Mineral neutron activation

Dennis D Patton dpatton at azstarnet.com
Thu Dec 5 09:30:47 EST 1996


In article <5843kv$ru0 at newsstand.cit.cornell.edu> aq12 at cornell.edu (Antonio Quiñones) writes:
>From: aq12 at cornell.edu (Antonio Quiñones)
>Subject: Mineral neutron activation
>Date: 4 Dec 1996 14:59:43 GMT

>It's my understanding that, upon irradiation of humans with neutrons 
>(purposefully or by accident), the minerals in the body (Ca2+, for 
>example) will be activated and will emit radiation in their decay 
>process.
>(if this is incorrect please do correct me.  I am also assuming that 
>neutron activation is the only way to activate minerals by 
>irradiation).

>My questions:

>Q.1.)   Does anyone have a list of the predominant minerals in 
>the human body that would become activated upon irradiation with 
>neutrons?

The principal ones are: (stable isotope, natural abundance, neutron reaction, 
product, half-life)

	sodium-23 (100%) (n,gamma) -> Na-24 (15 hr)
	chlorine-37 (24%) (n,gamma) -> Cl-38 (37 min)
	calcium-48 (0.2%) (n,gamma) -> Ca-49 (8.7 min)
	phosphorus-31 (100%) (n,gamma) -> P-32 (14.3 d)
	nitrogen-14 (99.64%) (n,2n) -> N-13 (10 min)
	iodine-127 (100%) (n,gamma) -> I-128 (25 min)

All of the products are gamma emitters and can be detected from outside the 
body using a whole-body counter or equivalent.  See for example Kennedy N et 
al: Normal levels of total body sodium and chlorine by neutron activation 
analysis.  Phys. Med. Biol. 1983: 28:215-221, or Leroy Booth's chapter on NAA 
in Henkin RE et al [eds]: Nuclear Medicine. Mosby, 1996, pp 156-158.

>Q.2.)   What are the half-lives of these activated minerals? (see above)

>Q.3.)   Could these internal emissions (from the activated 
>minerals in decay) be detected at the surface of the individual's 
>skin? (see above)

>Many thanks

>Antonio Quiñones
>aq12 at cornell.edu

Dennis D. Patton MD
Division of Nuclear Medicine
University of Arizona, Tucson




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