weight, body mass index, breast volume etc. Collecting and analyzing 60 patients with imaged-guided radiation therapy breast conserving surgery patient positioning correction data, three-dimensional displacement vector calculation, and the implementation of multiple regression analysis. According to the analysis results, there is no statistically significant correlation between the factors influencing breast set-up position factors such as age, weight, body mass index, breast volume, etc. There are also no statistically significant differences. However, the patient's age, weight, body mass index, and breast volume size are not directly related to the accuracy and precision of the patient's volume of treatment. Therefore, it should be more focused on the patient's mold making quality research and image-guided radiotherapy implementation. It will improve the overall efficacy of radiation therapy.