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題名 | 高能放射治療射束對正常組織中子等效劑量污染評估研究=The Evaluation of Photoneutron Dose Equivalent for Normal Tissue with High Energy Beams |
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作者 | 熊佩韋; 林招膨; 盧勇發; 張幗孫; 林豐義; 劉幕台; Shueng, Pei-wei; Lin, Jao-perng; Lu, Yong-fa; Chong, Ngot-swan; Lin, Feng-yih; Liu, Mu-tai; |
期刊 | 中華放射線醫學雜誌 |
出版日期 | 20030400 |
卷期 | 28:2 2003.04[民92.04] |
頁次 | 頁83-89 |
分類號 | 414.93 |
語文 | chi |
關鍵詞 | 光中子; 中子等效劑量; 氣泡式偵檢器; Photoneutron; Photoneutron equivalent dose; Bubble detector; |
中文摘要 | 目前國內外的文獻研究多偏向於量測治療室內中子之空間分佈情形,對於實際病人或治療室外工作人員之劑量接受情形較少討論。本研究是應用Siemens PRIMUS 直線加速器評估患者在治療過程中所接受之光中子劑量污染,在其15MV光子能量射束的照射下,將BD-PND氣泡式偵檢器(偵測快中子)和BDT氣泡式偵檢器(偵測慢中子),分別將其置於水假體(Water Phantom)中進行量測。在不同射束照野(10X10cm2和40X40cm2)、不同深度(水假體表面及深度5、10、15、20、25、30cm)及距離射束中心軸不同距離時(離軸3、5、10、15及20cm),分別量測其光中子在水假體中分佈的情形。並將所得到的量測結果進行分析討論,以評估患者於放射治療中接受光中子污染的等效劑量。實驗的結果顯示不論是在射束照野10X10cm2或40X40cm2照射下,光中子所造成的快中子和慢中子等效劑量,都是隨著治療深度的增加而減少;且快中子所造成的污染量比慢中子多了5倍之多,由此可知,高能醫用直線加速器所造成的光中子污染中,快中子佔了主要部分。而在10X10cm2的射束照野下,在水假體表面和深度10cm時,其光中子造成的快中子和慢中子等效劑量,是隨著距射束中心軸的距離愈遠而減少;且在射束照野之外所造成的光中子污染量更是急劇衰減。應用氣泡式偵檢器的量測標準差平均約+-15%,顯示本實驗利用氣泡式偵檢器的量測結果是可接受的。 |
英文摘要 | The aim if this research was to measure the dose equivalent of photoneutron produced from 15MV x-ray. By the way, we can estimate the doses from photoneutron contaminations for patients treated under similar conditions. The dose equivalent of photoneutron were be measured by BD-PND and BDT bubble detectors that were produced by BTI. The BD-PND was used to measure the dose of fast neutron and the BDT was used to measure the dose of slow neutron. The detectors were installed both at central axis and off-axis in the water phantom. Measurements were done at various depths (at the surface of water phantom, and the depths of 5, 10, 15, 20, 25 and 30 cm) with different fields (10X10cm2 and 40X40cm2) and at different distance from central axis (off-axis 3, 5, 10, 15 and 20 cm). Then, the photoneutron contaminations could be evaluated. The average of standard deviation in this study is about within ±15%. The results of experiment show that both the dose equivalent contributed by fast neutron and slow neutron are decreasing with increasing of depth and off-axis distance. We also found that fast neutron is in the majority of photoneutron produced from LINAC. Beside, the contamination contributed by photoneutron is drop off swiftly outside the photon beam. |
本系統之摘要資訊系依該期刊論文摘要之資訊為主。