【摘要】 目的:模拟调强放射治疗模式研究延长分次照射时间对人鼻咽癌细胞系CNE1放射生物效应的影响。方法:研究分组为急速照射组(A组):设0、1、2、4、6、8Gy共6个剂量点,剂量率为2Gy/min,每个剂量点照射单次完成;延长时间照射组(B组),剂量点和剂量率同A组,按照射时间和模式又分为B1组:分2次,15min完成;B2组:分8次,15min完成;B3组:分15次,20min完成;B4组:分22次,30min完成。克隆集落形成试验计算细胞存活率。单击多靶数学模型拟合细胞存活曲线,计算Do,Dq,SF2的值。银染核仁组成区技术观察增殖动力学参数AgNOR面积与胞核面积之比(I/S%值)。结果:B组与A组相比,细胞存活率提高5%-10%,有统计学意义。B3、B4组与B1、B2组相比,细胞存活率提高,有统计学意义。A组、B2组和B4组的Do值为0.56Gy、0.60Gy、0.70Gy;Dq值为1.18Gy、1.24Gy、1.30Gy;SF2值为0.209、0.261、0.324;放射前后不同时间点,不同组间的增殖动力学参数(I/S%值)较常规照射没有发生显著变化。结论:IMRT较常规照射对肿瘤的控制率降低,照射剂量200cGy,小于30min的照射时间内肿瘤细胞的增殖动力较常规照射没有发生明显变化。更多还原

【Abstract】 Objective:To investigate the impacts of radiobiological effect of protraction fraction time in IMRT on human nasopharyngeal carcinoma cell line CNE1. Methods: Human nasopharyngeal carcinoma cell line (CNE1) was irradiated with protocols of increasing dose delivery protraction by different models: (A)acute irradiation model: the cell were irradiated at 0,1,2,4,6,8Gy dose level by 6MV X ray, 2Gy/min.(B)IMRT model with the same dose level and rate with acute irradiation group:(B1)irradiation in 15 min by 2 fractions.(B2)irradiation in 15 min by 8 fractions.(B3)irradiation in 20 min by 15 fractions.(B4)irradiation in 30 min by 22 fractions. Clonogenic cell survival analysis was performed after irradiation experiments. The values of Dq,Do and SF2 were caculated according to the"single-hit multi-target group".AgNORs staining was used to determine the cell repopulation dynamics. Results: The cell survival rates showed significant increase in IMRT model compared to acute irradiation and had a significant increase in the group with delivery time more than 15 minutes.The values of Do in Group A,B2,B4 were 0.56Gy,0.60Gy and 0.70Gy,Dq were 1.18Gy,1.24Gy and 1.30Gy,SF2 were 0.209,0.261 and 0.324,respectively. There was no significant difference among both post-radiation groups and different periods after radiation compared to acute group. Conclusion: Even at fraction times of 15-30 minutes the protracted dose delivery increases the survival rates in cell culture. Besides, there is a tendency that the survival rate increases if the fraction dose delivery time becomes longer. The altered survival rates indicate the importance of the dose rate in the effect of IMRT. The cell repopulation dynamics showed no change in IMRT compared to conventional application in our research. More researches are needed to discuss the results.更多还原