Objective To test and analyze out-of-field organ dose in intracranial tumor radiotherapy with or without wedges and in different radiation field areas. Methods The absorbed doses of out-of-field organs were measured using a thermoluminescent dosimeter by intracranial tumor radiotherapy simulation in the domestic phantom. The tests were grouped according to radiation field areas and techniques. Common square field techniques do not use wedges, whereas 3D conformal radiotherapy(3D-CRT) uses wedges. The radiation field area was divided into 2 cm × 2 cm and 4 cm × 4 cm fields. Results The absorbed doses of out-of-field organs ranged from 0.13 mGy to 2.83 mGy per 100 cGy prescription dose. The doses of organs adjacent to the target area are higher after irradiation using the 4 cm × 4 cm field than after irradiation using the 2 cm × 2 cm field(t=-5.023, P=0.004);however, no statistically significant(t=-1.438, P=0.171) difference can be found in organs non-adjacent to the target area. The doses of organs are higher after irradiation using 3D-CRT with a wedge than after irradiation using common square field techniques without a wedge regardless of whether the organs are adjacent to the target area or not (t 头=-2.805, P=0.038;t 腹=-11.966, P=0.000). Conclusions The absorbed doses of out-of-field organs of the patients who received intracranial tumor radiotherapy are associated with radiation field areas and techniques. The doses of organs adjacent to the target area increase as the radiation field area increases in size. Given a uniform radiation field area and prescription dose, the absorbed doses of out-of-field organs irradiated by radiotherapy techniques with wedges are higher than those of organs irradiated by radiotherapy techniques without wedges.

大量的实验研究和临床应用证明,外周血淋巴细胞染色体畸变分析是估算受照剂量较为可靠的生物学方法.常规染色体畸变剂量-效应曲线估算的剂量上限一般是5 Gy[1],解决大于5 Gy的剂量-效应关系,以扩大剂量-效应曲线的适用范围,对于受大剂量照射者的早期剂量诊断和临床救治非常重要.超大剂量照射以后,由于淋巴细胞数量急剧下降,用常规染色体培养方法在需要延长培养时间到70 h左右才能勉强收获到足够的中期分裂相以备分析[2].早熟染色体凝集技术可以克服常规染色体培养方法的不足,诱导间期染色体提前凝集,使可以用于分析的细胞数大大增加,从而易于染色体畸变分析.本研究拟在探索用花萼海绵诱癌素A(Calyculin A,CA)联合秋水仙素提前获取畸变染色体的可行性,并建立0 ～20 Gy X射线照射后的剂量-效应曲线,为超大剂量照射后剂量的快速准确估算提供一种新的方法。

目的探讨CalyculinA诱导早熟染色体凝集技术作为低剂量电离辐射生物剂量计的可行性。方法取健康成年人的抗凝外周静脉血,用X射线分别以0、0.1、0.25、0.5、0.75和1.0Gy照射。照射后将血样接种于RP-MI1640培养基中,于37℃、5%CO2恒温培养箱内培养48h,当培养24h时加入秋水仙素,终止培养前2h加入Calyculi-nA诱导早熟凝集染色体,收获制片并用Giemsa染液染色,观察G1、G2/M-PCC细胞中总畸变率、断片率、双着丝粒体加着丝粒环率与辐射剂量的效应关系。结果用CalyculinA可成功诱导人外周血淋巴细胞产生PCC,且总畸变率、断片率、双着丝粒体加着丝粒环率随照射剂量的增加而增加,最佳拟合曲线为二次多项式模式。结论 CalyculinA诱导PCC技术可以作为一种方法来估算低剂量受照者的辐射剂量,但是需要更多的资料来完善。

AIM: To investigate the differential expression of serum proteins in cirrhotic SD rats for exploring the pathogenesis and identifying the potential biomarkers of radiation-induced hepatic injury.METHODS: Liver cirrhosis was induced in 8 healthy SD rats with subcutaneous injection of carbon tetrachloride(CCl4) for 6 weeks and then the animals were randomly divided into 2 groups(4 rats in each group): control group(CCl4 alone) and experimental group(CCl4 plus radiation).The latter received hemi-liver radiation with single dose of 15 Gy while the former did not receive radiation.Total serum proteins of the 2 groups were extracted 6 h after radiation.Two-dimensional gel electrophoresis(2-DE) were performed to look for differentially expressed proteins.These proteins were then analyzed and identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF-MS).Western bloltting was used to validate the expression of heparanase and hepatocyte growth factor receptor in all independent series of serum samples.RESULTS: Two-dimensional gel images were acquired with good resolution and repetition.Thirty-three differentially expressed proteins were selected and 12 proteins were successfully identified by MS,in which 5 were up-regulated while 7 were down-regulated.The increased level of heparanase and decreased level of hepatocyte growth factor receptor were further confirmed by Western blotting.CONCLUSION: Twelve proteins associated with radiation-induced hepatic injury are successfully characterized by serum comparative proteomics.Heparanase and hepatocyte growth factor receptor might be useful for detecting and monitoring radiation-induced hepatic injury.