方法第1章要点分析.ppt

辐射危害 隐蔽不一察觉 损伤性非常大 与辐射的剂量以及部位有很大关系 对分裂的细胞的杀伤尤为严重 X射线防护 充分认识其危害 要有良好的安全意识 采用适当的方法 * 五、电离辐射警示符号 电离辐射标志 * 警告标志的含义是 使人们注意可能发生的危险。 电离辐射警告标志 * 国际原子能机构公布辐射警告新标志 ?国际原子能机构（IAEA）和国际标准化组织(ISO)2007年2月15日宣布启用一个新的放射性物质危险警告标志（ISO 21482: 2006）。 ?新标志将是对传统辐射警告标志的补充，但无意取代基本的电离辐射标志（ISO 361）。 ?新标志用以识别可导致死亡或严重损伤的危险源，即Ⅰ类、Ⅱ类和Ⅲ类放射源，例如辐照装置、远距放射治疗源、工业γ射线探伤源等。将该标志设置在贮源装置的表面，以警告人们不要试图拆卸装置或靠近该装置。这个标识在正常使用的情况下是不可见的，但是如果有人试图拆卸含有放射性物质的设备，它就会显露出来。 ?该标志不应设置在建筑物入口的门上，也不应设置在运输货包或集装箱表面。 * 参考资料 Biological Effects of Radiation are dependent upon: Total energy deposited Distribution of deposited energy Low dose, low-dose rate radiation exposure. The effects are in great dispute. It is thought that the effects of a protracted dose of radiation are not as great as with an acute dose because of biological repair mechanisms. Prenatal Radiation Exposure Sensitivity of the unborn Rapidly dividing cells are radiosensitive Potential effects Low birth weight - (most common) Mental retardation Chance of childhood cancer Bioeffects- X-rays and Skin Most radiation overexposures from analytical x-ray equipment are to the extremities. For x-rays of about 5-30 keV, irradiation of the fingers or hands does not result in significant damage to blood-forming tissue. At high exposures some general somatic effects to the skin can occur. Very high exposures may necessitate skin grafting or amputation of the affected extremity. Biological effects can be observed at 10 rem in special blood studies. Typically effects are visually observed at 50 to 100 rem. X-Ray Burns vs. Thermal Burns Most nerve endings are near the surface of the skin High energy x-rays penetrate the outer layer of the skin that contains most of the nerve endings so one does not feel an X-Ray burn until the damage has been done X-rays penetrate to the deeper, basal skin layer, damaging or killing the rapidly dividing germinal cells, that are destined to replace the outer layers * 2、修复。当吸收的辐射剂量达到一定水平时，细胞核内的DNA即可由于辐射的直接作用或者间接作用而受到损