Czerski P
J Microw Power Electromagn Energy. 1986;21(1):9-23.
The approaches and concepts used in the development of radiofrequency radiation (RFR) protection guidelines evolved over the past quarter of a century. The values of exposure limits (EL) proposed by various groups are converging. Early guides specified ELs in incident power density. Recent ELs are based on considerations of the relationship between bioeffects and the magnitude of the whole body average specific absorption rate (WBA-SAR) and current densities induced in the body. Both these quantities may be considered as dosimetric ones. Thresholds for untoward health effects expressed in terms of these quantities were suggested, and may be considered as basic ELs. It is possible to derive a frequency-dependent relationship between incident RFR fields and WBA-SAR and/or induced current densities in the body. ELs specified for the purpose of determining compliance in terms of electric and magnetic field strengths or equivalent plane-wave power density existing at a point where a person could be present, but measured in the absence of the exposed subject, may be considered as derived working limits. The rationales offered for the recommended ELs indicate that the principal consideration in establishing limits for frequencies of 10 MHz and higher is the prevention of thermal injury, thermal being defined as relatable to heating, i.e. an increase in temperature. At lower frequencies, below 100 kHz or 30 kHz, direct effects on membranes of nerve and muscle cells may be the limiting factor. An additional consideration is the hazard of shock and burns from contact with ungrounded large metal objects that are charged by RFR fields. Recent advances in RFR dosimetry led to concerns that exposure to presently accepted derived ELs may result in large local SARs and induced current densities in certain parts of the body. The present review concludes that further refinements to the basis for RFR should be introduced. Threshold for health hazards should be investigated taking into account both direct and thermal bioeffects of RFR. The dose-thermal effects relationships should be quantified using the concepts of SAR, SA and thermal dosage. Several unresolved questions, such as the biological basis for SAR time-averaging, and the limitation of pulse peak power, are briefly discussed.
在过去二十五年中，用于制定射频辐射（RFR）防护指南的方法和概念不断演变。不同组织提出的暴露限值（EL）数值正在趋同。早期指南规定的是入射功率密度的暴露限值。近期的暴露限值则基于对生物效应与全身平均比吸收率（WBA-SAR）以及人体中感应电流密度之间关系的考量。这两个量都可视为剂量学量。有人提出了以这些量表示的不良健康效应阈值，可将其视为基本暴露限值。可以推导出入射RFR场与人体中WBA-SAR和/或感应电流密度之间的频率相关关系。为确定是否符合规定而根据人体可能存在之处的电场和磁场强度或等效平面波功率密度指定的暴露限值（在无暴露对象的情况下测量），可视为导出工作限值。对推荐暴露限值给出的理由表明，在为10 MHz及以上频率设定限值时，主要考虑的是预防热损伤，热损伤定义为与加热相关，即温度升高。在较低频率下，低于100 kHz或30 kHz时，对神经和肌肉细胞膜的直接影响可能是限制因素。另一个需要考虑的因素是接触被RFR场充电的未接地大型金属物体而导致电击和烧伤的危险。RFR剂量学的最新进展引发了人们对接触目前公认的导出暴露限值可能会在身体某些部位导致较大局部比吸收率和感应电流密度这一问题的担忧。本综述得出结论，应对RFR的基础进行进一步完善。应在考虑RFR的直接和热生物效应的情况下，研究健康危害阈值。应使用比吸收率、比能和热剂量的概念对剂量-热效应关系进行量化。还简要讨论了几个未解决的问题，例如比吸收率时间平均的生物学基础以及脉冲峰值功率的限制。
