目的:由於銥192有複雜的γ能譜,所以再計算一個標準包裝的microSelectron-HDR銥192射源之空氣克馬率常數Γδ。用已校正的TLD- 700氟化鋰(LiF)晶片來測量上述射源之空氣克馬。比較劑量的再計算值與測量值。結果亦可應用於新購銥192射源的活度修正。 材料與方法:重新查閱銥192的同位素表之數據後,再計算其空氣克馬率常數Γδ。用銫137射源校正的TLD-700 LiF晶片來測量上述射源之空氣克馬。 結果:對於一個標準包裝的microSelectron-HDR欽192射源而言,考慮0.25 mm厚的不鏽鋼對γ射線所造成的衰滅,空氣克馬率常數Γδ為2.944*10-17Gy m2s-1Bq-1。利用TLD700 LiF晶片來測量10居里(Ci) microSelectron-HDR銥192射源之空氣克馬,所得的結果與再計算的Γδ值相比較。 結論:對於一個新的銥192射源而言,Γδ的再計算值與microSelectron-HDR銥192射源的空氣克馬測量值之間的差異是很有用的。
Purpose: Due to the complex γ- ray spectrum branchings of 192Ir, the air - kerma rate constant Γδor a standard packaged microSelectron-HDR 192Ir source was recalculated. The calibrated TLD-700 LiF chips were used to measure the air-kerma of the above mentioned source. The results of dose recalculation and measurement were compared. The results could be applied in activity correction for a new 192Ir source. Materials and Methods: After reviewing table of isotope data for 192Ir, the air-kerma rate constant Γδwas recalculated. TLD-700 LiF chips calibrated with a standard 137Cs source were applied in the air-kerma measurement of the source mentioned above. Results: For a standard packaged microSelectron-HDR 192Ir source, taking into account attenuation of γrays in 0.25 mm stainless steel, the air-kerma rate constant Γδ was obtained as 2.944*10-17Gy m2s-1Bq-1. Results of air-kerma measurement using TLD-700 LiF chips for a 10 Ci microSelectron-HDR192Ir source was compared with theΓδ recalculation. Conclusion: The difference betweenΓδ recalculation and air-kerma measurement for microSelectron-HDR192Ir is useful in the activity calibration of a new 192Ir source.