Measurement of dose rate at the interface of cell culture medium and glass dishes by means of ESR dosimetry using thin films of alanine.
Measurement of dose rate at the interface of cell culture medium and glass dishes by means of ESR dosimetry using thin films of alanine.
复制标题
使用丙氨酸薄膜通过 ESR 剂量测定法测量细胞培养基和玻璃皿界面处的剂量率。
DOI：
10.2307/3580052
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发表时间：
1999
影响因子：
3.4
通讯作者：
Erik O. Pettersen
中科院分区：
文献类型：
--
作者：
Torbjørn Furre;E. S. Bergstrand;Eivind Pedersen;Marianne Koritzinsky;Dag Rune Olsen;E. Hole;Erik O. Pettersen
以前对人类宫颈癌细胞(Nhik 3025)的研究表明，当悬浮液中进行X射线照射时，这些细胞似乎比连接在玻璃培养皿上的细胞受到照射时更敏感。然而，这一结果取决于剂量测定，这在电池由于玻璃-液体界面的后向散射电子而附着在玻璃碟子上的情况下是困难的。最近发展起来的基于检测丙氨酸中辐射诱导的稳定自由基并使用ESR光谱的剂量学为玻璃-液体界面提供了比以前基于Fricke剂量学的剂量估计更相关的剂量测量的可能性。用薄的丙氨酸薄膜(~gt；/=10微米)照射薄膜，紧密贴在培养皿底部，覆盖1 mm蜡，模拟细胞上方的介质，测量界面上的剂量。还进行了Fricke剂量测定，在不同深度的Fricke溶液中，阐明了玻璃-液体界面上背向散射电子对剂量的贡献。在玻璃培养皿中用薄层Fricke溶液(0.2~0.3 mm)测量了1.9Gymin的剂量率。然而，这一估计似乎太高了，因为X射线穿过碟子上方4.5厘米的钢盖时产生的短程电子对剂量的贡献。使用丙氨酸薄膜进行剂量测量，玻璃-液体和塑料-液体界面的剂量率分别为1.15和0.87GY/min。因此，玻璃碟子上的后向散射电子对剂量有很大的贡献。我们之前观察到悬浮液中照射的细胞和附着在玻璃上的照射细胞之间存在辐射敏感性差异的原因似乎是在玻璃-液体界面缺乏准确的剂量学。
Previous studies on human cervical cancer cells (NHIK 3025) have indicated that the cells, when X-irradiated in suspension, appeared to be more radiosensitive than when they were irradiated attached to glass dishes. However, this result depends on dosimetry, which is difficult in the situation where cells are attached to glass dishes due to backscattering electrons at the glass-liquid interface. Recently developed dosimetry that is based on detection of radiation-induced stable radicals in alanine and uses ESR spectroscopy offers a possibility for more relevant dosimetry at the glass-liquid interface than the previous estimates of doses based on Fricke dosimetry. Thin alanine films (>/=10 microm) were used to measure dose at the interface by irradiating the films while they were placed tightly against the bottom of dishes and covered with 1 mm of wax simulating the medium above cells. Fricke dosimetry was also performed, with different depths of Fricke solution in the dishes, to elucidate the contribution to the dose delivered by backscattering electrons at the glass-liquid interface. A dose rate of 1.9 Gy/min was measured with a thin layer (0.2-0.3 mm) of Fricke solution in petri dishes made of glass. However, this estimate appears to be too high, due to a contribution to dose by short-ranged electrons generated when the X rays passed through a steel lid 4.5 cm above the dishes. Dosimetry using alanine films resulted in dose rates of 1.15 and 0.87 Gy/min at the interfaces of glass-liquid and plastic- liquid, respectively. Hence there is a significant contribution to dose from backscattering electrons on dishes made of glass. The reason for our previous observation of a difference in radiosensitivity between cells irradiated in suspension and cells irradiated attached to glass appears to be a lack of accurate dosimetry at the glass-liquid interface.