Haes D L, Fitzgerald M R
Massachusetts Institute of Technology, Radiation Protection Office, Cambridge 02139.
Health Phys. 1995 Apr;68(4):572-8. doi: 10.1097/00004032-199504000-00016.
It has been well established that video display terminals (VDTs) which employ the use of a cathode ray tube produce electric and magnetic fields of varying frequencies. Numerous studies have attempted to relate magnetic field exposure from VDTs in the extremely low frequency (ELF) and very low frequency (VLF) bands to adverse pregnancy outcome. Initial studies utilized VDT use time as a surrogate assessment of exposure, while later studies have obtained actual measurements. These measurements have been typically obtained at fixed distances from the screen. While VDT measurement criteria have been established for measuring VDT fields, criteria for the assessment of VDT user exposure has not. VLF magnetic and electric field measurements from approximately 140 and 40 different VDTs, respectively, were obtained over a 3-y period at the following positions: 0.50 m from the vertical centerline of the screen and at the approximate location of VDT user reproductive organs--0.30 m above the seat of the VDT operator in the working position. The measurement results of the two aforementioned locations were compared and demonstrate very little correlation. This lack of correlation indicates that VDT operator exposure assessment criteria are needed to determine any dose-response relationship between VDT electric and/or magnetic fields and adverse health implications.
业已明确，使用阴极射线管的视频显示终端（VDT）会产生不同频率的电场和磁场。众多研究试图将VDT在极低频（ELF）和甚低频（VLF）波段的磁场暴露与不良妊娠结局联系起来。早期研究将VDT使用时间作为暴露的替代评估指标，而后来的研究则进行了实际测量。这些测量通常是在距屏幕固定距离处进行的。虽然已经制定了测量VDT场的标准，但尚未制定评估VDT用户暴露情况的标准。在3年时间里，分别从大约140台和40台不同的VDT上获取了甚低频磁场和电场测量值，测量位置如下：距屏幕垂直中心线0.50米处以及VDT用户生殖器官的大致位置——在工作位置上VDT操作员座椅上方0.30米处。对上述两个位置的测量结果进行了比较，结果显示相关性很小。这种缺乏相关性表明，需要制定VDT操作员暴露评估标准，以确定VDT电场和/或磁场与不良健康影响之间的任何剂量反应关系。
