目的：利用放射線治療乳癌病患早已被證實可以有效減低局部復發率，但由於副作用太大，常使
得病患拒絕或中斷治療，效果因而大打折扣。造成這些併發症的主要原因是傳統斜對照方式的劑
量不均勻度過大所導致，這個實驗的目的則是找出一個最適切的治療方式來照射乳房部位，希望
未來可廣泛應用於臨床治療上。
材料與方法：在這次的研究評估數種乳房斜對照方式，分別以二種不同的方式來做比較和探討。
第一為治療計劃結果的比較，第二是利用假體及免沖洗底片驗證治療計畫系統計算準確度及各治
療方式執行的精準度等。以下四種治療技術將分別運用於6位乳癌病患的斷層掃描影像來執行治療
計劃：傳統斜對照、反算式強度調控放射治療（調強放療）斜對照、正算式調強放療斜對照、傳
統與調強放療結合（混合型調強放療）斜對照。
結果：與傳統斜對照比較，混合型調強放療、正算式調強放療與反算式調強放療三者均可達成較
佳的劑量分布。靶體積外組織大於110%給予劑量之區域，傳統斜對照是最大的；心臟劑量大於
30 Gy之體積比例，以反算式調強放療為最大；與患部同側肺部劑量，仍然以反算式調強放療最
大。比較假體實測與治療計畫的結果顯示，四種不同的照射方式都蠻符合的，但在假體邊緣皆出
現劑量高估的情形。
結論與討論：混合型調強放療不僅提升了靶體積的劑量均勻度，更重要的是在不增加肺部劑量的
前提下，大幅減少周圍軟組織的高劑量區，此外，值得一提的是，本技術之治療計劃及執行治療
所耗費的時間幾乎與傳統治療方式相當，不至於在機器或人力上造成額外的負擔。

Purpose : External-beam radiotherapy for breast cancer has been shown to reduce the local recurrence. The potentially important gains are often offset by side effect. A major contributing factor to these complications is the inhomogeneity of the dose distribution from tangential irradiation. The objective of this study is to find out the optimal method for breast irradiation which would be applied for clinical patient treatment in the future.
Materials and Methods : Several treatment techniques for tangential breast irradiation were evaluated in this study. The comparisons include two subjects. First, some clinical relevant factors were compared in the result of planning. Second, we will verify the delivery accuracy and delivery time for all techniques using phantom and GAFCHROMIC film. The following four plan techniques were applied for 6 patients: conventional tangents, Intensity modulated radiotherapy (IMRT) only tangents,forward IMRT tangents, and conventional open plus IMRT tangents (Hybrid IMRT).
Result : The IMRT only tangents, forward IMRT tangents and Hybrid IMRT achieved dose distributions better than conventional tangents. The volume of tissue outside the planning target volume receiving >110% of prescribed dose was largest for conventional tangents. Heart volume >30 Gy was largest for IMRT only tangents. Average total lung volume >20 Gy was largest for IMRT only tangents too. Compare the result in measurement and calculation. Overall, TPS showed good agreement with the measurement in all techniques. However, it was found that there were significant
discrepancies in the surface of the phantom.
Conclusion and Discussion : The hybrid IMRT improve the uniformity of target. The most important is reducing high dose area to the surrounding soft tissue while no increase dose to lung. Besides, planning and treatment time for hybrid techniques is almost the same with conventional technique.