For more than a year,124I (T=4.15 d) has been produced routinely with a compact cyclotron by irradiation of124TeO2 with 14 MeV deuterons, followed by dry distillation of the iodine radioisotopes formed from irradiated target materials. The following by-products have been measured and compiled in each charge: 13.2-d123I, 60-d125I, 13.0-d126I, 12.4-h130I and 8.02-d131I. The data show that after 45 h decay time, the sum of the activities of these nuclides is less than 5% of the124I activity. Observation of this limit has been required by the Swiss Regulatory Agencies for a PET study of cell proliferation in human brain tumors using [124I] IUdR.
A fast and easy method for the preparation of radiolabeled 5-halo-2-deoxyuridine (halo=[76Br], [123I] and [211At]) is presented. Labeling is accomplished by oxidation of the halogenide with Iodogen for [123I] and [211At], and Chloramine-T (CAT) for [76Br] followed by halodestannylation of 5-trimethylstannyl-2-deoxyuridine (TMSUdR). The reaction takes 1 minute giving >90% yield for all three halogens.
A target system for the production of nucleophilic 110-min18F from isotopically enriched /18O/H2O is described. The process occurs via the nuclear reaction18O/p,n/18F, the available proton beam of 72 MeV must be degraded to the entrance energy of 15 MeV. This process is in regular use for the batch production of 0.8–1 Ci18F.
Authors:R. Weinreich, S. Qaim, H. Michael, and G. Stöcklin
The advantages of high energy cyclotrons as compared to small compact cyclotrons for the production of special radionuclides
are outlined. The routine production of123I (T=13.3 h) and28Mg (T=21.1 h) by means of high energy nuclear reactions at the Jülich Isochronous Cyclotron is described. The reaction127I(d,6n)123
123I at 78 to 64 MeV is used for the production of123I with thick target yields of 8 mCi/μAh and high radionuclidic purity. The practical experience in the application of this
process, which is well suited for the production of Na123I and for123Xe-exposure labelling techniques, is reported.28Mg is produced by the27Al(α, 3p)28Mg reaction at Eα=140 to 30 MeV with thick target yields of 40 μCi/μAh. The carrier-free28Mg is separated from the matrix activities by coprecipitation and anion exchange with chemical yields of 80%.
Authors:R. Weinreich, S. Bajo, J. Eikenberg, and F. Atchison
The formation of plutonium radionuclides (239+240Pu) from uranium was determined in dismounted shielding concrete from accelerator components. Plutonium and uranium fractions were separated by radioanalytical techniques and measured by -spectroscopy. The measurements are consistent with yield calculations based on transport and single particle codes. The yield of 239+240Pu did not exceed the two-fold exemption limit given in the Swiss Radiation Protection Law, thus the plutonium content in shielding concrete should not cause problem for the environment.