B i l i m s e l M a k a l e l e r /
S c i e n t i f i c Ar t i c l e s
A L T E R N A T IV E G EN E R A T O R S OF THE 99mTc S. K hujaev
Institute o f Nuclear Physics, Uzbekistan Academy o f Science, Tashkent, Uzbekistan
Introduction99mTc is the most widely used radionuclide in nuclear medicine. 99mTc radionuclide is obtained from a generator, in which 99Mo servest as the parent radionuclide. In the generator 99mTc and 99Mo radionuclides are found in genetic balance and 99mTc radionuclide is chemically extracted from the system periodically.
Although there already exists many ways and variants o f manufacturing 99mTc generators, search for new variants o f the 99Mo ^ 99mTc generator systems continue. An example is the investigations carried out with the support o f the IAEA [1,2]. In these research works, generators based on elution o f polymolybdate gels have been developed and evaluated.
These generators will be serving as alternative technologies for production o f 99mTc radionuclide, which use 99Mo produced by non-fission means.
It is known that in Australia and China more than 30% o f 99mTc generators are gel-generators [2]. The works o f authors [3-5] are devoted to the problem o f searching new perspective materials as a column material that will serve as adsorbent.
The main purpose o f all the research on alternative technologies is the usage o f parent radionuclide 99Mo that is obtained from 98Mo(n, y)99Mo reaction instead o f as a fission product.
Our work examines the possibility o f reception o f generators 99Mo ^ 99mTc using non-fission 99Mo that is based on insoluble salts o f molybdate.
Experimental
In our experiments insoluble salts, barium, calcium molybdates and phosphorous molybdate o f cesium were used. Solubility o f the specified salts are presented below:
B a M o O 4 -4 .1 0 -8; Ca M o O 4 -4 ,7 .1 0 -9;
Css [P (MosOio)4]- 1,7.1ü-11.
Salts o f barium and calcium were obtained by adding 99Mo radionuclide into the chemical structure o f
2+ 2+ 99 2
the salts during their synthesis. Solutions containing Ba , Ca and MoO4 " ions are mixed and the following resoluble salts o f molybdate precipitate:
Ba2+ + 99MoO42- ^ Ba99M oO4 (1)
Ca2+ + 99MoO42- ^ Ca99M oO4 (2)
Phosphorous molybdate o f cesium was obtained by mixing solutions containing ions o f Cs+ and phosphorous molybdate (99Mo) :
3Cs+ + [P(99Mo3Oio)4]3- ^ Css[P(99MosOio)4] (3)
B i l i m s e l M a k a l e l e r /
S c i e n t i f i c Ar t i c l e s
The generators consisted o f glass columns with two layers: a lower layer o f AI2O3 (0,5g.), and an
upper layer o f insoluble salt o f 99Mo. W eight o f the salt varied from 1 to 2g. Pertechnetate (99mTc)
sodium was extracted with 0,9% solution o f NaCl at a speed o f 0,5 to 1,5 ml/min.
Results
99Mo is generally produced by direct (n,y) nuclear reaction o f irradiated natural Molybdenum or enriched 98Mo.
Output o f insoluble salts o f molybdate (99Mo) on its synthesis was more than 95% for all salts. This
means that the loss o f 99Mo in the process o f obtaining insoluble salts is minor.
Quantity o f yield o f 99mTc from salt generators on elution in 0,9% solution o f NaCl are presented in Table 1.
Table 1. Yield o f 99mTc from salt generators
Salt Yield of 99mTc, % Content of 98Mo,
%
Radiochemical purity, %BaMoO4 70,8 less than 1 0 -3 99,7
Ca MoO4 75,2 0 , 0 2 99,5
Cs3 [P (Mo3O!0)4] 77,6 less than 1 0 -4 99,8
N ot so high yield o f 99mTc radionuclide indicates that Technetium-99m is adsorbed in the molybdate salts. Table 1. Also shows radiochemical and radionuclide purity o f pertechnetate (99mTc). Result
obtained support the usability o f salt generators in practice.
References
1. Castro, R.D., Charoen, S., M arques, R., Miller, J., Narasimhan, D., Savishkin, I., Seifert, S., Sukonpradit, W ., Van So, L., Vera-Ruiz, H., W agner, G. Alternative technologies for 99mTc generators. Final Report o f a Co-Ordinated Research Programme 1990-1994. IAEA-TECDOC- 852. Vienna, 1995, p. 52.
2. Boyd, R.E. The Gel Generator Option. IAEA-TECDOC-1065. Vienna, 1999, p. 9.
3. Hasegawa, Y., Nishino, M., Ishikawa, K. A New Inorganic Adsorbent o f (n,gamma)99Mo for the Practical 99mTc Generator. W orkshop on the Utilization o f Research Reactors. Bondung (Indonesia) 6-13 Nov. 1997. Proc. 1998, p. 3-14.
4. Zaohawilai, S. The Preparation o f 99mTc from 98Mo-99mTc Generator Using Poly-Zirconium
Compound. W orkshop on the Utilization o f Research Reactors. Bondung (Indonesia) 6-13 Nov. 1997. Proc. 1998, p. 25-30.
5. Sombrito, E.Z., Bulos, A.D., Tangonan, M.C. Performance Tests on Column M aterials for 98Mo-
99mTc Generator. W orkshop on the Utilization o f Research Reactors. Bondung (Indonesia) 6-13 Nov. 1997. Proc. 1998, p. 34-40.
