The production of F-18 on low flux reactors

Conference · Wed May 01 04:00:00 EDT 1985 · J. Nucl. Med.; (United States)

OSTI ID:7054071

Neuder, M; Eckelman, W C; Channing, M; Larson, S M

The production of fluorine-18 in oxygen-containing lithium compounds occurs by neutron irradiation of lithium in the reaction /sup 6/Li(n,..cap alpha..) /sup 3/H, /sup 16/O(/sup 3/H,n) /sup 18/F. The neutron flux available in most research reactors is on the low end of the range of 10/sup 12/-10/sup 14/ n/cm/sup 2//s, and therefore attaining the maximum yield per gram of lithium is important. Since high surface area to volume ratios are optimal, the effect of minimizing sample thickness on the yield of F-18 was studied. Using quartz tubes varying in diameter from 1 to 4 mm (i.d.), a series of irradiations were conducted with lithium carbonate and hydroxide. Results indicated that the 1 mm i.d. tube yielded the highest activity of fluorine per gram of lithium sample, while progressively lower activities were measured for the large diameter tubes. Thus, the same mass in 4 x 1mm tubes produced 180% of the activity produced with the same mass in one 3mm tube. Using 3 x 2mm tubes increased the yield over the same mass in one 3mm tube to 136%. Although it might be assumed that the use of larger amounts of lithium in a single tube would yield specific activity increases, the activity actually measured will be substantially lower. Such differences can be attributed to sample self-shielding effects. Expressed in terms of geometry-dependent self-shielding factors relating the average flux in the sample to the flux incident on the sample, a 1 mm i.d. tube has an associated theoretical self-shielding factor of .646 while that for a 3mm i.d. tube is .336. A flux of 10/sup 14/ n/cm/sup 2//s produces 90 mCi F-18 in 2 h using 0.4 g /sup 6/Li/sub 2/CO/sub 3/ in one 3 mm tube. Using the appropriate geometry, then, clinically useful amounts of F-18 can be produced in reactors of relatively low flux.

• Research Organization: National Institutes of Health, Bethesda, MD
• OSTI ID: 7054071
• Report Number(s): CONF-850611-
• Conference Information: Journal Name: J. Nucl. Med.; (United States) Journal Volume: 26:5
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
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62 RADIOLOGY AND NUCLEAR MEDICINE
ALKALI METAL COMPOUNDS
BARYON REACTIONS
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
CARBON COMPOUNDS
CARBONATES
FLUORINE 18
FLUORINE ISOTOPES
HADRON REACTIONS
HOURS LIVING RADIOISOTOPES
HYDROGEN COMPOUNDS
HYDROXIDES
IRRADIATION REACTORS
ISOTOPE PRODUCTION
ISOTOPE PRODUCTION REACTORS
ISOTOPES
LIGHT NUCLEI
LITHIUM CARBONATES
LITHIUM COMPOUNDS
LITHIUM HYDROXIDES
NEUTRON FLUX
NEUTRON REACTIONS
NUCLEAR REACTIONS
NUCLEI
NUCLEON REACTIONS
ODD-ODD NUCLEI
OXYGEN COMPOUNDS
RADIATION FLUX
RADIOISOTOPES
REACTORS