熱發光劑量計用於度量鈷六十遠隔治療機伽馬射線在假體中劑量的分析

THE APPLICATIONS OF THERMOLUMINESCENT DOSIMETERS IN MEASURING THE DOSE DISTRIBUTION IN PHANTOM FROM TELETHERAPEUTIC COBALT-60 GAMMA-RAYS

朱國龍(Guo-Long Chu) ； 黃淑珍(Shu-Chen Huang) ； 許彬杰(Pin-Chieh Hsu) ； 翁寶山(Pao-Shan Weng)

《中華放射線醫學雜誌》 2卷4期 (1977/12) Pp. 341-350

摘要

本文係以熱發光劑量計配合放射治療專用的假體，以度量國人易罹致鼻咽，子宮，肺癌等病灶的鈷六十伽馬輻射劑量分布。實驗前的校正工作，至為重要，尤其是劑量計在假體中的自屏蔽效應，本文均加以討論。從度量的數據，可求出肺和骨對伽馬射線衰減的情形，再與文獻所提供的實驗結果互相比較印證，以確定本實驗的可靠性。由實驗獲得的度量數據，與遠隔治療機製造廠所提供的等劑量曲線比較，並輔以照相偵檢方法作為佐證。結果顯示用熱發光劑量計度量病灶的等劑量曲線，較照相偵檢方法為優;再回合放射治療專用的假體，較製造廠所提供的數據更接近於實際情況。本實驗除提供鼻咽，子宮，肺等病灶的等劑量曲線外，復附加其縱剖面的劑量分布圖。

並列摘要

This paper is dealing with the application of thermoluminescent dosimeters in measuring the exposure distribution in a Rando phantom from a teletherapeutic ^(60)Co gamma-ray with reference to nasopharyngeal, uterus cervical, and pulmonary tumors which are predominant in Chinese subjects. The self-shielding effect of dosimeters located inside the phantom should be carefully examined and determined before the experiments are carried out. This important factor is discussed in this paper. The attenuation of gamma-ray in lung and bone obtained from experimental results was compared with data given in the literature. The agreement of the comparison mentioned above indicated the reliability of the experimental results. All data measured were compared with those provided by the teletherapeutic machine manufacturer in the form of isodose curves. Photographic film detectors were also used as a secondary comparison. The results of comparison show that thermoluminescent dosimeters are superior to photographic film detectors, and the Rando phantom is superior to water phantom used by the manufacturer since Random phantom is much closed to the composition of human body. In addition to the isoexposure curves for nasopharyngeal, uterus cervical, and pulmonary tumors, the exposure distribution of the vertical section of phanton is also included.