Radiation literature survey

Article publication date

14 April 2025

ARPANSA review date

19 May 2025

Summary

This computational modelling study evaluated the relationship between current computed tomography (CT) scanning practices and future incidence of cancer in the USA. Data on CT use was extracted from a market outlook survey of hospitals and imaging facilities in the USA. CT scans were subdivided into categories and an average dose per category was determined using data from a US CT dose registry. Subsequently, absorbed doses were estimated for different organs through radiation transport simulations. Using information from the US National Research Council Biological Effects of Ionizing Radiation (BEIR) VII report, lifetime cancer risks corresponding to the calculated absorbed organ doses were computed. A sample of 121212 examinations was used to determine the proportion of scans for each CT scan category. By combining the lifetime cancer risk per CT scan type with the data on total CT scans, the total risk to the USA’s population was estimated.

The article computed that approximately 93 million CT scans were undertaken in the USA in 2023, with persons in the 60-69 age bracket undergoing the most examinations. Examinations performed in the last year of life were excluded for cancer estimates leaving 84 million CT scans which were modelled to result in 102700 cancers over the projected lifetime of the exposed patients. This is currently equivalent to approximately 5% of new cancers in the USA each year.

Published in

Journal of the American Medical Association Internal Medicine

Link to study

Projected Lifetime Cancer Risks From Current Computed Tomography Imaging | Radiology | JAMA Internal Medicine | JAMA Network

Commentary by ARPANSA

The use of ionising radiation, such as CT scans, in medicine involves a balance between benefit and risk. The article makes good use of some large databases, and models derived from epidemiological data, to assess long-term cancer risks from CT utilisation in the USA but does not attempt to address the benefit side of the equation. CT scans provide significant benefits to patients by enabling accurate and timely diagnosis, often avoiding the need for more invasive procedures, or identifying disease at an early stage when it can be effectively treated. Medical staff requesting CT scans must justify them by considering the balance of benefit and risk for each patient. Imaging staff must optimise scan settings to balance radiation exposure with the image quality needed for the diagnostic task. The risks identified in the paper underline the importance of continued and effective implementation of these principles of justification and optimisation.

The study uses cancer estimates from the BEIR VII risk model and as such inherits its limitations. The primary limitation is that the model is based on cancers observed in cohorts of survivors from the atomic weapons detonations in Hiroshima and Nagasaki and uncertainties remain in applying this information to other situations. The BEIR model estimates for the relationship between cancer risk and ionising radiation exposure are not new and have not changed for decades. In this sense the current paper does not present new information on the relationship between exposure and cancer risk but rather is using cancer risk as a tool to highlight potential issues with scan over-use. Additionally, the study's risk calculations factored in average life expectancies, which may overestimate future cancer risk for patients with shorter life expectancies due to underlying illness.

While our understanding of the relationship between exposure and cancer risks remains the same, advancements in CT scanning technology have significantly lowered patient doses and improved scan quality. ARPANSA’s National Diagnostic Reference Level (DRL) Service has tracked these optimisations, with data demonstrating that doses for common procedure types have been steadily decreasing over the last decade.

The study estimated 273 CT scans per 1000 population in the USA. In comparison, the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) 2021 global survey reported 238 scans per 1000 population for the USA and 157 scans per 1000 population in Australia, both of which are comparable to the average for countries at the highest income level (159 scans per 1000 population). The lower prevalence of scans, in conjunction with the dose reductions mentioned above, indicate that similar modelling for Australia would give a substantially lower estimate on the projected number of cancers from CT scans. 

Most importantly, results from the study should be considered in the clinical context of CT scans. CT scans are performed for diagnostic purposes on unwell patients and the diagnostic benefits of the scan must be weighed against the potential harms. This principle of justification, along with the optimisation mentioned above, must be applied to all medical ionising radiation exposures in Australia as outlined in the Code for Radiation Protection in Medical Exposure RPS C-5. Simply, the conclusion presented by the paper does not account for the diseases treated and prevented by undergoing a scan and should not be cause for hesitancy in patients who have been prescribed a scan by their medical professional.  However, it does underline the importance of continued monitoring and vigilance in the usage of ionising radiation in medical procedures, including the use of referral guidelines and comparison of doses to diagnostic reference levels. These principles, advocated by the International Commission on Radiological Protection and highlighted in the Bonn Call for Action, a joint position statement by the International Atomic Energy Agency and the World Health Organization, continue to guide international best practice for the use of ionising radiation in medicine.

Article publication date

December 2024

ARPANSA review date

May 2025

Summary

This cohort study examined rates of cancers among people who lived in apartments and were exposed to extremely low frequency electromagnetic fields (ELF EMFs) from  electricity transformers. The exposed population was categorized into three groups: most exposed (individuals living in ground and first-floor apartments adjacent to the transformer room, n = 8,840), unexposed (individuals living on higher floors, n = 179,285), and partially exposed (individuals living on the ground and first floors but not adjacent to the transformer room, n = 52,599 Cancer diagnosis was based on entry in the Finnish Cancer Registry. The study compared the number of cancers that occurred in the apartment buildings to the average numbers that occur based on the Finish Cancer Registry. The study found no association between ELF EMF exposure and cancer incidence when all cancers were examined together (all site cancers standardized incidence ratio (SIR) 1.01, 95% confidence interval (CI) 0.93-1.09). However, when cancers were examined individually, a statistically significant association was observed for the exposed group with digestive organs cancers (SIR 1.23 95% CI 1.03-1.46) [overall], and more specifically with gallbladder cancer (SIR 3.92, 95% CI 1.44-8.69), and small intestine cancer (SIR 2.67, 95% CI 1.08-5.56). Overall, the study reported no elevated risk of cancers associated with the ELF EMF exposure due to living near an electrical transformer; however, it showed an elevated risk of digestive organ cancers due to the ELF EMF exposure. 

Published in

Occup Environ Med

Link to study

Magnetic fields from indoor transformer stations and risk of cancer in adults: a cohort study - PubMed

Commentary by ARPANSA

The study found that the overall risk of cancer was not associated with living near an electrical transformer. However, it found an association with digestive organ cancers, including small intestine and gallbladder cancer. There were a few notable limitations for this study that challenges the observed associations for risk. For example,  the study did not take into account any confounding factors such as socioeconomic status or the main risk factors for digestive organ cancers such as eating habits (Zhang et al, 2021). These limitations make the interpretation of the study findings difficult as these unaccounted known risk factors could be the cause of the statistically significant association with digestive organ cancers.

ELF EMF exposure was based on distance to a transformer not measurements and this could result in exposure misclassification. As shown in the paper by Okokon et al, (2014) there is a large spread in the exposure observed in apartments adjacent to transformers. This means that the apartments may not be areas with a higher magnetic field and the cancers observed in the study have nothing to do with exposure to ELF EMF.

Some epidemiological studies observing outcomes from exposure to ELF EMF greater than 0.3 or 0.4 µT have shown an association with childhood leukaemia (SCENIHR 2015). However, this association has not been established by consistent scientific evidence. The epidemiological evidence for this association is weakened by various methodological problems such as potential selection bias, misclassification and confounding. Furthermore, it is not supported by laboratory or animal studies and no credible theoretical mechanism has been proposed on how ELF EMF exposure could cause cancer (Karipidis et al, 2024). Overall, the scientific evidence does not establish that exposure to magnetic fields in the everyday environment is a hazard to human health. 

It is ARPANSA’s assessment that based on current research, there is no substantiated scientific evidence that exposure to ELF electric fields below the international guidelines is a health hazard. More information about exposure to ELF EMF can be found on the ARPANSA factsheet Electricity and health | ARPANSA.

Article publication date

May 2025

ARPANSA review date

May 2025

Summary 

This systematic review evaluated the literature for evidence of a relationship between radiofrequency electromagnetic field (RF-EMF) exposure and cancer incidence as reported in animal (in vivo) studies. After searching the literature for appropriate articles, 52 studies were found suitable for inclusion in the review. Each article was assessed for risk of bias (RoB) according to the method described by OHAT. Cancer endpoints where a statistically significant result was reported in the literature were progressed to full analysis and a certainty of evidence (CoE) evaluation was conducted according to GRADE. The review reported that the included studies were too heterogeneous to combine in a meta-analysis and the authors elected to base their findings on statistically significant results which occurred in a very small subset of the included studies.

No evidence was found for any cancer outcome in most biological systems including gastrointestinal, kidney, mammary gland, urinary, endocrine, musculoskeletal, reproductive and auditory. The review reported moderate certainty evidence for an increased incidence of lymphoma, liver cancer, and lung and adrenal gland tumours in response to RF-EMF exposure. The review also reported high certainty evidence for an increased incidence of brain cancer (glioma) and heart cancer (malignant schwannoma) in response to RF-EMF exposure. 

Published in

Environment International

Link to the study

Effects of radiofrequency electromagnetic field exposure on cancer in laboratory animal studies, a systematic review

Commentary by ARPANSA

The systematic review conducted a high-quality search and identified all the appropriate studies, collating a large evidence base. However, their results placed particular emphasis on just two studies: the National Toxicology Program (NTP) 2018 study and the study by Falcioni et al (2018). Many of the methodological failures of those studies, outlined in reviews by health organizations including ARPANSA, ICNIRP, and the US FDA, were not adequately considered in this review. Specifically, issues such as the lack of blinding in pathological assessments, unexplained differences in cancer incidence between male and female animals, and the longer lifespans of exposed animals resulting in a higher chance for tumours to develop were overlooked. Additionally, the studies failed to account for chance in their statistical analyses, leading to potential false positive results. For example, with 12,800 tests made in the NTP (2018) study, many hundreds would be expected to be significant due to chance alone. These methodological weaknesses, combined with inconsistencies in the findings between the two studies and with other literature, make it difficult to reconcile the weight the authors placed on the conclusions regarding RF-EMFs and cancer risk from these studies.

One of the most important parts of a systematic review is the synthesis of results. This is when all the results from previous studies are combined, allowing the evidence to be assessed as a whole rather than as individual pieces. Unfortunately, the authors of this systematic review elected not to consider the evidence in its totality and instead focused on a small number of positive findings. The review considered RF-EMF to have an effect on cancer if at least one study showed a significant effect (on exposed versus not-exposed) or significant trend (across different exposure levels) regardless of other studies not finding an effect or trend. Further, a trend could be calculated as statistically significant even if it was based on individual non-significant results across different exposure levels. This issue is demonstrated repeatedly in the review, most prominently in the assessment of brain tumours, lymphoma, and heart schwannomas. It is particularly egregious for glioma, with the authors purporting a high certainty of an increased risk of brain tumours. This is despite there being no single significant result across all studies, with the reviews reported outcome based on insignificant results from a single paper (NTP, 2018) that have been interpreted as a significant trend. Furthermore, the very low actual numbers of glioma tumours reported in the NTP (2018) study make this trend very tenuous, as a single tumour in the control group would have resulted in a non-significant trend. The review focused on this trend in their results and ignored the many non-significant outcomes reported by other studies. The approach taken by the authors to consider only positive outcomes fails to consider all of the available evidence, ultimately defeating the purpose of conducting a review.

Another point to consider with the synthesis is the absence of a meta-analysis. The authors reported that the studies were too heterogeneous for a meta-analysis to be performed. Although this rationale could be considered valid, in another recent systematic review on cancer in laboratory animals conducted by Pinto et al. (2023), a meta-analysis was performed. The Pinto et al systematic review found that there was low or inadequate evidence for an association between RF-EMF exposure and the onset of tumours of any type. 

The risk of bias (RoB) assessment in the current systematic review aimed to evaluate the methodological rigor and transparency of included studies by considering six key bias domains:  selection bias,  performance bias,  detection bias,  attrition bias,  selective reporting and other sources of bias. There are several issues with the conduct of the RoB in this review which results in inappropriately generous characterisations of the included studies. Many of the limitations of the included studies, particularly those reporting positive findings for glioma and malignant heart schwannomas in male rats (Falcioni et al., 2018; NTP, 2018a; b), were not adequately considered. The authors did not acknowledge the well-documented flaws with these two studies that have been extensively commented on by ARPANSA and ICNIRP and have consequently under-represented the RoB in the conclusions of these studies. These choices in the RoB assessment are crucial as these two studies overwhelmingly informed the conclusions of the present review.

The systematic review’s evaluation of statistical methods used by the included studies was also inadequate. This is again particularly problematic for the key studies used to support their conclusions. In the NTP (2018) study, sharing of control groups amplified the likelihood of outcomes being found by chance and the lack of corrections for multiple comparisons testing was not adequately reflected as a confounding factor in the RoB assessment. Similarly, the issues with using significant trends in place of significant results were not adequately considered. When claiming that non-significant results can result in significant trends, the trend should be interpreted with caution (Nead et al, 2018). This is particularly true for the NTP study where the shared control groups and lack of multiple comparisons testing compound the issue, biasing toward a positive result. A more reasonable RoB assessment for the same set of studies was presented in the recent systematic review by Pinto et al. (2023). In that systematic review, the authors rated the NTP studies at a higher RoB compared to the current systematic review.

The assessment of the certainty of evidence (CoE) in the review is based on the RoB in conjunction with other factors downgrading the CoE, such as inconsistency, indirectness,  imprecision, and publication bias as well as potential factors upgrading the CoE such as a dose response. A consequence of the generous RoB assessment discussed above is that the RoB can’t have a real influence on the CoE, which ultimately brings into question the higher certainties presented in the review. Further problems arise when examining the robustness of their CoE assessment in the other domains. For example, inconsistency is another major issue across the evidence base that is downplayed by the systematic review. This problem first arises in the way the authors have chosen to synthesise their conclusions but is repeated in the CoE evaluation where non-significant results are largely ignored. Even internal inconsistencies within the NTP study are not judged as cause for a downgrade as is the case for glioma.  Another example would be schwannomas, which can occur in a few organs (e.g. salivary gland schwannomas, metastatic, trigeminal ganglion) but only occurred as a significant result in the heart. A related issue is their commentary on the variance of animal models when evaluating inconsistency for CoE. If the evidence base used different animal models, the authors stated that this did not warrant a downgrade in the CoE for inconsistency. However, they also listed this as a reason not to do a meta-analysis and these two justifications oppose each other.

The CoE assessment downplays the indirectness of the animal models and exposure magnitudes in relation to human health outcomes. RF-EMF interacts differently with smaller animals. While higher frequency RF-EMF can reach the heart or liver of a rat or mouse, it cannot do so in humans (Basandraia & Dhamia, 2016;  ICNIRP, 2020). This reduces the direct applicability of cancer outcomes in animals, particularly the schwannomas reported in the hearts of rats, to humans. Further, much of the RF-EMF exposure employed in the NTP studies was higher than the whole-body exposure limits (e.g., 6 W kg⁻¹)  ((ICNIRP, 2020; ARPANSA, 2021). Such high exposures are not encountered by people in the everyday environment and cannot be realistically associated with human cancer studies. 

The CoE assessment wrongly upgraded the certainty in the evidence for brain cancer based on a dose-response relationship with RF EMF exposure, as determined by the authors. As mentioned earlier a dose-response is reported only in the NTP (2018) study based on non-significant individual results across different exposure levels. In contrast, the recent Pinto et al (2023) systematic review did not find a dose-response relationship for brain cancer or any other tumour and did not subsequently upgrade the CoE. The ultimate consequence of the author’s systematic failings in both the CoE and RoB assessments is that results are given a higher certainty rating that is not supported by the scientific evidence.

In addition to the above major flaws there are numerous minor issues scattered throughout the document that degrade the overall article quality. These include undocumented deviations from the published protocol, reference to supplementary information that is not provided, mischaracterisation of exposure level comparisons and self-contradictions in the discussion. While the prominent issues discussed at length above have a greater impact on the interpretation of the review, the extent of additional issues complicates this interpretation and introduces significant doubt surrounding the rigour in which the substantive parts of the article have been conducted.

This review is a part of the WHO commissioned systematic review process, the overall aim of which is to assess the possible implications of RF-EMF exposure on human health. ARPANSA has therefore considered this review carefully and thoroughly when evaluating the scientific evidence regarding effects of RF-EMF exposures. In determining the impact of RF-EMF on human health the most significant evidence comes from studies on humans, not animals. This is because human observational studies are higher in the evidence hierarchy compared to animal studies as they provide more direct and relevant information about human health and disease. The WHO commissioned systematic reviews looking at observational studies in humans did not find an association between RF and any cancer (Karipidis et al 2024, Karipidis et al 2025).

In Australia, exposures to RF-EMF are covered by the Australian radiofrequency standard RPS-S1. This Australian standard was published in 2021, based on revised guidelines by ICNIRP (2020), which considered all of the relevant scientific evidence available at the time, including both the NTP and Falcioni studies. As the major conclusions of this review are primarily based on these two studies and there is no synthesis of all the available evidence, it is ARPANSA’s assessment that no new results are presented by the review and therefore no reasons for policy revisions. This systematic review on laboratory animals does not change the assessment of ARPANSA that there is no substantiated evidence of health effects from RF-EMF exposure below the ARPANSA safety limits.

Publication date:

March 2025

Published in:

Journal of Biophotonics

ARPANSA review: 

1 April 2025

Summary

This in vitro study explored the effects of blue light exposure on two types of DNA damage that are established effects of ultraviolet (UV) radiation exposure. Two different cell types were irradiated with a commercially available blue light therapy device emitting 417 nanometre (nm) wavelength light at a fixed intensity. The cells were exposed for varying durations to provide doses of blue light between 15-45 J/cm². UVB radiation was used as a positive control. After irradiation, DNA was isolated from the cells and evaluated for the two hallmark DNA malformations caused by UV radiation.  There was no evidence of DNA damage from any duration of blue light exposure. In contrast, exposure to UV radiation resulted in the formation of both types of DNA damage as expected.

Link to the study

Commentary by ARPANSA

Interest in the health effects of blue light exposure has heightened due to an increasing prevalence of LED lighting and emerging research on the relationship between blue light exposure and aspects of health like sleep (Brown, T. et al., 2022). It should be noted that the blue light emitted by personal devices is approximately 0.05-0.1% as intense as the blue light therapy device used in this study and is also of longer wavelength (Hipolito, V. & Coelho, J. 2024). This study evaluated the effect of a blue light therapy device on two types of DNA damage that are well established responses to UV radiation exposure (Mizutani, R. & Yokoyama, H., 2014; You, Y. et al., 2001). These types of DNA damage are of interest for blue light due to the proximity of the blue light wavelength (417 nm in this experiment) to the UV region of the electromagnetic spectrum (100-400 nm). 

The current study demonstrated no evidence of DNA damage from blue light exposure. Similarly, the research underpinning the effectiveness of different UV wavelengths in causing sunburn (Young, A. et al., 1998;  Diffey, B. et al., 1997) shows that, as the wavelength of light approaches the blue light region, the effects rapidly decrease.  Although this is an encouraging result, the DNA malformations assessed in this study are not the only mechanisms of DNA damage. A more generalisable measure of DNA damage such as a comet assay may have provided additional information. Other risks of exposure from light therapy devices, such as the risk of eye damage, should also be considered when evaluating their safety, and these risks should be counterbalanced against the purported benefits of exposure. ARPANSA’s evaluation on the topic of health effects from blue light exposure is that current research is inconclusive, with conflicting evidence between studies. The International Commission on Non-Ionizing Radiation Protection has released a statement (ICNIRP, 2024) recommending improvements for future study design so that the need to establish exposure guidelines can be adequately evaluated. 

Publication date:

January 2025

Published in:

Bioelectromagnetics

ARPANSA review: 

22 March 2025

Summary

This systematic review and meta-analysis assessed whether mobile phone associated electromagnetic fields (EMF) affect brain activity measurements such as resting state wake electroencephalogram (EEG) and event‐related potentials (ERP). A total of 51 studies were included in the review and 12 studies were included in the meta-analysis. The effect of EMF exposure on the outcomes of EEG and ERP measurements as well as visual and auditory discrimination was investigated. A risk of bias (ROB) assessment was undertaken for the included studies. Meta-analysis results were estimated as standardized mean difference (SMD) with 95% confidence intervals (CI). The meta-analysis showed that mobile phone exposure related to 2G significantly affected the alpha band of the EEG [SMD 0.16 (95% CI: 0.01 to 0.32)]. For the other assessed outcomes such as visual discrimination and auditory discrimination, the meta-analysis did not show significant results. The ROB assessment of the included studies mostly showed either moderate or high risk indicating some concerns. Further, a meta‐analysis for most outcomes could not be conducted due to large heterogeneity among studies. 

Link to the study

Commentary by ARPANSA:

This review and meta-analysis presented in the article indicate that EMF exposure affects the alpha band of the EEG. Alpha band oscillations are a distinctive feature of the EEG when awake and play a prominent role in human brain activity (Klimesch, 1999). However, the review and meta-analysis present some notable limitations. Some studies included in the review did not report appropriate measures of RF-EMF exposure (e.g., power density or specific absorption rate). This compromises RF-EMF characterisation in the included studies however the ROB assessment tool used in this study  does not seem to address this (Sterne et al., 2019).  The review also did not undertake a certainty in evidence assessment, which is an important aspect of a properly conducted systematic review. As noted in the article, future studies should be performed with more robust experimental designs such as adhering to the methodological standard of randomized experiments, double blinding and improved EMF exposure characterisation. Without these improvements, the scientific basis for substantiating other human physiological effects of EMF may continue to be inadequate. 

Based on the current scientific evidence, and consistent with the findings of this review, it is the assessment of ARPANSA that there is no substantiated evidence that mobile phone use (resulting in radiofrequency electromagnetic field (RF-EMF) exposures at levels below the limits set in the ARPANSA Safety Standard) cause any adverse human health effects, including in the brain.

Article publication date

8 March 2025

ARPANSA review date

March 2025

Summary

This European study reports on the creation of a new Job exposure matrix (JEM) for solar ultraviolet radiation (UVR) exposure to outdoor workers. The JEM was created by combining occupational UVR exposure measurements with estimations of the time workers spend outdoors. The exposure measurements were sourced from 12 studies published between 2005 and 2022 which detailed personal UVR exposure for 49 different occupations. The JEM estimates also included an expert assessment rating representing 3 regions of Europe based on latitude (Northern, Central and Southern Europe). The expert assessment rated the average duration of outdoor work for 372 occupations as 0, 1 to 2, 3 to 4, or ≥5 hours per workday. These exposure times were then adjusted based on latitude and on the time of the year (spring, summer, autumn or winter). This JEM will be able to be used in epidemiological studies to estimate occupational UVR exposure when participants’ work histories, and the latitude of worksites and time of year is known. 

Published in

Annals of Work Exposures and Health, 2025

Link to study

A European job-exposure matrix for solar UV exposure 

Commentary by ARPANSA

This study provides the details of the first quantitative measurement-based JEM for UVR exposure. This JEM will improve occupational assessment of UVR exposure in epidemiological studies. However, there are a number of limitations of the JEM, in particular, that 86% of included occupations are not based on measurements, but on expert assessment alone. Other JEMs that have characterised occupational UVR exposure have been solely based on expert assessment (Kauppinen et al, 2009; Peters et al, 2012) and this makes it difficult to accurately quantify exposure–response relationships in subsequent epidemiological studies.

In Australia the impact of UVR exposure has been assessed previously based on ambient UVR at specific latitudes or based on region (Green et al, 1996; Lucas et al, 2013; Sun et al, 2014). This type of exposure characterisation may not accurately reflect UVR exposure due to worker behaviours or other occupational factors. The use of a UVR JEM could improve the exposure characterisation and provide a better understanding of how occupational UV impacts diseases like skin cancer in Australia. However, a different JEM for Australian workers would be required for this purpose as this study restricts its analysis to defined latitudes of Europe. There are distinct differences in UV intensity between latitudes and also between the northern and southern hemispheres.

Australia has some of the highest rates of melanoma and skin cancer in the world and two-thirds of Australians will receive a skin cancer diagnosis of some type in their lifetime. As such, skin cancers, including melanoma, continue to constitute a large public health burden. One of the best way for Australian to protect themselves from the sun is by following the Slip, Slop, Slap, Seek and Slide messaging. More information on UV protection can be found on the ARPANSA Sun Protection factsheet. 

Article publication date

January 2025

ARPANSA review date

26 February 2025

Summary

This systematic review evaluated the association between exposure to low dose ionising radiation (LDIR) and thyroid function among occupational populations. A total of 15 studies (6 case-control studies and 9 cohort studies) published between 1997 and 2022, which included a total of 1,040,763 participants, were included in the review. The effect on thyroid function were evaluated in terms of risk of thyroid cancer, thyroid nodules, and changes in thyroid hormones. Quality assessment of the included studies was also conducted according to the Newcastle-Ottawa Scale (NOS). A qualitative evaluation of the studies was conducted to assess the effect of LDIR on thyroid function. The review showed some evidence of increased thyroid gland volume and nodule formation following the exposure to LDIR, however, this was not shown with certainty. The studies showed a reduction in triiodothyronine (fT3) and an increase or reduction in thyroxine (fT4), while thyroid stimulating hormone (TSH) level did not change following the exposure. Based on the analysis in the review, the authors conclude that even at low doses the function of the thyroid is negatively affected. 

Published in

Journal of Clinical Medicine

Link to study

Low-Dose Ionizing Radiation and Thyroid Diseases and Functional Modifications in Exposed Workers: A Systematic Review 

Commentary by ARPANSA

This review provides an evaluation of whether thyroid function changes following occupational exposure to LDIR. The findings indicate that exposure to LDIR may be a potential risk factor for some aspects of thyroid function. The study shows a few strengths and limitations, which should be considered while interpretating the findings of the review. The review presents only a narrative synthesis of results evaluating multiple health outcomes of thyroid gland e.g., cancer, nodules, and hormones in relation to LDIR exposure; and quantitative meta-analyses of the included studies were not conducted. The cohort studies included in the review had a relatively large sample size. 

The quality assessment of the included studies showed moderate quality, however, the review did not conduct a risk of bias (ROB) assessment of the included studies. ROB assessment has been regarded as an essential critical step in a systematic review to inform the findings and interpretation of the review (NHMRC, 2019). It should be noted that the NOS quality assessment involves the evaluation of the extent to which included studies were designed, conducted, analysed, and reported to avoid systematic errors; while ROB assessment involves the evaluation of bias judgments based on the quality assessment (Furuya-Kanamori et al., 2021). The review also did not undertake a certainty in evidence assessment, which is another important aspect of a properly conducted systematic review. Similarly, although the included studies represent some heterogeneity, it was not assessed in the review. For example, the included studies were conducted in diverse occupational setting (e.g., hospital, nuclear power plants, war industry, and barracks) where the approach to collecting workers’ data would have been different. The findings highlighted in the review are consistent with some comparable studies (e.g., Gudzenko et al., 2022; El-Benhawy et al., 2022; Cioffi et al., 2020). However, there are no similar data available to compare these findings in the Australian context. It is unclear if the review accounted for potential differences in calculating the dose to the thyroid; for example, changes in radiation weighting factors (e.g., ICRP60 to ICRP103), changes in dose conversion factors (e.g., ICRP68 to ICRP137) or inference of thyroid doses based on whole body monitoring. It is our assessment that there is insufficient evidence within this review to definitively conclude that thyroid function is adversely affected by LDIR.

In Australia, The Code for Radiation Protection in Planned Exposure Situations  sets out the requirements for the protection of occupationally exposed persons in all planned exposure situations. All Australian jurisdictions have uniform annual limits (20 mSv) for occupational exposure to ionising radiation. In addition to the dose limits, optimisation of radiation protection and safety involves practising ‘as low as reasonably achievable’ (ALARA) considering economic and societal factors. The Australian system for radiation protection from ionising radiation is closely aligned with international best practice as laid out in the Recommendations of the International Commission on Radiological Protection.

Date of review by ARPANSA

February 2025

Article publication date

February 2025

Summary

The International Commission on Non-Ionizing Radiation Protection (ICNIRP) have published a new document that outlines gaps in scientific knowledge that are relevant to setting limiting values for exposure to radiofrequency electromagnetic fields (RF-EMF). To maintain relevance to exposure guidelines, the ICNIRP specifically highlighted gaps in knowledge where there exists sufficient support in the scientific literature for a link between RF-EMF exposure and an endpoint and between that endpoint and health. These gaps were identified during the development of the 2020 guidelines for limiting exposure to electromagnetic fields (100 kHz to 300 GHz) and with consideration of literature that has been published since. 

The identified research gaps cover shortfalls in knowledge in various areas of dosimetry and on adverse effect exposure thresholds for eye damage, contact currents and heat-induced pain. The document also provides brief analyses on other topical areas of research related to RF-EMF and health outcomes while additionally providing justifications for why they are not prioritised in the identified research gaps.

Commentary by ARPANSA

Although research into health outcomes related to RF-EMF covers an extremely broad cross-section of various aspects of health, currently there are only a few effects that have been substantiated by the scientific literature. ICNIRP’s statement does not aim to establish new links between RF-EMF exposure and health outcomes but to further inform the numerical levels and exposure assessment methodology of the existing guidelines. Additional research investigating other health outcomes is ongoing and such research is warranted but it is not of immediate relevance to setting exposure guidelines. The state of the science in these other areas is best summarised by the set of systematic reviews that have been recently published as part of an ongoing World Health Organization project reviewing the topic.

The Australian radiofrequency standard RPS-S1 outlines limit values for RF-EMF exposure in Australia. RPS-S1 is aligned with the ICNRIP 2020 guidelines mentioned above. ARPANSA continues to monitor and evaluate research developments to ensure that the limits outlined in RPS-S1 remain fit for purpose and are aligned with international best practice. ARPANSA has research recommendations, and a research framework that informs how and what research should be conducted in Australia. These recommendations are part of the ARPANSA EME action plan that aims to promote health and safety and address misinformation about EME emissions. 

Date of review by ARPANSA

February 2025

Article publication date

1 February 2025

Summary

This study measured the personal radiofrequency-electromagnetic field (RF-EMF) exposures associated with mobile networks (including 5G) across different micro-environments in Switzerland. The exposure was measured during three different mobile use scenarios: with an inactive device (environmental), while a device is continuously uploading (max UL) and while a device is continuously downloading (max DL). The highest levels were measured during the max UL measurements, particularly in rural micro-environments. Compared to environmental exposure (e.g., median 1 mW/m² for urban business areas), exposure levels increased considerably during the max DL measurements due to the 5G band at 3.5 GHz mostly in urban areas (e.g., median 12 mW/m² in an industrial area). The highest RF-EMF levels (e.g., median 37 mW/m² in a rural centre) were observed during the max UL scenarios in rural areas. In conclusion, inducing mobile DL and UL traffic networks substantially increased personal RF-EMF exposures. 

Published in

Environmental Research

Link to the study

Exploring RF-EMF levels in Swiss microenvironments: An evaluation of environmental and auto-induced downlink and uplink exposure in the era of 5G 

ARPANSA's commentary

This study generated new knowledge by pioneering an activity-based approach to exposure assessment. The findings indicate the relevance of including near-field and far-field personal exposures to estimate cumulative RF-EMF exposures in future epidemiological studies. This has been highlighted in some recent literature (e.g., van Wel et al., 2021; Birks et al., 2021), which estimated personal RF-EMF exposures originating from near-field RF-EMF sources. A key strength of this study is that it characterized exposures associated with different types of mobile use scenarios such as no mobile phone use, and phone use with continuously downloading and uploading a file. Further, this study supports the application of its methodology to a larger European study, which is expected to provide more comprehensive exposure assessments. A notable limitation of the study is that the use of the measurement device on a specific body area to estimate the personal exposure might have resulted in some measurement uncertainties. Importantly, while mobile handset originated (i.e., auto-induced UL) exposures contributed the highest amount of personal RF-EMF exposure levels, these levels lie below the safety limits recommended by the 2020 ICNIRP guidelines and Australian standard (RPS-S1). According to the standard, the general public safety limit is 2-10 W/m² depending on the operating frequency of telecommunication infrastructure. RF-EMF exposures in Australian public environments are generally far below the limits given in the standard (Henderson et al., 2023; Bhatt et al., 2024). The standard is designed to protect people of all ages and health statuses from the adverse health effects of exposure to RF-EMF exposures. Furthermore, it is ARPANSA’s assessment that such low-level RF-EMF exposures do not pose any health risk in populations.

Date of review by ARPANSA

30 January 2025

Article publication date

13 January 2025

Summary

This in vivo study explored the effects of high power 28 gigahertz (GHz) radiofrequency electromagnetic fields (RF-EMF) on the ocular response and corneal damage threshold of rabbit eyes. Thirty-five male rabbits were first anaesthetised and immobilised before their right eyes were exposed to RF-EMF (28 GHz) for 6 minutes with power densities ranging from 2 to 7.5 kW/m². The corresponding left eyes were not exposed and served as controls. The eyes were assessed prior to exposure and at 10 minutes, 1, 2 and 3 days following exposure. 

No eye damage was observed at incident power densities of 3 kW/m² and below. Some types of eye damage were observed beginning at 3.5 kW/m² with their prevalence increasing with power density. The study estimated that the threshold for eye damage from a 6-minute exposure to 28 GHz RF-EMF is between 3.5 and 3.8 kW/m².

Published in

Health Physics

Link to study

Investigation of the Ocular Response and Corneal Damage Threshold of Exposure to 28 GHz Quasi-millimeter Wave Exposure 

ARPANSA's commentary

RF-EMF at high power levels can heat biological tissue which can lead to heat-related damage. The eyes are particularly sensitive to RF heating. In their 2020 RF safety guidelines, the International Commission on Non-Ionizing Radiation Protection (ICNIRP, 2020) acknowledge a shortage of studies that use sufficiently high power to cause heat-induced injury.  The lack of information on eye damage thresholds was also recently reiterated in an updated knowledge gap analysis document (ICNIRP, 2025). These types of studies are considered difficult to conduct because they must be carefully designed in order to remain within the bounds of ethical guidelines for animal research (ARVO, 2024) while still providing relevant information. 

This study pioneers knowledge in this area by exploring how high-power 28 GHz RF-EMF may cause eye damage, establishing a threshold level for cornea damage. Together with other studies by the same research group on higher frequencies (Kojima et al., 2018; 2020; 2022), this body of research provides more clarity on the levels at which RF-EMF causes damage to the eyes. Such research on eye exposure is important for frequencies above 6 GHz due to the fact that RF-EMF at these frequencies is mostly absorbed on the outer surface of the skin or eyes (Sasaki et al., 2017).

In Australia, exposure to RF-EMF is governed by the Australian radiofrequency safety standard RPS-S1. Under the standard, exposure of the general public to RF-EMF at 28 GHz is restricted to 10 W/m² for whole body exposure and 30 W/m² for localised exposure. These levels are far below the threshold for ocular damage estimated by this study, confirming the effectiveness of RPS-S1 for protecting against the adverse effects of RF-EMF.