Sievert is a unit of ionizing radiation risk. It is not a unit of dose. Ionizing radiation dose in Gray must be converted to Sievert to obtain risk. Risk in Sievert is confined to risk of cancer.

Other biological effects for ionizing radiation require reference to risk in Gray. 

There is no advantage to attempting to force non-ionizing radiation risk to conform to ionizing radiation risk. 

Thanks! This may require new strategies to define / quantitate biological effects by non-ionizing radiation. Personal level heteromorphism in electrosensitivity may be a reality which needs to be studied.

Sonal

Yes. New strategies are needed. Defining dose and measuring dose are critical. The definition of dose must include a mode of measurement. Ionizing radiation has depth and directionality complications that make dose to a tissue or organ very imprecise. Regulatory rules were established that defined dose to a location, but are impractical to perform. Gross simplifications are used for practicality. Practice is usually more simplified. The only recourse is to restrict exposure to ionizing radiation. Determining dose after an exposure is difficult. Designing experiments to deliver dose is difficult. The same problems apply to non-ionizing radiation. Add to that heteromorphism and the difficulties multiply.

It is better if researchers develop a method of dose measurement that is independent of regulatory measurement. The Sievert is arbitrary. The Gray has arbitrary components, but is based on energy deposited in tissue. Both units are regulatory definitions.

I agree with Alvarez. To quantify the harmful effect for non-ionizing radiation we have to define quantities similar to radio biological effectiveness or quality factor as is done for ionizing radiations. Such quantities are derived using epidemiological data and judgement. Absorbed dose for non-ionizing radiations can be obtained in terms of  joule/kg. But the next step is very uncertain with no available data.

I also mostly agree with Joseph. However, depending on the penetration depth of the radiation (which, of course, is dependent on its wavelength) it might not be meaningful to try to convert these units into the Gray/Sv systems (J/kg) but maybe more promising to take the W/m2 as the measure and to define effectiveness/quality factors to arrive at a quantitiy analogous to Sv.

The biological effects of ionizing radiation have been distinctly quantified for high levels of dose ranges. Above approximately a whole body dose equivalent of 100 mSv, the effects are detectable by chromosome aberration analysis. For still higher dose levels, various deleterious effects are discernible. For example,1 Gy acute whole body exposure can cause radiation sickness and can cause temporary sterility in males. The effects for higher doses are also reported up to 3-4 Gy of acute whole body exposure which is the LD 50(60). Partial body exposure effects such as skin erythema, epilation, cataract are also well-known. A large amount of information on stochastic and deterministic effects have been published by ICRP and other bodies which, after due consideration, also stipuiate the maximum permissible effective doses for radiation workers and population. 

The biological effects of non-ionizing radiations (RF, microwaves, etc),unlike ionizing radiations, are not fully established and quantified. Several effects have been reported for persons residing near mobile phone base stations. These include neurological complaints, sleep disturbances, fatigue, discomfort and nausea and even DNA and genetic damage. The literature is flooded with papers on these effects but these are not proved. Considering these, in India, the ICNIRP limit levels before September 2012 (4.5 - 9.2 W/m2 ) have been reduced by one-tenth. How many patients are undergoing physiotherapy treatment using RF and microwave radiation in hospitals throughout the world for pain relief,etc. and how many workers are involved in the maintenance work of the antenna-towers? Their exposures are very much higher than the permitted levels. I am not aware of any data on the biological effects on these persons.

It is likely, here, that the thermal effects are more pronounced than non-thermal effects. Ionization produces free radicals which result in radiation damage.

Now coming to your question, the mechanisms of biological effects on human tissues are completely different for ionizing and non-ionizing radiations. The Sv is a unit of dose equivalent. It represents the stochastic health risk which for radiation dose assessment is defined as the probability of cancer induction and genetic damage. The W/m2  is the incident energy flux. The earlier unit of radiation exposure, roentgen, also can be expressed in terms of energy flux for a particular photon energy. But roentgen applies only to x-and gamma radiation. The dose equivalent in Sv takes into account all other types of radiations, such as charged particles and neutrons and there are different weighting factors for different radiations/energies. These concepts cannot be extended to non-ionizing radiations.

I hope I have elucidated the point but would like to elicit your response for further discussion.

It might be interesting to study the biological effects of the very high powered over-the-horizon (OTH) radar systems that were popular in the past. Examples include the "woodpecker" installation near Chernobyl (10MW) and the Gabala Radar Station in Azerbaijan (300 MW). 

1. Both are MKS units , so easy to convert.

2. Non ionizing means indirectly ionizing, like gamma and neutrons. Transport of gamma through matter also produces radiation damage. You can use quite a few MC codes. Some of them are available to India some are banned. 

If we find too interesting problem, we can help in providing MC simulation from our JA-IPU code for both gamma and neutrons. This is because preparation is required for each problem.

I am sorry you are incorrect. Ionising radiation includes both directly ionising (charged particles such as alpha particles and protons) AND indirectly ionising radiations (gamma rays and neutrons). Please read any book on Nuclear Physics or Physics of Radiation Therapy. All radiations with energies below UV (which are also ionising) in the electromagnetic spectrum of radiation are considered as non-ionising radiation.

Besides, since the biological effects are entirely different, you cannot do a simple conversion between these radiations. See my comments above.

Note to Ms Sonal Rajiv Bakshi: In my earlier comments above, it may be added that the unit roentgen is defined in terms of ionisation in air. But air and tissue have the same effective atomic number: Air = 7.64 and Tissue = 7.42. This explains why the radiation monitors for x-and gamma radiation are still using the old roentgen unit. We can safely assume roentgen, rad and rem are nearly identical. But the exposure units can be applied only up to 2 MeV or so.  

I agree with UV . I meant that ionization is due to charged particles. Neutron and gamma produce charged particles then it is indirectly ionizing. Several books have mentioned this . Strength of ionization by UV must be very weak compared to a charged particle. We normally focus on its excitation effects. But by definition you are right. In text books also we teach Bethe Bloch relation in name of ionization effects. UV must also be taught.

Thanks, will try to find the book, must be very useful for basics, am curious and keen to do something about this. The Department of Telecommunication and Cell phone manufacturers do give a limit of 6 minutes per day, that means beyond 6 minutes something is happening! Would like to know what is it and how is that determined, matter of right type of expertise coming together  I think. Thanks a lot for sharing.

Dr J.M. Godfrey, Your respected father, Dr L.D. Marinelli, reminds me of the Marinelli beaker he had designed for estimating the activity radioactive liquids, such as I-131 in urine, either with the GM or scintillation counter, with good counting efficiency; also his research work with great illustrious scientists, G.Failla, Edith Quimby, John Laughlin and others in the famous Memorial Sloan Kettering Cancer Center. Since I joined BARC in 1960, I have been in touch of their foundation work in radiological and nuclear medicine dosimetry. The Radiation Dosimetry book edited by Hine and Brownell was our bible at that time.

Is it possible to scan and send on-line the Dosimetry chapter of the Encyclopedia contributed by your father? Regards.

I join you in requesting this chapter too. Good to see reminisces. Back to basics may help getting or making  the method for non ionizing radiation.

Dear Dr.J.M.Godfrey,

It is indeed a kind gesture on your part to transmit the abstract of your fathers's dosimetry article abstract to RG. You may please send the full text to my Apple email address:

[email protected].

The input box will have sufficient memory to accomodate this lengthy article. I hope this will be OK for you.

Thanks and regards.

I originally chose not to reply to this question due to the amount of content and controversy from this topic mostly arising from oversimplification. I am just now commenting since I think it's important to answer the original question. This type of relation between ionizing and non-ionizing will have to consider the different endpoints of these radiations outside of cancer, which seems to be the major focus in most publications. When a more detailed consideration of endpoints is applied, identical biological endpoints can be compared between ionizing and non-ionizing radiation (as any other agent) exposures. Generally for ionizing radiation, this is termed a Relative Biological Effect (RBE) where varying doses (J/kg) for the same endpoint are given as a ratio between different radiation types. Non-ionizing exposure may be quantified in these units (J/kg) as well, particularly when the SAR (W/kg) or power density is available.

RF radiation can cause the blood-brain barrier to become damaged, which can correlate to several secondary effects especially to the central nervous system. Additionally, Ionizing radiation has been known to effect cognitive performance and physiological parameters and higher dose levels. Tests varying exposures over a similar endpoint such as cognitive performance can be made. Unfortunately, most of these exposures tend to be in the very exposure range and data is limited to primates and rodents. http://www.ncbi.nlm.nih.gov/pubmed/20550949

 Dear Dr. Godfrey

Kindly share the full chapter with me, may be via Dropbox? It has been very educative, with so may responses. Thanks!

Dear Dr. S. Ananthnarayanan

Thanks for the details, I took long to read all the responses. Atomic number of Air and Tissue, am not very clear, will try to find out. Human tissue composition will not be same for muscle and bone for example, hence am wondering how this number is determined.

Non ionizing radiation may be evaluated in terms of thermal and non thermal effects and not similar to ionizing radiation looks like.

If you have received the Chapter, kindly share Dropbox link on [[email protected]]

Thanks 

Content of tissue and bone may be supplied by the ICRU. U.S. NIST has this information on the web.

http://physics.nist.gov/cgi-bin/Star/compos.pl?matno=262

http://physics.nist.gov/cgi-bin/Star/compos.pl?refer=ap&matno=119

Very novel sources of information, thank you very much Dr. John FM.

The mass energy absorption coefficient of air/tissue and water (related to effective atomic number) are nearly equal for x and gamma rays up to 2 MeV. 1R of exposure corresponds to an energy absorption of 0.869 rads in air and nearly 1 Rad in tissue. The energy flux for non-ionizing radiations expressed in SAR (Watt/gm) can be converted to equivalent exposure in roentgens/rads. But the comparison stops here. We know the discernible effects on humans of x-and gamma rays above 10R.  For other ionizing radiations, we have to take into account their QF as well.  But the effects of non-ionizing radiation are not known with certainty even for higher exposures. The experimental studies on mice and monkeys are for very high exposures, as pointed out by  John Flores-McLaughlin and these cannot be extrapolated to humans. We can take only proved end-points for comparison. The studies on humans for ionizing radiation effects have a long history and a variety of detrimental effects have been actually observed. I feel we can make a start by doing  statistical cytogenetic studies on consenting healthy patients in hospitals commencing  physiotherapy with RF and microwave radiation. The tests should be done after the treatment as well, allowing sufficient days for recovery.  I am sure just as cancer patients recover after radiotherapy, physiotherapy patients will also come to normal (perhaps faster) after some period. Depending on the sample size, one can come to some conclusive results.

I have received the article (26 pages) on Dosimetry, kindly scanned and transmitted to me by Judith Marinelli Godfrey. It deals with radioactive decay, standardization of radioisotopes, clinical dosimetry (including internal dosimetry) using beta and gamma emitters, etc. It was not meant to be an article dealing with non-ionizing radiation. As such, there is no mention of NIR in this article. If you still need it, I shall forward these pages to you. Please note there is some difficulty in deciphering the text due to scanning and transmission losses (Ms Godfrey, please note). Also, I have to request her to re-send one of the sets which got erased while opening.

We have done preliminary studies in cell phone users, and exposure of cell cultures to cell phone radiation in vitro for cytogenetic endpoints. Thanks for the excellent suggestions and explanation. Once you get a better copy, kindly share and oblige.

Hi,

The content of tissue and bone may be supplied by the ICRU , ICRP and NIST has  this information on the web.

Yes, as mentioned by John Flores-McLaughlin, NIST gives this information. Thanks