2017 Mo-99 Topical Meeting Sep. 13, 2017 Montréal, QC, Canada Photonuclear production of Mo-99/Tc-99m using molybdenum trioxide and activated carbon J. Jang 1, * and M. Uesaka 1 K. Tatenuma 2 and A. Tsuguchi 2 S. Sekimoto 3 and T. Ohtsuki 3 1 University of Tokyo, Bunkyo, Tokyo, Japan 2 Kaken Inc., Mito, Ibaraki, Japan 3 Research Reactor Institute, Kyoto University, Sennan, Osaka, Japan
Contents 99 Mo production via MoO 3 ( γ , n ) 1. 99m Tc separation and purification using TcMM 2. 100 Mo recovery from spent Na 2 MoO 4 ( aq ) 3. 4. Electron linear accelerator design 5. Summary and current works
Photonuclear production of 99 Mo 99 Mo pr prod. 99 Tungsten (W) converter Molybdenum (Mo) target Why MoO 3 MoO 3 ( γ , n ) Electron linear 99m Tc sep sep. 99m γ 100 Mo( γ ,n) 99 Mo accelerator TcMM process (six steps) (linac) 100 Mo 99 Mo e - 100 Mo r 100 recovery γ Photon e - li linac desi sign n Photoneutron Summary Summa 100 Mo( 𝜹 , n ) 99 Mo • Nuclear reaction between photons ( 𝜹 ) and a 100 Mo nucleus • Threshold is ~8 MeV; electron linac can be used as the source of these high-energy photons (bremsstrahlung) • We irradiate MoO 3 pellets rather than metallic Mo disks – Why? 3
Merits of using MoO 3 over metallic Mo 99 Mo pr prod. 99 Why MoO 3 MoO 3 Metallic Mo [1] MoO 3 ( γ , n ) 99m Tc sep sep. 99m TcMM process (six steps) Spark plasma sintering Spark plasma sintering 100 100 Mo r recovery Molar mass ( g mol −1 ) 143.94 95.94 e - li linac desi sign Melting point ( K ) 1068.15 2895.15 Boiling point ( K ) 1428.15 4912.15 Summary Summa Mass density ( g cm −3 ) 4.69 10.28 • Simple dissolution, • High density in both Pros and hence powder and pellet • Easy 100 Mo recovery forms • Efficient target from spent Na 2 MoO 4 ( aq ) • Easy palletization cooling [1] K. Ishikawa et al. (2011), AESJ 2011 Annual Meeting, Fukui University, Fukui, Japan. 4
Pelletization: MoO 3 vs. Metallic Mo 99 Mo pr prod. 99 Why MoO 3 MoO 3 Metallic Mo [1] MoO 3 ( γ , n ) 99m Tc sep sep. 99m TcMM process (six steps) Spark plasma sintering Spark plasma sintering 100 100 Mo r recovery Powder mass density 4.69 10.28 𝜍 pow ( g cm −3 ) e - li linac desi sign 4.45 ( = 0.95 𝜍 pow ) 7.29 ( = 0.71 𝜍 pow ) Pellet theoretical Summary Summa density 𝜍 pel ( g cm −3 ) at 𝑈 𝑡 = 873.15 K at 𝑈 𝑡 = 1373.15 K sintering temperature MoO 3 is pelletized at lower 𝑈 𝑡 and hence shorter sintering time! [1] K. Ishikawa et al. (2011), AESJ 2011 Annual Meeting, Fukui University, Fukui, Japan. 5
MoO 3 irradiation using L-band e - linac 99 Mo pr prod. 99 L-band (1.3 GHz) electron linac [1] Why MoO 3 at KURRI [2] , Japan MoO 3 ( γ , n ) • Beam energy: 30 – 46 MeV 99m Tc sep sep. 99m • Average beam power: ~10 kW TcMM process • We have been irradiating [ nat Mo]MoO 3 (six steps) and [ enr Mo]MoO 3 pellets using this linac 100 Mo r 100 recovery (enriched in 100 Mo) e - li linac desi sign We will address experimental results conducted on Summary Summa Dec. 12 – 22, 2016; the irradiation conditions were Beam energy 35 MeV Average beam power 1.19 kW Beam-on time 10 min • [ nat Mo]MoO 3 ϕ 10 mm, 3 mm-thick, 1.06 g • pellets Three such pellets were irradiated Before & after irradiation [1] http://www.rri.kyoto-u.ac.jp/en/facilities/ela [2] KURRI stands for Kyoto University Research Reactor Institute. 6
Low specific activity (LSA) of ( γ,n ) 99 Mo 99 Mo pr prod. 99 2 mg Mo Why MoO 3 𝒚 = 𝟑 [1] × 𝒚 g Al 2 O 3 = 4 mg Mo MoO 3 ( γ , n ) g Al 2 O 3 99m Tc sep sep. 99m Mo adsorption Amount of alumina Amount of Mo cap. of alumina [2] per column per column TcMM process (six steps) A sp,F−Mo ≅ 1.85 × 10 5 GBq/g [1] 100 Mo r 100 recovery fission 4 mg Mo × 1.85 × 10 5 GBq e - li linac desi sign = 7.4 × 10 2 GBq = 20 Ci g Mo Summary Summa (Before calibrated to six-day Ci) A sp,γ−Mo ≅ 67.35 GBq/g (2,747 times lower) Monte Carlo simulation result photonuclear 𝒚 = 𝟔, 𝟓𝟘𝟓 To obtain the same 99 Mo activity per 99m Tc generator using photonuclear-produced 99 Mo, ~5.5 kg of alumina is required → New 99m Tc generator compatible with LSA 99 Mo is needed [1] IAEA (2013), Non-HEU Production Technologies for Molybdenum-99 and Technetium-99m . [2] A. Dash, F. F. R. Knapp, Jr., and M. R. A. Pillai (2013), 99 Mo/ 99m Tc separation: An assessment of technology options. Nucl. Med. Biol. 40(2): 167 – 176. 7
Technetium Master Milker (TcMM) Technetium Master Milker (TcMM) 99 Mo pr prod. 99 99 Mo pr prod. 99 Why MoO 3 TcMM MoO 3 ( γ,n ) Why MoO 3 • Developed by Kaken Inc., Mito, Japan MoO 3 ( γ , n ) 99m Tc sep sep. • 99m Can be used with both LSA- and HSA- 99 Mo 99m Tc sep 99m sep. TcMM process • Uses two columns of: (six steps) MoO 3 dissolution • Activated carbon (AC), which adsorbs Tc(VII) 99m Tc adsorption to AC 100 Mo r 100 recovery oxoanions but not Mo(VI) ones (opposite of alumina) 99 Mo removal from AC 99m Tc elution from AC • Activated alumina (AA), which adsorbs Mo(VI) e - li linac desi sign 99m Tc purification by AA oxoanions in the eluate of Tc(VII) oxoanions 99m Tc elution from AA Summa Summary • Exhibits 99m Tc elution efficiencies of ≥ 90% [2] 100 Mo r recovery 100 • Consists of six steps; these will be explained step by step e - li linac desi sign Related articles Summary Summa [1] S. Sekimoto et al. (2017), Separation and purification of 99m Tc from 99 Mo produced by electron linear accelerator, J. Radioanal. Nucl. Chem. 311(2): 1361 – 1366. [2] K. Tatenuma et al. (2016), Generator of Highly Concentrated Pure 99m Tc from Low Specific Activity 99 Mo Produced by Reactor and/or Electron Linear Accelerator, 2016 Mo-99 Topical Meeting, St. Louis, Missouri. [3] K. Tatenuma et al. (2016), Method of recovering enriched radioactive technetium and system therefor, US Patent 9,236,153. [4] K. Tatenuma et al. (2014), A mass-production process of a highly pure medical use 99mTc from natural isotopic Mo(n, γ)99 Mo without using uranium, RADIOISOTOPES 63(11): 501 – 513. 8 8
① Dissolution of irradiated MoO 3 pellets 99 Mo pr prod. 99 Na 2 MoO 4 𝑏𝑟 Why MoO 3 MoO 3 ( γ , n ) 99m 99m Tc sep sep. MoO 3 dissolution 99m Tc adsorption to AC 99 Mo removal from AC 99m Tc elution from AC 99m Tc purification by AA 99m Tc elution from AA Irradiated MoO 3 pellets 100 Mo r recovery 100 6-M NaOH 𝑏𝑟 Magnetic stirrer e - li linac desi sign Summa Summary • MoO 3 pellets were dissolved in a 6-M NaOH 𝑏𝑟 solution, simply by MoO 3 𝑡 + 2NaOH 𝑏𝑟 → H 2 O 𝑚 + Na 2 MoO 4 𝑏𝑟 2Na + 𝑏𝑟 + MoO 4 2− 𝑏𝑟 • Diluted to 200 mL, the Na 2 MoO 4 𝑏𝑟 solution had an average pH of 8.12 out of three such solutions 9
② 99m Tc adsorption to activated carbon 99 Mo pr prod. 99 Activated carbon (AC) Why MoO 3 • Has a high surface-to-volume ratio MoO 3 ( γ , n ) • Used in purifying air and water, etc. Adsorbs TcO 4 − 𝑏𝑟 ions but not 99m Tc sep 99m sep. • MoO 4 2− 𝑏𝑟 ones MoO 3 dissolution 99m Tc adsorption to AC 99 Mo removal from AC Why? 99m Tc elution from AC 99m Tc purification by AA The principle of selective adsorption of TcO 4 − 𝑏𝑟 to AC 99m Tc elution from AA remains unclear; we are investing 100 Mo r recovery 100 and planning experiments. e - li linac desi sign 2.0-g AC column Summary Summa • The 200-mL Na 2 MoO 4 𝑏𝑟 solution, containing MoO 4 2− 𝑏𝑟 constantly decaying to TcO 4 − 𝑏𝑟 , was poured into the AC column. TcO 4 − 𝑏𝑟 ions, where Tc consists of 99m Tc and a small amount of • 99g Tc, were then tightly bound to the AC, while only marginal amounts of the MoO 4 2− 𝑏𝑟 ions, where Mo consists of various Mo isotopes, were captured by the AC. 10
③ 99 Mo removal from activated carbon H 2 O 𝑚 & NaOH 𝑏𝑟 99 Mo pr prod. 99 50 mL 15 mL Why MoO 3 Weakly 9 mL MoO 3 ( γ , n ) bound MoO 4 2− 𝑏𝑟 Strongly bound TcO 4 − 𝑏𝑟 99m Tc sep 99m sep. 99 Mo MoO 3 dissolution 99m Tc 99m Tc 99m Tc adsorption to AC 99 Mo removal from AC 98 Mo 99m Tc elution from AC AC AC 42 99m Tc purification by AA 99m Tc elution from AA 99m Tc 99m Tc 100 Mo 100 Mo r recovery 100 e - li MoO 4 2− 𝑏𝑟 and TcO 4 − 𝑏𝑟 above linac desi sign 2.0-g AC column are parts of their respective Na salts Summary Summa Reused Na 2 MoO 4 𝑏𝑟 The minute amounts of MoO 4 2− 𝑏𝑟 ions were flushed into the • poured Na 2 MoO 4 𝑏𝑟 solution with H 2 O 𝑚 and NaOH 𝑏𝑟 . 99 Mo MoO 4 𝑏𝑟 solution was then allowed to decay to • The Na 2 Na 99m Tc TcO 4 𝑏𝑟 and poured again into the AC column. 11
③ 99 Mo removal from activated carbon 99 Mo pr prod. 99 • This “AC -filtere d” Na 2 MoO 4 𝑏𝑟 solution in which 99 Mo Why MoO 3 decays to 99m Tc is reused until the 99 Mo loses most of its MoO 3 ( γ , n ) activity 99m 99m Tc sep sep. MoO 3 dissolution 99m Tc adsorption to AC 99 Mo removal from AC Strongly 99m Tc elution from AC bound 99m Tc purification by AA Weakly 99m Tc elution from AA bound 99m Tc 100 Mo r recovery 100 100 Mo AC Weakly e - li linac desi sign bound 99m Tc 99 Mo Summary Summa 99m Tc 12
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