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Radiation Safety Training

‘Balancing ALARA and Reality in Radiation Training’

Adapted from a presentation given at the Health Physics Society Joint Meeting February 2002

Introduction

Radiation risk is either totally unknown or poorly understood by the general population; the almost universally accepted misconception (regardless of age, sex, nationality, educational background, etc.) is that ionizing radiation is more dangerous than other, more mundane hazards, such as chemicals, mains electricity, or road travel.

So the first goal must be to inform, in a way that can be easily understood. One technique involves comparison with mundane risks. The additional purpose is to clarify and correct, as far as it is possible, the false impression of ‘deadly-at-all-times’ radiation. Traditional Radiation Safety training seems, albeit unintentionally, to reinforce this misconception, and assumes a basis of specific technical understanding that does not always exist in the world.

Unknown Hazard

When there is no significant previous knowledge, this is a golden opportunity to create an accurate, basic, understanding of a risk which has not been previously encountered. This is essential, to allow the individual to respond to a variety of circumstances with appropriate precautions, neither under- nor over-estimating the risk involved.

Though significant events are very rare, they must be identified and dealt with promptly. In contrast to routine circumstances, such events could result in serious injury or death. A particular difficulty is that the hazard may be contained in an innocuous welded steel container just a few millimetres or so long, and that contact with such a source will not cause immediate pain, so no natural physical warning feedback exists. Serious injury or death can result from contact or near-contact exposures of a fraction of a second with such sources (e.g. sources used for industrial radiography).

Degrees of Danger

Replacing misinformation and hysteria with facts presented in an understandable and believable manner will allow misconceptions to be laid aside, and help prevent actions which might create a problem where none exists, or turn a mild incident into a hazardous or expensive event.

Inconsequential situations must be identified and their potential for absorption of resources, personnel and time neutralized, otherwise they will divert finite resources from more significant risks, resulting in an increased likelihood of workers, visitors and the public being subjected to avoidable harm. It is not conservative to announce the presence of an exaggerated hazard, as that will prevent or reduce the chance that real and present dangers are addressed.

A radiation training program has to balance the requirements of teaching, encouraging and enforcing observance of existing regulations, with a reasoned perspective on risk. It is not enough to provide the occasional in-service on this, instead, it must be integrated into the entire course. Contrary to yet another misconception, openly admitting that the ‘traditional approach’ is not based on scientific data, being only an administrative convention, is not only allowable but essential to a good understanding.

Our biggest challenge is to provide a suitable education to students, researchers, staff, contractors and the public – persons with a huge range of education, from doctorate levels to those with minimal technical knowledge – to allow all of them to act appropriately in the event of significant situations. For example:

  1. A lost industrial radiography source;
  2. A major fire in a nuclear medicine department;
  3. A bombed irradiation facility

In contrast, trivial events much be recognized as such. For example:

  1. Standing a few feet away from an industrial radiographer carrying a source projector;
  2. Working in a laboratory near x-ray cabinets;
  3. Finding a ionizing radiation smoke detector with a cracked plastic casing

New Perspective to Counter Misconception

To successfully teach a new perspective on radiation safety, the first requirement is to understand why most prospective course attendees (even those with the smallest awareness of radiation) come equipped with these misconceptions. This is due to five major factors:

  1. The inability of the human body to detect ionizing radiation by any of the five senses (sight, sound, hearing, taste, smell or touch);
  2. The portrayal of ‘Superheroes’ in popular fiction (e.g. the Incredible Hulk, Spiderman, and Superman) portraying radiation as an almost magical power or curse that can cause instant, horrific mutations and / or frightening reductions or increases in physical strength;
  3. The official guidance-body description of radiation as harmful at all levels down to zero. (Popularly known as the Linear, No-Threshold (LNT) Hypothesis).
  4. Some so-called ‘Green’ environmental groups, which exaggerate and / or embellish the risks of radiation, making it appear out of proportion to the myriad other risks of existence, and usually on an emotionally charged platform.
  5. The awesome image of the atomic mushroom cloud, and all it represents.

Factor 1

The inability of the human body to detect ionizing radiation by any of the five senses can only be addressed by artificially augmenting those senses. An effective course has, as its first prerequisite, the acquisition, familiarization with, and regular use of sensitive radiation detection equipment. This equipment must be sufficiently sensitive to detect background radiation, so that the attendees can ‘get a feel’ for the reality of natural radiation. Everyday items that display measurable radiation fields will be used to illustrate the ubiquitous nature of radiation, (Fiestaware, potassium chloride (salt substitute), granite kitchen or bathroom finishes, etc.) [With regard to background radiation, it must be emphasized that, in the natural radiation ‘soup’ in which we reside, each human is subject to more than 60,000 radioactive ionisations internally every second, (more than 200 million per hour) and that a typical chest X-ray is about equivalent to ten days of average natural background radiation, or four hours of high end (but still natural) background radiation.] The use of radiation detection equipment during routine tasks will also be encouraged.



As for the second and third points, the following quotes from the Advisory Committee on Radiological Protection, one of the guidance organizations of the Canadian Nuclear Safety Commission (CNSC), document ACRP-18 show these to be

Factor 2

- The idea of radiation as a magical curse – totally wrong (at levels of normal use and all except extremely high levels, only attainable by close exposure to nuclear explosions, inside irradiation facilities, etc.);

Factor 3

The LNT Hypothesis – unlikely, at best, or just plain wrong:

"It is clear that we do not know if low doses of radiation at low dose rate have any harmful effect on the health of humans." ACRP-18, p.18

"The assumption of linearity may be quite appropriate for practical purposes in radiation protection even though it may not always be the best model for the relationship between dose and any particular effect." ACRP-18, p.19

"Since there is no direct proof that exposure of adults to 10-20 mSv per year for a few years causes any harmful effects on health, it is strongly recommended that any detrimental health effects calculated using the linear non-threshold hypothesis for radiation exposures of adults in this region or lower should be referred to as hypothetical health effects only." ACRP-18, p.19 (emphasis in original)

In addition, some scientists and organizations are now stating very clearly that the LNT hypothesis is wrong:

Lovelace Respiratory Research Institute Research Debunks Radiation Phobia (2011)

Bruce Power 2008 Report on Radioactivity in the Environment (see page 5)

Factor 4

Pressure groups that focus on one aspect of risk or prejudice to the exclusion of all others are not unique to radiation, but are found in many fields. The facts and thought-provoking perspectives presented as an integral part of the course must show the flaws of an emotionally based approach that ignores logic.

Factor 5

The imagery of the atomic mushroom cloud is hard to place in perspective. Everyday images are used to help. E.g. a comparison of the relationships:

  • Changing the battery of an ionizing radiation smoke detector
    • > Standing a few feet outside shielded vault
      • > Standing a few feet from a radioiodine-treated thyroid cancer patient
        • > Working with a nuclear medicine patient dose
          • > Standing a mile from a "mushroom cloud"
  • Standing near a cold pop can
    • > Spray drift-back when walking past a lawn sprinkler
      • > Spilled cup of water

        • > Walking in a rain shower with an umbrella
          • > Being a mile downstream from the collapse of the Teton dam
  • Being near (electrically powered) sound amplifiers at a concert
    • > Touching the terminal on a car battery
      • > Riding on bumper cars at an amusement park
        • > Plugging in toaster to wall socket
          • > Being hit by a lightning strike
  • Sitting on an (operating) microwave oven
    • > Sitting in a truck with a Citizen’s band radio
      • > Using a cell phone
        • > Sitting below a microwave transmitting (TV, etc.) repeater tower
          • > Inches in front of an (operating) radar transmitter on a warship

Emphasize again the government-sponsored message of ACRP-18 (and other such groups)

  1. There is no evidence of harmful effects at low dose / low dose rate
  2. The LNT hypothesis has been convenient simply because it could be used to develop regulatory limits, i.e. it is an uncomplicated formula to which the data has been fitted.
  3. t would be wrong to even consider assessing the radiogenic risk of doses below 100 mSv, (i.e. to estimate potential deferred induced cancers) as such an assessment would inevitably be used to justify spending real funds to fix hypothetical health risks. [See: Health Physics Society Position Statement "RISK ASSESSMENT&" (1995). "The Health Physics Society recommends that assessments of radiogenic health risks be limited to dose estimates near and above 10 rem" (100 mSv). Also: American Nuclear Society, Policy Statement, April 1999, Health Effects of Low-Level Radiation: "It is the position of the American Nuclear Society that there is insufficient scientific evidence to support the use of the Linear No Threshold Hypothesis in the projection of the health effects of low-level radiation."]

Radiation Safety Training Program

The program must be designed to meet the requirements of the regulator, and, at the same time, inform the exposed workers that incredibly cautious regulatory limits should not be taken to indicate that radiation is more hazardous than other hazards encountered in the work environment or in the home. In fact, radiation is unique among the hazards of a technological society, in that its negative effects are delayed (a low probability of leukemia –1 or 2 years after a radiation dose, or more than ten years later, for other cancers), or non-existent (unless exposures far greater than those allowed by the regulations occur) whereas other hazards tend to be immediate (biohazards, chemical hazards, electrocution hazards, drowning, asphyxiation physical injury hazards, etc).

The primary goals for the program are

  1. a realistic perspective on risk, and
  2. a knowledge of the principles and practices needed to effectively manage radiation exposure within regulatory requirements.

Students and staff must understand that where radiation exposures of more than 20 mSv per annum are predicted, pre-engineering of time (occupancy of surrounding areas), distance (room layout) and structural shielding factors must be used to ensure the predicted exposures are below the regulatory limits. Two, rather contradictory factors must be considered:

  1. Pre-engineering is more cost-effective than modification – i.e. adding extra shielding after construction.
  2. If the design criteria are unrealistically conservative, these would result in reduced exposures far below the regulatory limits, and the appropriation of funds that would otherwise be available for more practical and cost-effective uses.

Therefore, a careful balance of realistic criteria with a margin for error of less than an order of magnitude should be used for designing new facilities.

Where radiation exposures of more than 1 mSv per annum are the norm, the basic philosophy used is the ALARA principal (As Low As Reasonably Achievable, economic and social conditions being taken into account). For these facilities, the ALARA principle means exposures that are not likely to approach the regulatory limit of 20 mSv (2 rem) consistently [i.e. over a five year period, so as to approach the five year limit of 100 mSv (10 rem)] do not need to be reduced – unless the expense to achieve this reduction is negligible – as otherwise it would be a case of spending real funds to fix hypothetical health risks.

Where radiation doses are expected to be lower than 1 mSv (100 mrem) per annum, standard procedures and protocols are used, and further reductions in exposure are never considered, as they are neither necessary, nor could they ever be considered cost-effective.

It is of prime importance that all authorized and designated radiation workers understand that there is no evidence that radiation exposures below 100 mSv per year have detrimental effects, and considerable evidence {albeit not officially accepted by some key advisory bodies, such as the International Committee on Radiological Protection (ICRP)} that low level, low dose rate radiation may have beneficial effects.

Teaching the ALARA Principle without Teaching Paranoia

A not uncommon result of teaching the ALARA principle (As Low As Reasonably Achievable), economic & social conditions taken into account) is over-emphasis on reduction of dose, no matter how low it already is.

However, the course must, in accordance with local regulations (e.g. the Canadian Federal Radiation Protection Regulations, section 4) meet the requirement that:

"Every licensee shall implement a radiation protection program and shall, as part of that program,

  1. keep…. the effective dose and equivalent dose received by and committed to persons as low as reasonably achievable, social and economic factors being taken into account, through the implementation of
    1. management control over work practices,
    2. personnel qualification and training,
    3. control of occupational and public exposure to radiation, and
    4. planning for unusual situations; and
  2. ascertain the quantity and concentration of any nuclear substance released as a result of the licensed activity
    1. by direct measurement as a result of monitoring, or
    2. if the time and resources required for direct measurement as a result of monitoring outweigh the usefulness of ascertaining the quantity and concentration using that method, by estimating them."

These requirements (however phrased in each country’s regulations) exist because large exposures to "ionising radiation" can result in various types of injury. The so-called non-stochastic effects or certainty effects are dependent on the magnitude of the dose and will not occur unless the dose of radiation is orders of magnitude greater than the "regulatory limits". However, some other types of injury, called "stochastic effects [chance effects, the severity of which is independent of the dose] have been assumed by the ICRP and government regulators to have a low but non-zero probability of occurrence even at doses below the regulatory limits. In fact, it is the official position of these organizations that any dose of radiation is potentially capable of producing stochastic effects, no matter how small the dose.

Their position is that the probability that a harmful "stochastic" effect will occur depends on the dose received; the smaller the dose the less the chance of it occurring (and thus causing harm), and that this relationship is linear and has no threshold [aka the Linear, No-Threshold hypothesis (LNT)]. The consequence of this position, if accepted, is that it is desirable to avoid all unnecessary exposures to radiation and to keep doses from any necessary exposures as low as reasonably achievable.

Our modification of this position accepts the requirement to meet regulatory limits and to reduce non-radiation worker radiation exposures when these may approach the radiation worker limits (20 mSv) but requires that some consideration be given to the expense of any dose reduction measures. If dose reduction can be achieved with minimal expense (for example, during construction of shielded rooms) then reductions from the 20 mSv range down by a factor of up to ten may be considered. If significant expense is anticipated, the policy will be to ensure that exposures are maintained within the 20 mSv limit, as averaged over five years. (Justification: Ref. ACRP-18)

Thus the facility considers that the requirement that:

"Every licensee shall establish, implement and maintain procedures designed to maintain doses of radiation as low as reasonably achievable, social and economic factors being taken into account."

- is met by the facility Radiation Safety manuals and associated documentation.

The "social and economic factors" to be taken into account include making certain that the costs of reducing the doses from a given level to a lower level are no higher than the expenditures that are generally made for reducing a unit of occupational or public risk associated with other industrial, medical and social activities. Factors such as the loss of employment if the dose had to be reduced to such low levels that a course of action would have to be discontinued will also be considered as sufficient to cancel any proposed modification of an activity, unless the dose would exceed the limit for radiation workers. In other words, if the proposed additional measures increase the time or the funds required for the activity to the point where it might be considered too expensive, those measures would not be taken. Of course, the facility holds to the position that, regardless of economic and social considerations, it is mandatory that no person be exposed to radiation at levels in excess of the regulatory dose limits.

In practice, where radiation exposures are sufficiently close to the limit for NEWs or RWs, both individual and collective doses may sometimes be considered when deciding what levels of dose are as low as reasonably achievable for a given operation. Efforts devoted solely to minimizing collective dose will not normally be considered, as they inevitably raise expenses unjustifiably (there being no solid evidence that radiation at levels below or near the regulatory limits has any detrimental effect, and considerable evidence that such radiation levels are beneficial).

Three Tenets

Three internationally accepted philosophical approaches are followed by the facility:

  1. No practice shall be adopted unless its introduction produces a positive net benefit;
  2. All exposures shall be kept As Low As Reasonably Achievable, economic & social conditions being taken into account (ALARA);
  3. The dose equivalent to individuals shall not exceed recommended maximum limits.

Part b) (ALARA) has already been addressed earlier in this document and is again, from a more practical viewpoint, hereafter. Parts a) and c) are so fundamental as to require no more explanation here.

The three fundamental principles of radiation protection – time, distance and shielding, will continue to be the means by which the facility maintains exposures ALARA. All procedures will first have been reviewed and approved, indicating that any radiation exposure incurred has been evaluated and assessed as acceptable:

  1. Time – ‘Dry runs’ should be used to prepare for actual work with radiation. The intent of this is to minimise exposure to radiation, and to ensure that no work is done without a thorough prior understanding of the steps required and the difficulties involved. On no account should the procedure be rushed, as this may lead to errors and is not necessary to maintain safety.
  2. Distance – The inverse square law provides a simple, effective and generally cost-neutral means of greatly reducing radiation exposure, and should be used when possible. If the approved procedure to be implemented requires the staff member to stay close to the source, the radiation exposure incurred should not be considered a cause for concern.
  3. Shielding – Where shielding is provided, is effective, and can be used without negatively impacting the procedure to be followed, it should be used. Again, if the approved procedure makes the use of shielding impracticable, this should not be considered a cause for concern.

Cautionary Notes:

It is imperative that the course participants understand that the decision to use the ALARA principle in the process of following procedures does not imply that there are significant radiation hazards involved in these procedures. As long as established procedures are followed, the potential for negative health effects is minimal or non-existent.

Hazards may be encountered if established procedures are not followed. A cavalier or complacent approach to radiation safety is never acceptable, and has been the cause for incidents of significant contamination and exposure, and even injury and death. It is all a question of balance.

The facility is determined to maintain this very challenging balance, and requires that procedures, training, exposure records and commitment to established tenets be reviewed periodically, and adjusted as appropriate, in pursuit of this very worthy goal.

Conclusion:

It is hoped that this modified approach to radiation safety training will:

  1. Improve the understanding of radiation risks
  2. Reduce the level of unreasonable fear or apprehension about radiation
  3. Encourage a more open-minded attitude to the use of radiation
  4. Reduce the diversion of finite resources from more significant and certain risks
  5. Decrease the likelihood that an option will be rejected in therapy, diagnosis, power generation, or research, purely because it involves radiation.

References (Further reading and Quotes):

  1. Biological Effects of Low Level Exposures, School of Public Health, University of Massachusetts, Amherst. Web site: www.belleonline.com
  2. Radiation Protection Dosimetry, A Radical Reappraisal, J.A. Simmons, D.E. Watt, Medical Physics Publishing, Madison, Wisconsin 1999, 140pp.
  3. Radiation, Science, and Health Inc. Web site: http://www.radscihealth.org/rsh/
  4. NRC Advisory Committee on Nuclear Waste reported its recommendations on "Health Effects of Low Levels of Ionizing Radiation": "Some studies in the U.S. as well as in China, Sweden, Poland and Canada have arrived at conclusions that do not support the LNT model. Other research concludes that it is likely that at least a threshold or perhaps beneficial risk decrements (hormesis) exists at lower doses."
  5. NCRP Report No. 136 (NCRP 2001) concludes with a very weak affirmation of the linear-non threshold (LNT) model of radiation risk based on a rather selective review of the literature (Page 211): "In conclusion, although the evidence for linearity is stronger with high-LET radiation than with low-LET radiation, the weight of evidence, both experimental and theoretical, suggests that the dose-response relationships for many of the biological alterations that are likely precursors to cancer are compatible with linear-non threshold functions. The epidemiological evidence, likewise, while necessarily limited to higher doses suggests that the dose response relationships for some, but not all, types of cancermay not depart significantly from linear-non threshold functions. The existing data do not exclude other dose-response relationships. Further efforts to clarify the relevant dose-response relationships in the low-dose domain are strongly warranted." (Emphasis added to words that indicate equivocation.)
  6. American Nuclear Society, Policy Statement, April 1999, Health Effects of Low-Level Radiation: "It is the position of the American Nuclear Society that there is insufficient scientific evidence to support the use of the Linear No Threshold Hypothesis in the projection of the health effects of low-level radiation."
  7. Health Physics Society Position Statement "RISK ASSESSMENT" (1995). "The Health Physics Society recommends that assessments of radiogenic health risks be limited to dose estimates near and above 10 rem" (100 mSv)
  8. Lovelace Respiratory Research Institute Research Debunks Radiation Phobia

Canadian Analogy:

1. The following analogy, created for members of the Canadian Radiation Protection Association (CRPA) attempts to explain why concerns about the implications, if that organisation were to officially acknowledge the non-linear effects of low level radiation and beneficial uses of radiation, are unsound. Such an acknowledgement is wrongly perceived to indicate a bias in favour of the Canadian Nuclear Society, which promotes the use of things radioactive or even the nuclear industry itself: "Let’s discuss, instead of the CRPA, an imaginary organisation - the CVPA, (the Canadian Vitamin Protection Association). Of course, the main focus of the CVPA should be the danger of overdosing on vitamins, and we must be sure to not come out and state that low levels of vitamins are actually healthy, in case we are accused of being in the pocket of the CVS (Canadian Vitamin Society), or even the pharmaceutical companies themselves."

Note: This approach to radiation training is not ideal, but is not as scare-inducing as traditional training, and will have to suffice until the regulations are changed, allowing the benefits of increased radiation levels to be accessible to all who wish to enjoy them.

See Professor Wade Allison's arguments on this, as recorded in The Australian:
Professor Wade Allison, as reported in the Australian news.

See also another link relating to his position on radiation exposure: