強度調控放射治療技術在嗅神經母細胞瘤之應用

背景及目的：嗅神經母細胞瘤(olfactory neuroblastoma)，由於其特殊解剖位置，不僅手術徹底根除不易，傳統放射治療亦不易達到良好的劑量分布。因此本科針對這樣的病患給予強度調控放射治療，以增加劑量均勻度、提高腫瘤劑量、降低正常組織的劑量及傷害。方法：針對病患術前MRI及術後CT定位影像，描繪出腫瘤及其周邊重要危急器官，繼而利用ADAC治療計畫系統分別以傳統二維和IMRT模式進行治療計畫。在IMRT計畫時輔以嘗試達到最佳腫瘤包覆及最低之腦組織、視神經、眼球劑量的最適化(optimization)過程。最後，在計畫完成時探討並比較各計畫之劑量分布狀況。結果：劑量上，傳統放射治療在腫瘤後緣及兩眼間，有包覆不良的現象；同時因係二維治療計畫，故有腦組織、視神經、眼球等正常組織之劑量體積分布無法評估的困難。相對地，IMRT技術在三維影像重組後，利用分段照野(segmental field)調控強度，恰可以克服傳統放射治療的困境。結論：最適化後所選定的照野方向及強度也可以成為未來同類型患者治療的參考，甚或成為一制式、可選用的治療模式。

關鍵字

知覺神經芽細胞瘤；嗅神經母細胞瘤；強度調控放射治療

並列摘要

Background and purpose: Because its particular location, olfactory neuroblastoma is a difficult malignancy to treat not only with radical surgery but also with conventional radiation therapy. In an effort to increase dose homogeneity, increase the dose to the tumor, and decrease damage to normal tissue, we incorporated IMRT into the treatment. Material and methods: After computed tomographic (CT) simulation, we delineated tumor and organs at risk by means of magnetic resonance imaging (MRI) and CT. Two-dimensional (2D) and IMRT treatment plans were obtained by using an ADAC treatment planning system. During IMRT planning, we used an optimization process to achieve better tumor coverage and acceptable doses for normal tissues. The dose distributions of each plan were evaluated and compared. Results: In terms of dosimetry, coverage of the tumor was inadequate, and evaluating the dose-volume relationship for organs at risk was difficult with conventional 2D plans. On the contrary, IMRT and the segmental field technique were good solutions. Conclusion: Such an IMRT plan with optimized beam directions, segments, and intensities may be one of the possible templates for use in patients similar to ours in the future.

並列關鍵字

Esthesioneuroblastoma ； olfactory neuroblastoma ； IMRT

國際替代計量

強度調控放射治療技術在嗅神經母細胞瘤之應用

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