Saturday, March 10, 2012

Measuring Absorbed Dose: An Instructive Conversation

Gottagetoffthegrid was commenting on the article: "Radioactive iodine exposure in thyroid up to 87 millisieverts" from Thyroid screenings detect relatively high exposure"

Gottagetoffthegrid notes: "This value is essentially useless without the activity (measured in becquerels)in the organ.

Absorbed dose in Sv is dependent on a number of assumptions including distance from the source. it is proportional to the inverse square of the distance, actually. meaning if you half the distance to the source you quadruple the dose.

The standard method of calculating absorbed dose is to assume the organ is 50cm to 100cm from the source. so the actual absorbed dose coud be 100 to 1000 times higher since the thyroid is only 3 to 4cm diameter."

A Green Road Replies:
 "Agree, what is the internal dose per kilogram, usually measured in Bq? By avoiding the usual and standard way of stating radiation exposure, they avoid any responsibility, consequences as well as allowing people to take measures to protect their children and families.

Again, this is another spin or disinformation on top of media propoganda, that there is no harm with internal low dose radiation.
This is right out of the playbook that apologists use,
[end quote]

Majia responded:
"Very instructive comment

So, the 40 millisieverts projected by the US DTRA (the Defense Threat Reduction Agency) as the annualized dose to the thyroid of a 1 year old California kid... (

COULD be much HIGHER for many reasons beyond this projected dose of 40 millisieverts only includes Iodine-131 (No Cesium, strontium, plutonium, etc)...

Anyone else on the west coast getting rather worried?"

[end quote]


1 comment:

  1. I recall an article by a female professor from Ottawa, Ontario, Canada which was rather authoritatively describing why there is no such thing as a 'safe' dose : linear response being a fiction unsupported by science. Checking I note too much information for convenient linking in comments. Let me know if you encounter difficulty reading the file. I am thinking is the person I had in mind.