1. POSSIBILITIES OF PRODUCTION OF TECHNETIUM SHORT-LIVED RADIOACTIVE ISOTOPES O.D. Maslov, S.N. Dmitriev, A.V. Sabelnikov Flerov Laboratory of Nuclear Reactions JINR Dubna

2. Flerov Laboratory of Nuclear Reactions JINR Dubna

3. Flerov Laboratory of Nuclear Reactions JINR Dubna

4. Short-Lived Isotopes of Technetium IsotopeT 1/2 DecayUsing of the Tc isotopes 91m Tc 3.3 m IT, EC  + PET 91g Tc 3.14 m EC  + 92 Tc 4.23 m EC  + 93m Tc 43.5 m IT 93g Tc 2.7 h EC,  + 94m Tc 52 m EC  + PET imaging to bear on technetium pharmacology. The testing of radiopharmaceuticals labeled with 99m Tc. 95g Tc20 hEC Radiochemical studies 95m Tc61 d EC,  + The 95m Tc and 96 Tc tracers are applicable to numerous fields for medical, biological and environmental scientific studies 96 Tc4.3 dEC 96m Tc52 mEC 97m Tc91 d Tracers for environmental research 99m Tc6 h -- Nuclear medicine

5. Target and nuclear reaction for production of Tc isotopes Element -target ReactionTc 9293m9394m9495m9697m9899m Mo(p,n)+ ++++ + (p,2n) +++ + + (p,np) + ( ,2n) ++ + ( , xn) ++++ ( ,xnp) ++ (d,n) + (d,2n) ++ (n,  ) + ( ,n) + Nb ( ,n) + ( ,2n) ++ ( ,3n) ++ (d,2n) + ( 3 He,3n) + Ru ( ,n) ++ Rh(p, spal.) + U(n,f) +

6. Tc isotopes produced by irradiating a 0.1 mm Mo foil with an 11 MeV proton beam ReactionAbund. % Value (MeV) T 1/2 DecayY 53 min (mCi/  A) 92 Mo(p, n) 92 Tc14.8-8.84.4 min 92%  + 1.4 94 Mo(p, n) 94m Tc9.3-5.153 min 72%  - 1.7 94 Mo(p, n) 94 Tc9.3-5.0293 min89% EC 90 95 Mo(p, n) 95m Tc15.9-2.562d96% EC 0.64 95 Mo(p, n) 95 Tc15.9-2.420.1 h100% EC 130 96 Mo(p, n) 96 Tc16.7-3.74.3 d100% EC 60 100 Mo(p, 2n) 99m Tc9.6-7.76.0 h99% IT109 Abund.(%) natural isotopic abundance of molybdenum, Y 53 min, production yield for a 53 min irradiation.

7. Yield of technetium isotopes in Mo(p, n) reaction after end of irradiating enriched 94 Mo natural Mo Flerov Laboratory of Nuclear Reactions JINR Dubna

8. Tc production yields with  and 3 He beams ReactionQ (MeV) T 1/2 Yield(mCi/  A) 93 Nb( , 3n) 94m Tc -2553 min2.1 93 Nb( , 3n) 94 Tc -25293 min11 93 Nb( , 2n) 95 Tc -1520 h43 93 Nb( , n) 96 Tc +64.3 d11 93 Nb( 3 He, 2n) 94m Tc-453 min4.6 93 Nb( 3 He, 2n) 94 Tc-4293 min12 92 Mo( , 2n) 94 Ru -1852 min1.7 92 Mo( , 2n) 95 Ru -81.6 h2.2 nat Mo( , xn) 97 Ru -2.9 d8 nat Mo( , xnp) 94m Tc -53 min0.5 (direct) nat Mo( , xnp) 94 Tc -293 min2.2 nat Mo( , xnp) 95 Tc -20 h0.8 (direct) nat Mo( , xn) 101 Tc -14 min0.14 Thick target yields

9. Alpha irradiation (33 MeV) of the many stable isotopes of molybdenum leads to a considerable number of technetium and ruthenium products through the ( , xnp) and ( , xn) reactions, respectively. Thus the purity of isotope is determined the choice target, bombarding particles and their energy, time of irradiation and cooling and radiochemical operations for separation and concentration of final isotope.

10. Flerov Laboratory of Nuclear Reactions JINR Dubna

11. Flerov Laboratory of Nuclear Reactions JINR Dubna

12. Flerov Laboratory of Nuclear Reactions JINR Dubna

13. 6  10 -2 mCi ( 99 Mo) = 1 g ( 100 Mo)  25 MeV  -rays  1  A  1 h ( ,p) 99m Tc (T 1/2 = 6.02 h; IT (100%); E  = 140.5 keV(87.7%) Yield of 99 Mo: ( ,n)  - 9899100 99m 99mg (n,  ) (n,2n) Production of the 99 Mo/ 99m Tc generator Reaction T 1/2 E th, MeV  max, mb E m, MeV , MeV Ab. 100 Mo( , n) 99 Mo 66.2 h9.117016.07.39.63 100 Mo( , p) 99 Nb 15 s16.56720.44.7 100 Mo( , p) 99m Nb 2.6 m16.91622.04.5 100 Mo(n,2n) 99 Mo66.2 d8.3 98 Mo(n,  ) 99 Mo 66.2 d 137 th 24.1 Tc Mo Nb Flerov Laboratory of Nuclear Reactions JINR Dubna

16. Yield of 99 Mo Photonuclear reaction: 100 Mo( ,n) 99 Mo 2.2 kBq ( 99 Mo) = 1 mg ( 100 Mo) * 25 MeV  -rays * 1  A * 1 h 1550 mCi ( 99 Mo) = 1 g ( 100 Mo) * 25 MeV  -rays * 25  A * 100 h 21.5 Ci ( 99 Mo) = 1 g ( 100 Mo) * 25 MeV  -rays * 500  A * 50 h

17. Production of the 95m, g Tc Flerov Laboratory of Nuclear Reactions JINR Dubna

18. Yield of 95m, 95g Tc 0.2 mCi ( 95m Tc) = 1 g ( 96 Ru)  25 MeV  20  A  100 h 0.3 Ci ( 95g Tc) = 1 g ( 96 Ru)  25 MeV  20  A  100 h Flerov Laboratory of Nuclear Reactions JINR Dubna Photonuclear reaction: 96 Ru( , n) 95 Ru  95m, g Tc

19. nat Mo( , n) 99 Mo 30 EL, I=500  A Thin targ. 99 Mo 10 -2 9 100 Mo( , n) 99 Mo 22Microtron, th. t. 99 Mo, estimate: 2.7 10 -3 6,7 10 The MT-25 of FLNR 99m Tc T 1/2 = 6 h nat Mo 10g ( , n) 99 Mo  25 99 Mo 1.4 10 -3 12 100 Mo( , n) 99 Mo  39025 99 Mo 6 10 -2 12 95m Tc T 1/2 =60 d / 95 Тc T 1/2 =20 h nat Ru( , n) 95 Ru T 1/2 1.65h ( nat Ru) 6 10 -6 (Y=7.2 kBq)  95m Tc ( 96 Ru) 10 -4  95 Tc ( nat Ru) 1.6 10 -2 ( 96 Ru) 0.3 97m Tc T 1/2 =91 d nat Ru( , n) 97 Ru T 1/2 2.9d ( nat Ru) 4 10 -8 (Y=50 Bq)  97m,g Tc ( 98 Ru) 2.3 10 -6

20. Yields of the technetium short-lived isotopes in (p, xn), ( , xn), (d, xn), ( 3 He, xn) and ( , n) reactions Flerov Laboratory of Nuclear Reactions JINR Dubna

21. Summary 1. Proton induced reactions on Mo will result in better isotopic purity and high yield. 2. Production of pure radioisotopes using the highly enriched isotope targets and carefully selected energies of bombarding particles are superior. 3.The considerable cost of the separated target material dictates quantitative 94 Mo reclamation, a further constraint on the Mo/Tc separation technique. 4. 93 Nb( , 3n) 94m Tc and 93 Nb( 3 He, 2n) 94m Tc: Although the monoisotopic nature of niobium restricts the entrance channel, exit channels are dominated by multiple- neutron evaporation reactions leading to 94 Tc, 95 Tc and 96 Tc 5.The higher yields and some way more restricted exit channels make. 93 Nb( 4 He,xn) 93, 94 Tc reaction preferable to the alpha irradiation. 6.Deuteron induced production of 94m, 99m Tc and 99 Mo on Mo-isotopes is no real alternative. 7.Irradiating 1 g of 100 Мо (100%) with 25 МeV bremsstrahlung, I e = 25  А for 100 hours produces 550 mCi of 99 Mo, and beam current of 250 mA – 1.5Ci 99 Mo. In despite of rather low productivity of ( , n) reactions the linear electron accelerators and microtrons can compete with more expensive and complex in operation by the proton cyclotrons and to provide the needs of separate clinics and regions. 8.Irradiating of 1 g of 96 Ru (100%) with 25 МeV bremsstrahlung, I e = 25  А for 100 hours produces 0.2 mCi 95m Tc and 0.3 Ci 95 Tc.