Re: Dose Correlation

[Jim Durham <jsdurham@lamar.colostate.edu>]

According to Hall, in Radiobiology for the Radiologist, other analogies
can be made.  He notes that

"...a total-body dose of 4 Gy of x-rays given to a human is lethal in
many cases.  This dose represents an absorption of energy of only about
67 calories, assuming the person to be a 'standard man,' weighing 70
kg.  ...  Converted to heat it would represent a temperature rise of
0.002 degrees C, which would do no harm at all;  the same amount of
energy in the form of heat is absorbed when drinking one sip of warm
coffee.  Alternatively, the energy inherent in a lethal dose of x-rays
may be compared with mechanical energy or work:  it would correspond to
the work done in lifting a [standard] man about 16 inches from the
ground.
    Energy in the form of heat or mechanical energy is absorbed
uniformly and evenly, and much greater quantities of energy in these
forms are required to produce damage in living things.  The potency of
x-rays [or other radiation], then, is not so much of the total energy
absorbed as of the size of the individual energy packets."

The analogy is interesting, but it is inappropriate when applied to
health effects.

Jim Durham
Radiological Health Sciences Department
Colorado State University
jsdurham@lamar.colostate.edu

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