question on PET radioisotope production in reactors

["Jaro" <jaro-10kbq@sympatico.ca>]

Dear Radsafers,



Perhaps one or two of you can help me answer this question, please.



A friend provided the following reference recently (see below), about the

production of the popular PET radioisotope fluorine-18 using a two-step

nuclear reaction which starts with an (n,alpha) reaction, in a fission

reactor (as opposed to the standard method of production using >20 MeV

protons from a cyclotron, by way of 18O(p, n)18F ).



I would be interested in a comparison of the reaction rates in the two

production methods, as well as information on whether nuclear medicine labs

equipped with small reactors have used them for PET radioisotope production

(and if not, why not ?).

The reason I'm asking is that it seems to me that if one can get both PET

and neutron-activated radioisotopes from one source - a reactor (at those

labs that have one) - then the cyclotron would appear to be superfluous.



Thank you very much, in advance.



 Jaro

http://www.cns-snc.ca/branches/quebec/quebec.html





-----Original Message-----

Sent: Friday December 19, 2003 11:06 AM

To: 'Franta, Jaroslav'

Subject: RE: cyclotrons vs reactors ?



FYI, I found a PET isotope prescription (F18) in an old reference.



In the document by W.E. Downs and D.J.R. Evans entitled "Slowpoke - A

mini-reactor for activation analysis", AECL Commercial Products, Research

Division, CPSR-327 (June 1971) [to bepresented at the 2nd symposium on

recent developments in neutron activation anslysis - Churchill College,

Cambridge, Jue 28, 1971 to July 1, 1971], we find the following double

nuclear reaction (p. 12):



Li6(n,alpha)t

O16(t,n)F18



"Irradtaion of a saturated solution of 6Li2+ in acetic acid (5 ml) allows

for the preparation of up to 20 mCi of F18 in a single irradiation. The

separation protocol proposed by Dworkin and Lafleur may be applied to the

irradiated solution."



Ref: H.J. Dworkin, P.D. Lafleur, "Radioactive Pharmaceuticals", p. 635,

USAEC CONF 651111, 1966.

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