強度調控放射治療與傳統放射治療子宮頸癌治療計畫評估比較

放射線治療過程當中，誤差的來源主要來自於擺位上的誤差及器官的移動；而器官移動又包含整體組織的移動與腫瘤本身的移動，或是因為腫瘤本身的縮小而改變了組織位置。一般在骨盆腔放射治療中較少使用強度調控放射線治療(Intensity Modulation Radiation Therapy, IMRT)技術，理由是像子宮頸癌(Cervical cancer)會因為腫瘤體積變化而形成整個組織的移動。傳統的電腦斷層模擬定位(Computed Tomography simulation, CT-sim)都是在治療前做單一次的模擬定位，但是治療過程中可能就沒有再對腫瘤或組織的體積或構造做進一步的確認，因而容易造成劑量分佈的誤差。所以若是能在治療過程中試著做多次的模擬定位及根據模擬定位影像再製作治療計畫，便可以評估治療位置的準確性與評估IMRT技術是否使子宮頸癌的治療獲得準確的劑量。本研究同時利用不同的劑量評估方式：順形指標(Conformal Index)、均勻指標(Homogeneity Index)、劑量體積分佈圖(Dose Volume Histogram, DVH)、正常組織併發症機率(Normal Tissue Complication Probability, NTCP)以評估不同CT影像套用相同治療計畫的腫瘤覆蓋情形及IMRT與三度空間順形放射治療 (Three Dimensional Conformal Radiation Therapy, 3DCRT)在不同電腦斷層影像套用之間的差異。

關鍵字

強度調控放射治療；順形指標；均勻指標；劑量體積分佈圖；正常組織併發症機率

並列摘要

Setup error and organ motion are the major errors in radiation therapy delivery. Organ motions include the motions of the whole organ and the motions or shrinkage of the tumor. The Intensity Modulation Radiation Therapy (IMRT) technique is not used very often for the pelvic tumor treatment, such as cervical cancer, because the change of tumor volume will cause the entire organ motion. Commonly, computed tomography simulation (CT-sim) is used only once for treatment planning and never used again for re-plan during treatment. Therefore, it is easy to make dose coverage inaccuracy during treatment because of tumor shrinkage. We can evaluate the tumor location and dose delivered accuracy, as compared to the treatment planning, if we have extra CT simulations during treatment and design new plans based on these CT images. In our study, we applied different treatment planning evaluation tools, such as conformity index, homogeneity index, normal tissue complication probability, dose-volume histogram to evaluate the tumor coverage with the same treatment plans for different CT sets. We also compared the differences between 3DCRT (Three Dimensional Conformal Radiation Therapy) and IMRT(Intensity Modulation Radiation Therapy) techniques for the dose coverage.

並列關鍵字

Homogeneity Index ； Conformal Index ； Intensity Modulated Radiation Therapy ； Normal Tissue Complication Probability ； Dose Volume Histogram

參考文獻

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國際替代計量

強度調控放射治療與傳統放射治療子宮頸癌治療計畫評估比較

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