在放射治療計劃的目標中，病人治療位置的穩定性與再現性是被嚴格要求的。然而，不管有無使用輔助模具，病灶與對位參考點間每次治療都存在著變異。就前列腺癌的病患而言，利用漲膀胱與排空直腸來配合治療計劃的方式，是臨床常規的做法之一。本研究，使用手動圈選感興趣區域(ROI)配合區域成長演算法，經由使用者界面(GUI)去分析和量化病人每日的膀胱大小。結果顯示：病人A的調控情形最佳，其四分位數的距離表示數值集中，其平均值為0.46，標準差為0.31，愈小的標準差代表每日的漲尿情形愈一致。本研究不只提供治療治劃所要求再現性數據，更避免病人其正常組織接受到過多的劑量。

In the goal of radiation treatment planning, reproducibility and stability of the treated position were strictly exacted. Whatever use of not assisted mold, the variation of patient lesion with tattoo mark is hardly to be identified. Using the filled bladder with empty rectum to coordinate treatment planning is very popular in clinical protocol for prostate patient. In this studies, application of manual tracing region of interest with region growing algorithm construct a graphical user interface to quantify the daily variation of bladder. The results revealed that controlled condition of patient A is the best, because of the distance of quartile is very concentrations, mean = 0.46, standard deviation = 0.31, however less and less of standard deviation represented constant filled bladder condition. In this studies, not only reveal the quantified data to assist treatment planning, but also deeply benefit treated patient to avoid received to much dose of normal tissue.