This paper mainly discusses the development status of solar radiation measurement technology,it expounds the relevant content of the current world radiation measurement datum and its standardization. Article the direc...This paper mainly discusses the development status of solar radiation measurement technology,it expounds the relevant content of the current world radiation measurement datum and its standardization. Article the direct radiation from the sun,the main measuring principle of total radiation and scattering radiation,this paper discusses the different types of radiation survey measuring elements,measuring range,emphasis and the current widespread use of measurement instruments. The development trend of future solar radiation measurement is put forward,and it is emphasized that nanotechnology and spectrum technology will become the focus of solar radiation instrument research and development.展开更多
目的 :探讨CT扫描中散射线剂量与管电流、管电压的关系,以及散射线降到机房本底水平所需的时间。方法 :首先记录扫描机房本底剂量水平,然后在CT检查床上放置体部水膜,按照A组140 k V、250 m A,B组120 k V、250 m A,C组140 k V、100 m A,...目的 :探讨CT扫描中散射线剂量与管电流、管电压的关系,以及散射线降到机房本底水平所需的时间。方法 :首先记录扫描机房本底剂量水平,然后在CT检查床上放置体部水膜,按照A组140 k V、250 m A,B组120 k V、250 m A,C组140 k V、100 m A,D组120 k V、100 m A 4组条件进行扫描,曝光时间均为5.1 s。于距离扫描架2.5 m处利用辐射剂量仪连续记录不同时间散射线剂量,同时采用高频摄像机记录剂量仪的数字变化,每种扫描条件重复扫描10次,记录曝光开始后30 s散射线辐射剂量,以辐射剂量仪显示的第7秒的数字作为曝光结束后的散射线剂量。结果:曝光结束后5 s内散射线剂量最大,随时间延长逐渐减低。扫描时管电流、管电压值越大,散射线剂量越大,曝光结束后最初5 s散射线剂量各组比较差异有统计学意义。不同扫描条件曝光结束后散射线剂量达到机房本底水平的时间为曝光后20~23 s。结论:散射线剂量与扫描时管电流、管电压有关。采用低剂量CT扫描可降低散射线强度。曝光结束后5 s内机房散射线剂量最大,CT操作技师应做好散射线防护。展开更多
文摘This paper mainly discusses the development status of solar radiation measurement technology,it expounds the relevant content of the current world radiation measurement datum and its standardization. Article the direct radiation from the sun,the main measuring principle of total radiation and scattering radiation,this paper discusses the different types of radiation survey measuring elements,measuring range,emphasis and the current widespread use of measurement instruments. The development trend of future solar radiation measurement is put forward,and it is emphasized that nanotechnology and spectrum technology will become the focus of solar radiation instrument research and development.
文摘目的 :探讨CT扫描中散射线剂量与管电流、管电压的关系,以及散射线降到机房本底水平所需的时间。方法 :首先记录扫描机房本底剂量水平,然后在CT检查床上放置体部水膜,按照A组140 k V、250 m A,B组120 k V、250 m A,C组140 k V、100 m A,D组120 k V、100 m A 4组条件进行扫描,曝光时间均为5.1 s。于距离扫描架2.5 m处利用辐射剂量仪连续记录不同时间散射线剂量,同时采用高频摄像机记录剂量仪的数字变化,每种扫描条件重复扫描10次,记录曝光开始后30 s散射线辐射剂量,以辐射剂量仪显示的第7秒的数字作为曝光结束后的散射线剂量。结果:曝光结束后5 s内散射线剂量最大,随时间延长逐渐减低。扫描时管电流、管电压值越大,散射线剂量越大,曝光结束后最初5 s散射线剂量各组比较差异有统计学意义。不同扫描条件曝光结束后散射线剂量达到机房本底水平的时间为曝光后20~23 s。结论:散射线剂量与扫描时管电流、管电压有关。采用低剂量CT扫描可降低散射线强度。曝光结束后5 s内机房散射线剂量最大,CT操作技师应做好散射线防护。
