臺灣博碩士論文加值系統

醫療的進步，提升了人們的生活水準，新的醫療技術發展，使品質控管更為重要，立體放射手術即為一例，它是針對腦神經外科，在治療頭顱內患有病灶之病人所使用的一種不用開刀的技術。在輻射劑量學中，利用傳統的劑量計例如游離腔、二極體偵檢器、熱發光劑量計、感光膠片…等，來量測等劑量曲線或是深度劑量分佈都有其適用的範圍及其限制。輻射變色軟片則具有高度空間解析度、測量時不用特殊處理步驟，且能將測量後結果永久的保存下來等優點。
本研究將探討輻射變色軟片偵測輻射之特性，包括軟片反應與時間關係、劑量線性度、能量依存度及角度依存度；並使用加馬刀立體定位放射手術劑量驗證用之球型假體，量測加馬刀四種不同大小準直儀頭盔之劑量分佈及相對輸出因子，並與蒙地卡羅模擬結果作一比較分析。比較其兩者結果，平均差異介於1.5 ％～3 ％之間，落於合理的誤差範圍之間，有相當的準確性。對於立體定位放射手術的品質確認和治療劑量的輸出，輻射變色軟片提供了另一精確的量測工具。

The progress in medical science and technology brings great hope to a life of better quality. However, better and more efficient medical treatments have made quality assurance an even more important issue. For example, the stereotactic radiosurgery. The stereotactic radiosurgery is a technique dealing with patients who have brain tumors. By irradiating high and localized dose to lesion, the patient will have a better surviving rate and a higher functional life afterwards.
In radiation dosimetry there are numerous limitations associated with the measurement of isodose curves and depth-dose distributions in high gradient regions of beams by using conventional measuring systems, such as ionization chambers, diode dosimeter, thermoluminescent detectors, and radiographic films. These difficulties have resulted in a search for a radiation dosimeter with high spatial resolution which does not require a special developmental procedure and gives permanent absolute values of absorbed dose with an acceptable accuracy and precision and ease of handling and data analysis.
The purpose of this study is to analyze the characteristics of radiochromic film dosimetry, including the film response versus time, dose linearity, energy dependence and angular dependence. In addition, we measure the output factors for the field defining collimators used in gamma knife by using spherical phantom. The measurement results were compared with the results of Monte Carlo simulation. The outcome showed the average deviation between the results from experimental measurement and Monte Carlo simulation was about 1.5 ﹪~3 ﹪which was within the uncertainty range and proved to agree with each other. For actual dose measurement, the radiochromic film offers a good test tool for dosimetry and quality assurance.

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