Thursday, December 1, 2011

Radiation: What We Know



What we know:

Yesterday, Phoenix’s Beta Counts per Minute was 700 CPM according to radnet

Now let us look at EPA responder guidelines

I. EPA’s Emergency Response Air Monitoring Guidance Tables 2009 edition

This manual instructs emergency responders to consult with a health physicist when radiation levels are at 3 times background

The occupational action level is 300 CPM beta or 10 microsieverts an hour


II. Turnbacks Guidance Final MOU November 2007 Memorandum of Understanding on Radiation Turnback Levels for EPA Personnel Responding to Radiological Emergencies

[paraphrasing] This documents stipulates that exposure must not exceed 500 millirem during 1 year.

500millirem is 5 millisieverts of exposure. 

In certain emergency conditions, the document states that workers can be exposed to higher amounts if they sign waivers. Waivers are deemed necessary because they are assuming risk.

Workers are supposed to turn back at 10 rem per hour of gamma exposure during the early stages of an emergency and 1.5 rem an hour during the intermediate phase of an emergency [end paraphrasing]

Majia here: One hour of 10 rem is 100 millisieverts! That means emergency responders in these types of emergencies would be sacrificing their health to assume control of the emergency.

What do we know about cancer risks at various levels of exposure?

Here is 1 important study I posted about a couple of weeks ago.

Here is the study and the relevant finding: For every 10 millisieverts of low-dose ionizing radiation, there was a 3% increase in the risk of age-and-sex adjusted cancer over a mean follow-up period of 5 year

Cancer risk related to low-dose ionizing radiation from cardiac imaging in patients after acute myocardial infarction. By Mark J. Eisenberg MD MPH, Jonathan Afilalo MD MSc, Patrick R. Lawler MD, Michal Abrahamowicz PhD, Hugues Richard MSc, Louise Pilote MD MPH PhD http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3050947/pdf/1830430.pdf

[Excerpted] The cumulative exposure to radiation from cardiac procedures was 5.3 milli     Sieverts (mSv) per patient year, of which 84% occurred during the first year after acute myocardial infarction. A total of 12 020 incident cancers were diagnosed during the follow-up period. There was a dose dependent relation between exposure to radiation from cardiac procedures and subsequent risk of cancer. For every 10 mSv of low-dose ionizing radiation, there was a 3% increase in the risk of age- and sex-adjusted cancer over a mean follow-up period of five years (hazard ratio 1.003 per milliSievert, 95% confidence interval 1.002–1.004).
         
 



1 comment:

  1. Radiation
    Great post.Thanks for sharing the information and links.Well i have a site for complete radiation solution.I think it will help you.

    ReplyDelete