Re: background vs man-made emmissions

["Sandy Perle" <sandyfl@earthlink.net>]

> It seems to me that radiation is not just radiation is some of it gets concentrated in
> different body parts like teeth and bones, or thyroid.

Your interpretation is a bit off, and let me explain. Radionuclides 
migrate and accumulate in specific body parts, or, are simply 
passed through the body, based on the chemical characteristics, 
not because of the radioactive emissions. Iodine is found in the 
thyroid, and therefore, when the body has an uptake of I-131 (for 
example) it migrates to the thyroid. It is for this specific reason that 
I-131 is used for both diagnostic and therapeutic procedures. Sr-90 
accumulates in the bone, such as Calcium does. Now, what about 
the radiation aspects of this. Each radionuclide decays and emits 
specific types of radiation. Each organ is exposed to a specific 
amount of radiation based on the type of emission, and obviously 
the total dose is based on the time the organ is exposed. The 
science is that whether the organ is irradiated from within, due to 
internal deposition, or externally, due to whole body irradiation, the 
effect on the organ is the same. That is why the industry is 
regulated based on total dose, called TEDE (Total Effective Dose 
Equivalent)> The total dose from external added to the internal. It 
doesn't matter where the dose originated. So, if there is no internal 
irradiation, the entire dose is due to external. This is what we are 
all exposed to from natural background, terrestrial, internal 
radionuclides, etc.

In essence, there is no difference from radiation exposure. The only 
difference is from internal deposition, and where the radionuclides 
accumulate. The effect though is the same as if the exposure was 
due to external sources.
----------------------------------------------------------------------------------
Sandy Perle					Tel:(714) 545-0100 / (800) 548-5100   				    	
Director, Technical				Extension 2306 				     	
ICN Worldwide Dosimetry Division		Fax:(714) 668-3149 	                   		    
ICN Biomedicals, Inc.				E-Mail: sandyfl@earthlink.net 				                           
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Costa Mesa, CA 92626

Personal Website:  http://www.geocities.com/capecanaveral/1205
ICN Worldwide Dosimetry Website: http://www.dosimetry.com
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