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Production of99Mo for Nuclear Medicine by100Mo(n,2n)99Mo

“…4) One also has to be aware of the amount of time required to obtain 99 Mo from the production place; when it takes one week, the 99 Mo activity becomes one-sixth of the initial value. The specific activity of 99 Mo using HEU is quite high, more than 370 TBq/(g of 99 Mo), 7,8) since the cross section of 235 U(n,fission) at the thermal neutron energy is quite high, 585.1 b, the production fraction of 99 Mo by fission is 6.1%, and the thermal neutron flux is high, a factor times 10 14 n/ (cm 2 s). A high specific activity of 99 Mo is quite important to obtain a carrier-free 99m Tc, as discussed below.…”

“…4) In line with RERTR, and in ensuring a constant and reliable supply of 99 Mo, alternative routes to produce 99 Mo were studied. First, the production of 99 Mo by neutron activation of enriched 98 Mo targets has been demonstrated to be an attractive alternative, 7) although the specific activity of 99 Mo is low because of the small neutron capture cross section at the thermal neutron energy, 0.14 b. 10) Here, it is worth mentioning that since a method of recovering 99 Mo of thus obtained low to medium specific activity 7 -15 GBq/g, is available using such as a molybdenum-zirconium gel, 11) a new adsorbent named PZC (Poly Zirconium Compound), 12) and a tiny column of a strong base anion-exchanger (Dowex Tc due to their low cross sections of 130 mb at 30 < E p < 50 MeV, which covers the region of the maximum of the excitation function, and of lower than 0.2 mb at 6 < E p < 65 MeV, respectively.…”

Production Techniques of Fission Molybdenum-99

“…They are due to the fact that the low adsorptive capacity of alumina, the most commonly used generator bed material, requires the use of a large bed when low specific activity Mo-99 is employed, conversely with nearly carrier-free fission Mo-99 the bed size may be minimized ( ). An elution profile versus alumina bed weight which demonstrates the fact that solutions of Tc-99m with high specific activity can be obtained only from generators with a small bed volume has been reported by BOYD [1]. Unless new generator types can be developed this restriction will exist.…”

Technetium Generators: Status and Prospects

“…The MEK generator has been scaled down to suit the needs of a hospital department [5] and scaled up to meet the demands of a national supply service [6].…”