電腦化放射治療計畫系統的應用

APPLICATION OF COMPUTERIZED TREAMTNET PLANNING SYSTEM IN RADIOTHERAPY

許梧悌(W. T. Hsu) ； 陳光耀(Kuang Y. Chen)

《中華放射線醫學雜誌》 5卷2期 (1980/06) Pp. 198-210

摘要

癌病放射治療的劑量核算，傳統上都用手使用簡單的計算器運算，針對腫瘤的部位和深度以遠距或近接治療實況，參考有關的劑量分布表或等劑量曲線圖，這樣的核算，往往只能作重點式的計算，個別病人複雜治療的體內等劑量圖幾不可得。自從發明了電腦化治療計畫系統以後，有關的劑量分布表或等劑量曲線圖，可以預存在電腦記憶系統中，病人的體表輪廓，體內腫瘤及重要器官等資料，可由圖數轉換機輸入，治療的條件諸如照野的大小、角度、楔形濾板的加用和選擇，多照野治療次數比率等經適當選擇後，體內等劑量曲線圖交由電腦運算後在顯示機呈現，如屬滿意並需要永久記錄，除了儲存在磁帶裏預備日後重複顯示及應用外，亦可經由印字繪圖機輸出，存放於病歷中。榮民總醫院癌病治療中心於1979年9月購入Varian RO7治療計畫系統，該系統優點之一是有一項選優功能，於接受醫師對腫瘤和限制點劑量處方指示後，會自一兩百個可能排列組合的治療條件中，呈現少數最優良的安排。電腦化治療計畫系統若用電腦斷層攝影像資料，對腫瘤部位和劑量分布的掌握更爲確實，腫瘤控制率應能提高。同時因能避免重要器官的照射和傷害，治療產生併發病的機會也會減少。本文的目的卽在介紹Varian RO7治療計畫系統的特性，並用圖說明該系統的外形，工作原理和一些病人實例。

並列摘要

Using depth dose chart and isodose curves relevant to location and depth of the tumor, traditional hand calculation of radiation dosage in cancer teleradiotherapy and brachytherapy usually provide information only for certain key points. Calculation of isodose curve around the tumor is tedious even for simple treatment arrangements. When a computerized treatment planning system for radiotherapy is available, radiation beam data from treatment machines may be stored in the system. This will then interact with individual patient information, such as body contour, tumor outline and internal organs which can be input by digitizer. The final isodose curves will be shown in the T.V. monitor. Size, angulation .and weighting of portals, as well as application and selection of wedge filters can then be manipulated. The optimal treatment planning may be stored in the system or printed out. Cancer Therapy Center of Veterans General Hospital has used a computerized treatment planning system (Varian RO7) since September 1979. One characteristic of this system is the function of optimization, which presents a best-treatment planning according to the tumor dose and the limitation of the constraint points prescribed by the radiation oncologist. This paper introduces the Varian RO7 treatment planning system, its working principles, and some actual cases. When patient information is obtained from a computed tomogram and the output is shown by the hardcopy of printer/plotter, this system is such a powerful and accurate tool in radiotherapy that the tumor control rate should be improved and the complication rate should be decreased.