Radiation literature survey

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Summary:

This in vivo experimental study examined the impact of radiofrequency electromagnetic fields (RF EMF) exposure on the expression and immune cell production on rats. Rats were split up into 3 groups, two of the groups were exposed to RF EMF at frequencies of either 1.5 or 4.3 gigahertz (GHz) and with a power density of 100 W/m2 for 6 minutes. The third group were exposed to both frequencies for 6 minutes each. The authors reported statistically significant changes in expression and number of immune cells at 6 hours, 7 days and 14 days post exposure compared to rats not exposed to RF EMF. Similarly, a statistically significant increase in the expression of cytokines at 6 hours and 7 days was noted. The study concluded that RF EMF could cause immune suppression at the given exposure. 

Immune Responses to Multi-Frequencies of 1.5 GHz and 4.3 GHz Microwave Exposure in Rats: Transcriptomic and Proteomic Analysis

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The high level of RF EMF exposures used in the study would not be generally encountered by the public in the everyday environment. The exposure level used in the study is up to 13 times that of the maximum permissible whole body public exposure level (7.5 - 10 W/m2) (RPS S-1). Given the high exposure employed in the study the reported effects may have been due to heating. 

Previous studies have looked at the effects of RF EMF exposure on the immune system and conflicting results have been reported (Ohtani et al 2015, Yao et al 2020). The overall evidence of the impact of RF EMF on the immune system has been reviewed by Public Health England’s Independent Advisory Group on Non-ionising Radiation. This review concluded that there is no compelling evidence that exposure to low level RF EMF has an adverse effect on the immune system (HPA, 2012). Further, in reviewing the scientific literature overall it remains ARPANSA’s conclusion that there is no substantiated evidence that RF EMF exposure, below the limits set in RPS S-1, causes any health effects, including effects on the immune system. 
 

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The Sun Safe app (iOS) was co-developed by the authors, teenagers, Australian sun health promotion experts, researchers, and digital health developers with the aim of improving sun health knowledge and promoting sun safe practices amongst adolescents. This pilot study aimed to test if the use of the Sun Safe app improved sun health knowledge and behaviour of teenagers (aged 12-13 years). A total of 51 participant completed the study conducted in Western Australia. The participants were split into 2 groups, the placebo group (n=25) which had access to the SunDial app (which notifies the user when sunrise and sunset events occur) and the Sun Safe group (n=26) which had access to the Sun Safe app. Participants completed questionnaires on sun health and knowledge and rated the quality of the app via survey. Improved sun health knowledge was observed in participants given the Sun Safe app, however, they also experienced significantly more sun burn events (relative risk 1.7, 95% confidence interval 1.1, 1.8). The Sun Safe app was rated well by users (average 4.2/5).

The Effects of Using the Sun Safe App on Sun Health Knowledge and Behaviors of Young Teenagers: Results of Pilot Intervention Studies

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The results of this pilot study found that the Sun Safe app participants were more likely to experience sun burn events but also had improved sun health knowledge. This may potentially be a confounding association as it is possible that following a sun burn event participants were more likely to seek information from the Sun Safe app which in turn improved their sun health knowledge. The study has several limitations including its small number of participants, the non-blinding of participants and potential confounding. Further research is required to assess the effects of the Sun Safe app on sun health knowledge and sun-protective behaviour. The Australian Cancer council also has its own app, the SunSmart App, that provides sun protection information and information on the UV levels across Australia. For more information on sun protection please view the ARPANSA sun protection webpage available here.

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This case series study examined the clinical features of laser pointer related injuries to the eye in children in the UK. A total of 9 children (aged 9-15 years, with injuries to 12 eyes), admitted for eye injuries induced by laser pointers were recruited into the study. All children were healthy prior to injury. Of the 9 children, 3 had deteriorating vision when examined while the remainder were asymptomatic but were referred to the clinic by optometrists who noted incidental macular changes. Exposure to a laser pointer was confirmed in 8 of the 9 cases. The patients were followed up for an average of 25.6 months following the initial referral. The structural macula changes persisted in all cases at follow up, and in one case there was progression in the macula lesion size. The authors conclude that although children may present as asymptomatic there can be permanent structural damage to the macula following a laser pointer exposure to the eye. This can progressively get worse and result in further complications.

The Danger of Laser Pointer–Induced Retinal Damage in Children: A Large United Kingdom Case Series and Survey of Public Awareness

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All laser pointers that are available to the Australian public must have a power output of less than 1 milliwatt (1 mW). Lasers with an output below this are considered safe for accidental exposure due to the low risk of injury to the eye. Protection from laser pointers that comply with this limit occurs as a result of the human instinct called the ‘aversion response’. Laser pointers with power output above 1 mW are prohibited for importation into Australia under the Customs (Prohibited Imports) Regulations 1956. Unfortunately, Australian studies have shown that handheld laser pointers available to the public are not always labelled correctly and may emit energy at harmful levels above 1 mW. In one study, the majority of laser pointers imported into Australia when tested failed to meet the output restriction with outputs well above 1 mW (Wheatley, 2013). ARPANSA is providing advice on laser safety on its website to promote risk awareness and assist in responsible use of handheld laser products. ARPANSA is also working with online marketplaces to address the issue and in particular to facilitate sellers’ compliance with existing regulations. 

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In Australia, 95% of melanomas and 99% of non-melanoma skin cancers are attributed to overexposure to ultraviolet radiation. This review examined the last 40 years of sun protection policies and achievements in Australia and suggested the need for further action. The cancer prevention program started in 1981 with mass-media campaigns featuring the Slip, Slop, Slap message and an evidence based SunSmart program. Australian sun protection policy has evolved over the years and initiatives like taking the GST tax off sunblock and early childhood sun protection programs have been introduced. However, in Australia skin cancer remains the most common type of cancer and the incidence of non-melanoma skin cancer is greater than all other cancer types combined. The authors state that sun protection policy makers have become complacent and more work needs to be done.  They suggest that future sun protection policies should focus on a comprehensive media campaign, robust data collection and implementing regulatory measures to safeguard children. The review concluded that these measures offer the best opportunity to consolidate the current sun protection programs and protect future generations from preventable skin cancer. 

Forty years of Slip! Slop! Slap! A call to action on skin cancer prevention for Australia

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Australia has one of the highest rates of skin cancer in the world. At least two in three Australians will be diagnosed with skin cancer by the age of 70. The major cause of skin cancer is exposure to ultraviolet (UV) radiation from the sun. However, UV induced skin cancer is almost entirely preventable. It is important that all Australians are aware of the damages of UV exposure from the sun and high-profile awareness campaigns have been the backbone of how Australians have been informed of this danger for the last 40 years. 

One of the best sources of information on sun protection and skin cancer is the Cancer Council website. The Cancer Council provides information of skin cancer causes, prevention, diagnosis, screening, and early detection. The major sun protection messaging that both ARPANSA and Cancer Council still promote is the Slip, Slop, Slap Seek and Slide as it can provide a high level of UV protection. However, it is still good to be out of the sun in the middle of the day when the UV is at its peak. 

ARPANSA operates UV monitors that provide real time data on UV levels for cities across Australia. These monitors make up the ARPANSA UV Network and this information can been found on the ARPANSA Ultraviolet Radiation Index webpage. This UV data is also collected and displayed by news organisations and can be found on the Cancer Council website. More information on UV protection can be found on the ARPANSA Sun Protection factsheet.  
 

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This paper reviewed studies on the risk of cancer or benign neoplasms following low or moderate doses of ionising radiation in utero or in childhood from medical and environmental sources. The literature search identified 60 studies that were included in this review and meta-analyses were conducted. The review found excess cancer risks associated with both in utero and childhood exposures. For childhood exposures this occurred at low radiation dose levels of less than 0.1 Gy, and for in utero exposures this occurred at levels around 0.02 Gy. This review was mainly focused on leukaemia but also found evidence of an increased risk in brain/central nervous system cancers, as well as thyroid cancer. The authors conclude that childhood cancer risk is increased in the low radiation dose range of less than 0.1 Gy. These findings are further supported by a separate review conducted by Little et al. on medical diagnostic radiation exposure in early life without quantitative estimates of dose which reached a similar conclusion (a review of this study by ARPANSA can be accessed here).

Review of the risk of cancer following low and moderate doses of sparsely ionising radiation received in early life in groups with individually estimated doses

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Moderate and high doses of ionising radiation at high dose rates are known to be associated with an increased risk of cancer. However, this review presents evidence of an increased risk of cancer at low radiation doses (less than 0.1 Gy). Special concern in relation to radiation protection is afforded to children, and women of child-bearing age with most diagnostic radiology procedures posing little risk to the mother or foetus. The Code for Radiation Protection in Medical Exposure (2019) (RPS C-5) sets out the Australian requirements for the protection of patients, including pregnant women and children, relating to their exposure to ionising radiation. While the (Little et al) study’s meta-analysis supports a statistically significant increase in cancer risk for low radiation exposure, the increase is very small, and the risks should be assessed against the benefits of having the procedure. ARPANSA advises parents concerned about their children’s exposure from radiological procedures to talk to the doctor requesting the radiological procedure. The child’s doctor and the staff at the radiology facility should work together on which tests are required and evaluate the risks and benefits in each child’s individual circumstances. If there are still questions at the radiology facility, these can be raised with the radiology team during the consent process before the imaging proceeds.

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This nested case-control study evaluated the association between occupational exposure to extremely low frequency magnetic fields (ELF-MFs) and electric shocks and risk of lymphoma within the Nordic Occupational Cancer Cohort of Nordic populations (Finland, Iceland, Norway, Denmark and Sweden). The study included: cases of non-Hodgkin’s lymphoma (NHL, n=68,978), chronic lymphocytic leukaemia (CLL, n=20,615) and multiple myeloma (MM, n=35,467) diagnosed during 1961 – 2005. Each case was matched to five controls by year of birth, sex and country. Occupational exposure to ELF-MF and electric shocks was assessed using job-exposure matrices. The results of the study demonstrated no increased risks of these cancers among workers exposed to high levels of ELF-MF for NHL (Odds ratio (OR): 0.93; 95% confidence interval (CI) 0.90 – 0.97), CLL (OR: 0.98; 95% CI 0.92 – 1.05) or MM (OR: 0.96; 95% CI 0.90 – 1.01). Similarly, no increased risk of these cancers was reported for exposure to electric shock in occupational workers as the ORs were 0.94 (95% CI 0.91 – 0.97) [NHL], 0.93 (95% CI 0.87 – 0.99) [CLL], and 0.97 (95% CI 0.93 – 1.02) [MM]. The authors concluded that the study found no evidence of an association between occupational exposure to ELF-MFs and electric shocks and lymphoma risk.

Malignant lymphoma and occupational exposure to extremely low frequency magnetic fields and electrical shocks: a nested case-control study in a cohort of four Nordic countries

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Unlike some previous studies, including an Australian study, showing a mild association between occupational exposure to ELF-MFs and the risk of NHL in a few occupational groups, this latest study demonstrates no association. Compared to most of the previous study designs, this study adopted improved methods (e.g., inclusion of a larger number of cases, ascertainment of cases accurately and with nearly complete follow-up of study participants) to investigate this potential relationship. Therefore, the results of this current study provide improved reliability with reassuring findings of no risk. There seems to be a knowledge gap regarding whether occupational exposure to electric shocks increases the risk of lymphoma. This study presents the first evidence of no elevated risk of the disease associated with the exposure to electric shocks. Consistent to current international scientific consensus, it is the assessment of ARPANSA that there is no link between occupational exposure to ELF-MF and any cancer, including those investigated in this study.

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This systematic review and meta‑analysis, which included 30 eligible studies, assessed the relationship between exposure to mobile phone radiofrequency (RF) radiation and headaches in humans. The results showed that RF exposure from mobile phone base stations was not associated with headache, with Odds ratio (OR) of 1.14 (95% CI 0.75, 1.52). However, the authors did report that RF radiation emitted from mobile phones was associated with headaches, OR = 1.30 (95% CI 1.21–1.39). This risk was similar for younger people and adults and also for longer or shorter durations of mobile phone use. The authors concluded that RF radiation from mobile phones was associated with headaches. 

Mobile phone electromagnetic radiation and the risk of headache: a systematic review and meta‑analysis

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Overall, this study reports that exposure to mobile phone RF radiation increases the risk of headache by up to 41%. Though the finding is in line with that of a previous systematic review and meta-analysis report (Wang et al., 2017), the results of these systematic reviews and meta-analyses should be interpretated cautiously. For example, the latest report only included three good quality studies, whereas most of the other included studies were either poor or fair quality. The quality of the study is also related to how well RF exposure to mobile phone was measured (e.g., self-reported vs quantitatively measured) and/or whether or not potential confounders were accounted for. For example, almost all studies included in the report employed self-reported RF exposure, which is only a substitute measure of actual RF exposure and hence likely to be inaccurate. The self-reported data on mobile phone use employed by most of these studies generally gives rise to error (i.e., recall bias) in RF exposure estimation. This, together with possible confounders unadjusted for in the studies, affects the potential relationship between mobile phone RF exposure and headache. These important methodological issues indicate that the review and meta-analysis process was not of good quality and likely resulted in providing biased findings.

It is the assessment of ARPANSA and international organisations such as The World Health Organisation (WHO) and The International Commission on Non-Ionising Radiation (ICNIRP) that there is no established scientific evidence to support that RF exposure when using a mobile phone causes headache. 
 

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This longitudinal study assessed radiofrequency (RF) radiation population exposure in 13 countries, including Australia. A mobile phone-based tool (Electrosmart™ App) was used to collect data on 254,410 mobile phone users’ downlink RF exposure (i.e. received radio signal strength) to mobile phone base stations, and Wi-Fi/Bluetooth networks over the period of three years (2017 to 2020). The study showed that Wi-Fi and Bluetooth contributed most of the total measured RF population exposure; and the exposure to these sources seemed to increase over time. However, the exposure levels recorded were orders of magnitude lower than regulation limits in each of the countries.

Longitudinal study of exposure to radio frequencies at population scale

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Overall, the paper reported that the measured RF exposure levels were much lower than the Australian and international public exposure limits. Of note, the study methodology utilised to ascertain population RF exposure is not quite accurate as the App, in fact, measured the background downlink RF exposure. Further, it provides no information on how the measured background RF exposure represented the population RF exposure. In order for the measured background RF exposure to be represented as the ‘population exposure’, the study participants (i. e., mobile phone users) should place the phone close to the body during the whole time when RF exposure was measured. Therefore, the reported RF exposure can only be a surrogate measure of population exposure and hence, the findings of this study should be carefully interpreted. 

ARPANSA has conducted RF measurement studies around mobile phone base stations and published the results on the ARPANSA website. In 2017, ARPANSA published a study assessing the RF exposure level due to Wi-Fi in Australian schools. Exposure levels from other RF sources such as mobile phone base stations, radio, and TV broadcasts were also measured. Overall, the exposure levels from all RF sources measured were much lower than the public exposure limits in the Australian RF Standard. There remains no substantiated scientific evidence that exposure to RF EMF below the limits in the Australian RF Standard causes any adverse health effects. 
 

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The UK Million Women Study is a prospective cohort study examining the association between mobile phone use and brain tumours in women. The study initially recruited 1.3 million women born from 1935 to 1950. Between 2001 and 2013, 776 156 women completed surveys on their mobile phone use every 3-5 years. Of these, 489 769 women reported using a mobile phone. The study found no overall increase in the risk of brain tumours in women using mobile phones compared to women that never used one (risk ratio 0.97, 95% confidence interval = 0.90 to 1.04). Furthermore, the study also found no risk of brain tumours among mobile phone users when assessed by brain tumour subtype, different levels of mobile phone use or duration of use for at least 10 years. The authors concluded that the use of mobile phones does not increase the risk of brain tumours in women. 
 

Cellular Telephone Use and the Risk of Brain Tumors: Update of the UK Million Women Study

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The results of this study are consistent with the results of a similar study and the only other prospective cohort study that has examined the association between mobile phones use and brain cancers, the Nationwide Danish cohort study. The Danish study divided the entire adult population of Denmark aged 30 and older into two groups - those who had a mobile phone subscription between 1990 and 2007, and those who didn’t. The Danish study reported no association between having a mobile phone subscription and brain tumour risk, even after at least 13 years of subscription. Similar findings were reported by an Australian study (a population-based ecological study) which found no increase in the incidence of brain tumours during 1982 to 2013. During this time there was a large increase in the number of mobile phone subscriptions in Australia (Karipidis et al, 2019). 

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This paper reviewed studies on cancer risk from medical diagnostic radiation exposure in utero, and postnatal stages of life where radiation quantitative dose estimates were not available. The type of procedure (e.g. fluoroscopy, CT scan, X-ray etc.) gives a general indication of the likely dose involved but this is not as informative as studies that include data on the actual doses received. The literature search identified 89 eligible studies that were included in this review and meta-analyses were conducted. This review found multiple studies that yielded statistically significant excess cancer risks due to in utero and postnatal exposure to medical diagnostic radiation. Significantly higher risk estimates were found for leukaemia, lymphoma, central nervous system (CNS) tumours and any other cancer in the meta-analysis for in utero exposure. This is mainly due to earlier studies which found more significant excess risk than later studies. The reduced excess risk in later studies could be explained by the progressive decrease in foetal dose per X-ray examination due to advances in radiographic technology. For postnatal exposure, significant excess risks were more apparent in later studies, particularly CT scan studies. The postnatal meta-analysis found statistically significant excess risks for leukaemia, CNS tumours and any other cancer outcomes. This data strengthens the evidence for a carcinogenic effect of low dose radiation exposure in utero. However, the interpretation of the postnatal exposure findings is more difficult due to the possibilities of reverse causation (i.e. conditions predisposing to cancer lead to an increase of radiation imaging) biasing the results. Subsequently, this reduces the strength of a causal interpretation for postnatal exposure.

Cancer risks among studies of medical diagnostic radiation exposure in early life without quantitative estimates of dose

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In Australia, the system for radiological protection draws on international best practice, particularly, the International Commission on Radiological Protection (ICRP) and the International Atomic Energy Agency (IAEA). Special concern in relation to radiation protection is afforded to children, and women of child-bearing age. Most diagnostic radiology procedures pose little risk to the mother or foetus. However, interventional radiology procedures, and CT scans of the abdomen or pelvis may result in an elevated foetal dose, and an increased risk of cancer. With the continuing advancement of the use of ionising radiation in medicine, it is important that safety guidance represents contemporary best practice. The Code for Radiation Protection in Medical Exposure (2019) (RPS C-5) sets out the Australian requirements for the protection of patients, including pregnant women and children, relating to their exposure to ionising radiation. It is ARPANSA’s goal to ensure that the highest standard of protection is made available through the implementation of the relevant Codes and Safety Guides. These safety materials give practitioners in diagnostic and interventional radiology a best practice approach to their day-to-day clinical work. While the (Little et al) study’s meta-analysis supports a statistically significant increase in cancer risk, the increase is very small and the risks should be assessed against the benefits of having the procedure. ARPANSA advises parents concerned about their children’s exposure from radiological procedures to talk to the doctor requesting the radiological procedure. The child’s doctor and the staff at the radiology facility should work together on which tests are required and evaluate the risks and benefits in each child’s individual circumstances. If there are still questions at the radiology facility, these can be raised with the radiology team during the consent process before the imaging proceeds.