친전자성 치환반응을 위한 [18F]F2 Gas의 생산 연구 (Production of [18F]F2 Gas for Electrophilic Substitution Reaction) |
Author |
문병석1,김재홍1,이교철1,안광일1,천기정1,2,3,전권수1, |
Byung Seok Moon, M.S.1, Jae Hong Kim, PH.D.1, Kyo Chul Lee, Ph.D.1, Gwang Il An, Ph.D.1,Gi Jeong Cheon, M.D. & Ph.D.1,2,3, and Kwon Soo Chun, Ph.D.1 |
Affiliation |
원자력의학원 RI 및 방사성의약품개발실1, 핵의학연구실2, 핵의학과3 1Laboratory of Radiopharmaceuticals, 2Laboratory of Nuclear Medicine, 3Department of Nuclear Medicine, Korea, Institute of Radiological and Medical Sciences (KIRAMS), Seoul, Korea |
Abstract |
Purpose: Electrophilic [18F (T1/2=110 min) radionuclide in the form of [18F]F2 gas is of great significance for labeling
radiopharmaceuticals for positron emission tomography (PET). However, its production in high yield and with high specific
radioactivity is still a challenge to overcome several problems on targetry. The aim of the present study was to develop
a method suitable for the routine production of [18F]F2 for the electrophilic substitution reaction. Materials and
Methods: The target was designed water-cooled aluminum target chamber system with a conical bore shape. Production
of the elemental fluorine was carried out via the 18O(p,n)18F reaction using a two-step irradiation protocol. In the first
irradiation, the target filled with highly enriched 18O2 was irradiated with protons for [18F production, which were adsorbed
on the inner surface of target body. In the second irradiation, the mixed gas (1% [19F]F2/Ar) was loaded into the target
chamber, following a short irradiation of proton for isotopic exchange between the carrier-fluorine and the radiofluorine
absorbed in the target chamber. Optimization of production was performed as the function of irradiation time, the beam
current and 18O2 loading pressure. Results: Production runs was performed under the following optimum conditions: The
1st irradiation for the nuclear reaction (15.0 bar of 97 % enriched 18O2, 13.2 MeV protons, 30 μA, 60-90 min irradiation),
the recovery of enriched oxygen via cryogenic pumping; The 2nd irradiation for the recovery of absorbed radiofluorine
(12.0 bar of 1% [19F]fluorine/argon gas, 13.2 MeV protons, 30 μA, 20-30 min irradiation), the recovery of [18F]fluorine for
synthesis. The yield of [18F]fluorine at EOB (end of bombardment) was achieved around 34±6.0 GBq (n>10). Conclusion:
The production of [18F electrophilic agent via 18O(p,n)[18F reaction was much under investigation. Especially, an aluminum
gas target was very advantageous for routine production of [18F]fluorine. These results suggest the possibility to use [18F]F2
gas as a electrophilic substitution agent. (Nucl Med Mol Imaging 2006;40(4):228-232)
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Keyword |
[18F]fluorine, aluminium target, electrophilic substitution, PET |
Full text Article |
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