Reply to Kromhout et al.
WE THANK Kromhout et al. for their letter and the opportunity to explain that, because it is explicitly an ICNIRP Statement as distinct from ICNIRP Guidelines, ICNIRP did not undertake a full systematic review for the document Statement on Diagnostic Devices Using Non-ionizing Radiation: Existing Regulations and Potential Health Risks (ICNIRP 2017). Non-systematic literature reviews are used to identify major issues relating to a topic, starting with high levels of evidence and appraising lower levels as necessary. We agree that they carry the potential for bias, and therefore they should not be the basis of formulating recommendations, which is the purpose of Guidelines.
The ultimate aim of the Statement was to identify situations of potentially high NIR exposure to patients or health care workers from diagnostic devices employing NIR that are currently in clinical use, where protection from possible health effects by regulations and policies may not be adequate and might warrant a further in-depth and systematic analysis. ICNIRP agrees that some studies have reported transient health effects of MRI such as highlighted by Kromhout et al. in their letter and indeed refers to several such studies in the Statement. In its 2014 Guidelines for limiting exposure to electric fields induced by movement of the human body in a static magnetic field, ICNIRP states that vertigo and nausea may be annoying and disturbing, but they are not considered to indicate serious long-term health effects (ICNIRP 2014). No chronic health effects or safety risks resulting from the use of MRI have been substantiated that could be associated with inadequacies in existing regulations.