Radiation and the Standard Banana

Watt's Up With That, home of the global warming resistance, had a highly interesting post up about how to explain radiation to non-specialists using the concept of the Standard Banana.  The Banana Equivalent Dose, or BED, is the amount of radiation equivalent to exposure to one ordinary banana - "roughly 520 picocuries per 150g banana".  No, this is not due to some radiation exposure by evil banana barons, this is perfectly natural and a consequence of all that potassium they contain.  Radiation is, actually, natural.  Cosmic rays zip through you every day, even if you eat organic, free-range vegetables and vote Democrat. 

I had to undergo radiation safety training as a consequence of my work for several years, every year, and wore a film badge to measure radiation exposure.  The government concept of ALARA, As Low As Reasonably Achievable, was developed in the very early days of radioactive science when they really didn't know that much, except that too much would kill you.  Later they noticed a trend in cancer vs. radiation exposure.  BUT!  The way they looked at it, you had only so much radiation exposure, of any kind, and once you hit the red line of cumulative dose it was Cancer City.  However actual experiments about low dose radiation seems to indicate there is a baseline below which no damage occurs, even cumulative.  (To be more precise, damage that does occur is easily and completely repaired.)

The topic of radiation damage in the human body is fascinating, and still not completely understood.  Exposure from exterior sources vs. ingestion, type of particle emitted, and even organ exposed all make a difference in calculating damage and the chance of three-headed children.  Also, individual response can vary widely.  For example, some people appear to be able to flush radioactive material from their bodies before it has time to do much damage.  The celebrated case of Radithor, a patent medicine made with radium in the 1930s, is an example.  When one patient died, rather horribly, from the effects of radiation damage, the doctor who had prescribed it testified in his defense that he had taken just as much of the medicine himself and was still healthy so the medicine could not be the cause of death.  The patient in question had taken large amounts  (three bottles!) of Radithor every day, possibly because one of the side effects immediately after a large, damaging dose of radiation is a feeling of increased energy.  Since one of the *longer-term* side effects is usually death, most people doing the risk-benefit analysis would opt out.

(For those of you playing at home, the Snarkatronic Computational Array estimates that one bottle of Radithor had a Banana Equivalent Dose of nearly 2 million bananas.  Don't say you weren't warned.)