Kenneth L. Scholz

Cyclotron production of rhodium-101m through its precursor palladium -101

The preparation of high-purity 101m Rh through its natural precursor, 101 Pd was investigated. The 103 Rh(p,xn) 101 Ag-> 101Pd; Pd (p,pxn) 101Pd reactions were studied. An anion exchange method was used to isolate the 101 Pd produced and to then isolate 101m Rh after ingrowth. Maximum yield of 101m Rh was 4 mCi/&μA-hr achieved when rhodium metal was irradiated with 37-MeV protons. Rhodium- 101/w was also incorporated in rhodium II butyrate, a compound used in chemotherapy.

Production of Thulium- 167 for medical use by irradiation of letetium, hafnium, tantalum and tungsten with 590-MeV protons

Abstract The feasibility of producing high-purity 167 Tm by spallation for use in nuclear medicine was investigated. Lutetium-oxide powder and hafnium, tantalum and tungsten foils were irradiated with 590-MeV protons. Cross section for the formation of 167 Tm and contaminating 168 Tm were determined; the best target material was tungsten with cross sections averaging 49 and 0.39 mbarns for 167 Tm and 168 Tm, respectively. The average amount of 168 Tm from the tungsten target was 0.09% of the 167 Tm activity and this equals the lowest contamination achieved with low-energy proton and 4 He-ion-induced reactions.

A gas-flow powder target for the cyclotron production of pure 123I

Abstract A gas-flow 122Te powder target is described for the production of 123I via the 122 Te ( 4 He , 3n) 123 Xe 123 I reaction. Iodine-123 yields in the range of 2–4 mCi/h have been obtained from 1–1·5 g 123Te (≈96 per cent) targets bombarded with 42-MeV alpha particles at beam currents of ∼50 muA. At typical bombardment conditions, the 124I contamination can be held to as low as 0·001 per cent. The 125I contamination which results from decay of 125Xe collected in the liquid nitrogen trap was 0·4 per cent. No other radioiodine contamination was detectable. Analysis of Ge(Li) spectra of high-purity 123I showed energies and relative intensities of 13 previously unreported gamma lines at 198·5, 330, 450·0, 697·5, 836·4, 876·9, 894, 908, 1035 and 1067 keV. The same target could also be used to produce 123I via the 122 Te ( 3 He , 2n) 123 Xe 123 I and 123 Te ( 3 He , 3n) 123 Xe 123 I reactions.

A kit for the production and fast isolation of medically useful fluorine-18

Abstract A simple kit-method for the reactor production of medically useful 18 F is described. The 18 F is collected from acid solution on hydrous zirconium oxide, eluted with dilute base, and prepared for injection. The chemical yield of the 30-min procedure is 80 per cent. About 4 mCi of 18 F per gram of 95 per cent enriched 6 Li 2 CO 3 can be delivered 3 hr (transportation and separation time) after the end of a 4-hr irradiation in a neutron flux of 1·5 × 10 13 cm −2 sec −1 . The tritium content of the final product is 2–3 per cent corrected to the end of the irradiation. Other radioactive impurities such as 24 Na and 42 K are less than 0·001 per cent. Repeated tests have shown the 18 F product to be sterile and non-pyrogenic.

52Fe production for medical use from 588‐MeV‐proton irradiation of Mn, Co, Ni, and Cu targets

The average cross sections for 52Fe production from the bombardment of 588‐MeV protons on manganese,cobalt,nickel, and copper targets were measured as 0.066±0.013, 0.152±0.012, 1.35±0.30, and 0.148±0.013 mb, respectively. A simple chemical procedure for the dissolution of the target in mineral acid and the extraction of 52Fe into di‐isopropyl ether is described. The long‐lived radiocontaminants in an 52Fe product from a single extraction of a nickel target irradiated for 0.5 h were 44Sc (0.02%), 44mSc (0.11%), 47Sc (0.01%), 48V (0.14%), 55Fe (3.3%), and 59Fe (0.16%).

Spallation production of 127Cs-129Cs mixtures for medical use

Abstract The feasibility of producing 127Cs-129Cs mixtures by spallation for use in nuclear medicine was investigated. It is possible to use this mixture since the energies of the principal gamma-ray emissions of both 6-h 127Cs and 32-h 129Cs are similar. Chemical compounds of barium, lanthanum, cerium, praseodymium and neodymium were irradiated with 590-MeV protons; and thin-target cross sections were determined for the formation of the desired 127Cs and 129Cs, and the unwanted contaminants 132Cs and 136Cs. Cross sections for the formation of 127Cs, 129Cs, 132Cs and 136Cs from praseodymium, which gave the purest 127Cs-129Cs from the five targets irradiated, were 49 ± 8, 58 ± 8, 0·23 ± 0·06 and 0·011 ± 0·008 mbarn, respectively. The total 132Cs-136Cs contamination 24 h after the end of a typical irradiation was 0·08 per cent of the 127Cs-129Cs activity. Ge(Li) spectra showed that the chemical procedure used quantitatively removed all non-cesium radioactive impurities.