medicine represents more than 20 Billion $ in medical fees 99m Tc are conducted in the world. This not only is

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1 Radio Isotopes (RI) in Nuclear Medicine Nearly 80% of the RI used in nuclear medicine i are produced in nuclear reactors Among these reactor produced RI, the Technetium 99m (6 hrs), a decay product of Molybdenum 99 (66 hours) is the most commonly used RI in nuclear medicine Every year, 36 million medical procedures based on 99m Tc are conducted in the world. This not only is critical for the timely diagnostic of patients, but also represents more than 20 Billion $ in medical fees

2 99m Tc LOW SUPPLY PROBLEM! l hi d f h ld l Almost two thirds of the world s supply comes from two reactors: the Chalk River reactor in Ontario, Canada, and the Petten reactor of the Netherlands. However the Chalk River reactor has been shut down for maintenance since August 2009, with an expected reopening in April 2010, and the Petter reactor has a 6 month scheduled maintenance shutdown beginning on Friday, February 19, 2010.

3 99 Mo/ 99 Tc decay scheme

4 Thermal neutron capture cross section for the 98 Mo(n,γ) 99 Mo reaction. Nuclear Instruments and Methods in Physics Research B 267 (2009) Year Authors σ 0 (barn) % Difference Monitor 2008 This work ± Au 2006 ENDF/B-VII.0 M.B. Chadwick et al., JENDL JEF Babich and Anufriev 0.14 ± De Corte and Simonits ± Au 1987 Gryntakis et al. 013± Mughabghab 0.13 ±

5 99 Mo 99m Tc production (I) 99 Mo can be produced dby neutron capture on natural Mo ( 98 Mo is 24%). The process is simple and inexpensive, but yields a very low specific activity High specific activity 99 Mo ( Ci/g)can be obtained by 235 U fission. 6% of the 235 U fission events produce a 99 Mo nucleus as a fission product. In today s production, aluminum targets containing 4 gm of HEU are irradiated for a week in high flux research reactors. After irradiation, the highly radioactive target is allowed to decay for one day, then is sent to the processing facility.

6 DATA for 99 Mo Production Evaluation Process : 235 U fission n+ 98 Mo abund. : 20 %(LEU) 24% of nat Mo Probability: σ f ~0.6 kb Branch. R. : 6 % ~0.8 σ th =0.13 B Den.(g/cm 3 ): RRR : / =

7 99 Mo 99m Tc production (II) The irradiated dheu targets (40, Ci) are transported to the 99 Mo processing facility (Fleurus, Petten, Chalk River ) The targets are dissolved, and the selected fission products are chemically separated. Each target gives ~ 800 Ci of 99 Mo, or 135 Ci post calibrated 6 days The world weekly production is 8,000 to 10, Ci, p.c. 6 days. USA and Western Europe use most of this. So each week, about 60 targets are irradiated worldwide The purified 99 Mo is sent in bulk form to the producers of Generators

8 99 Mo 99m Tc production (III) For the distribution ib i to the final customer, the Mo99 solution is fixed on a small ion exchange alumina column The Mo99 (66 hours) decays continuously into Tc99m. Because of its different chemical properties, the Tc99m is not stably fixed on the alumina column When needed, the user washes the Tc99m out of the ion exchange column with a sterile saline solution The Tc99m is used to label a molecule which will target the body site to be studied

9 99 Mo 99m Tc production (IV) 99m The cost of a 99m Tc patient dose to the hospital is generally less than 15 (but this cost is rising). In this price, the cost of the neutron irradiation of the target is today less than 1 Reactor produced isotopes, such as Tc99m are therefore much less expensive than cyclotron-produced RI (150 to 300 per patient dose)

10 Gamma Ray Scintigraphy by 99m Tc : In vivo Bio Distribution Study (INFN Roma1, Roma3, Bologna, Legnaro/PD) A C B D Biodistribution studies of paclitaxel-ha. In vivo distribution of 99m Tc-labeled bioconjugate was investigated in anesthetized mice (A) using a high-spatial resolution YAP gamma camera. Images presented were taken 2 hours after administration and refer to mice inoculated intravenously (B), intraperitoneally (C) or after bladder instillation (D).

11 The Scintirad high resolution YAP Camera with manipulator (INFN Roma1, Roma3, Bologna, Legnaro/PD) The high spatial resolution (1.6 mm FWHM for 141 kev photons) YAP Camera has been employed to measure in vivo biodistributions of gamma emitting radiopharmaceuticals, as well as to localize radioactive hot spots (captation by cancer aggregate cells). Precision needle biopsy can be achieved by the computer controlled movable arm.

12 ARRONAX : Accélérateur pour la Recherche en Radiochimie et Oncologie à Nantes Atlantique Research in Nuclear Medicine : diagnostic imaging (PET), radiotherapy. Radiolysis, radiation damage Nuclear Waste Analysis

13 ARRONAX summary Financing Global Budget : 33. M p, d, α beams E p max=70 MeV, Imax=0.75 ma Radioisotope research/production : 67 Cu, 47 Sc, 177 Lu, 82 Rb, 211 At

14 Accelerator based Methods ADONIS A.D.O.N.I.S. Project, Belgium (Accelerator Driven i Operated New Irradiation System) Y. Jongen,IBA V1 (1995): 150 MV MeV x ma = 225 kw of proton beam Converted in a tantalum target to 7.5 E15 neutrons/second These neutrons produce 700 kw of fission power in standard dheu isotope production targets t surrounding the neutron target Weekly production of 5000 Ci of Mo99 (postcalibrated 6 days EOI)

15 ADONIS A 150 MV15 MeV, 1.5 ma cyclotron, using H acceleration and extraction by stripping, as the C30 and ARRONAX A beam line bi bringing i the extracted t dbeam vertically up to a subcritical assembly (consisting of secondary 235 U targets) located in another vault A Tantalum target converting the proton beam into neutrons by spallation An assembly of standard isotope production HEU targets arranged in water around the neutron source

16 ADONIS SCHEMATIC REPRESENTATION Cyclotron outside diameter: 6.42 m Cyclotron magnet vertical size: 2.16 m Cyclotron magnet weight: 405 Tons Ampere turn in main coils: Aturn Total power in main coils: 92 kw

17 Ta SPALLATION TARGET The Thick Target Yield increases rapidly with beam energy Emitted neutrons are mostly evaporation neutrons, with E < 20 MeV Evaporated neutrons are emitted nearly isotropically by the target

18 IBA Sub Critical Assembly Design (1) Be reflector HEU targets Be moderation rings Ta target

19 IBA Sub Critical Assembly Design (2) Be moderation rings Targets immersed in D2O Be Reflector Ta target 2 rows of HEU targets (L=40cm)

20 Sub Critical Structure Details Conical Tantalum spallation target. Design based on cylindrical targets as used today. Beryllium moderation rings between target layers. HEU targets (4g) immersed into D2O. Be reflector (20 cm thick). Targets disposed on 4 cylindrical layers, each layerbeingmadeof2 rows oftargets Total of 150 targets

21 Effective Critical Parameter Evaluation DESIGN LIMIT

22 ADONIS V2 Project In ADONIS V1, the total production meets the specifications, but the activity per target is too low. To get the required production, more targets needs to be fabricated and processed, increasing the production costs to the point where the concept in not competitive anymore This is because in ADONIS V1, the neutron flux (~10 10 neutrons/cm²/sec) is lower than in the current research reactors To increase the neutron flux without increasing the K, the only solution is to increase the primary neutron source by increasing the energy Increasing the energy to 350 MeV, with 1.5 ma of proton current allows to reach the required activity per target. But the beam power becomes 525 kw, and the fission power 5 MW The required cyclotron is a 350 MeV, 1.5 ma superconducting cyclotron, similar to the C400 designed by IBA for carbon beam therapy, using H2+ acceleration and extraction by stripping

23 The 350 MeV H2+ superconducting cyclotron

24 Superconducting cyclotron parameters Accelerated dbeam: 750 μaa of H2+ up to 700 MeV Extraction by stripping of the H2+ into protons K bending 1600 R extr. 187 cm, Hill field 4.5 T, Valley field 2.45 T, weight 650 T Design similar to IBA C400, with the following modifications: Enlarged magnet gap at large radii Higher g power, 350 kw RF FPA for each cavity Larger vacuum pumps Protection and cooling of the central region

25 New ADONIS Budget While the initial iti ADONIS concept was to use 225 kw of proton beam to induce 700 kw of fission power, in the revised ADONIS concept 525 kw of proton beam is employed to induce 5 MW of fission power. The costs have escalated more or less proportionally The nuclear island has been budgeted by SCK at 50 MEuros The new cyclotron, with beam line and primary target has been estimated by IBA to 38 Meuros (this does not include the cyclotron building) With the cyclotron building, the initial working capital and cost offinancing, the amount to finance exceeds now 100 MEuros

26 Alternative Solution to 99 Mo Production? A possible answer is direct fission of natural uranium or LEU by proton beams. The cross section of proton induced fission of U238 and U235 is quite high (1.5 barn) and quite constant from 20 MeV to 1 GeV

27 Post ADONIS : Proton induced Fission In addition to thermal neutrons, Uranium has significant fission cross sections for Protons above 20 MeV σ(p,f) ~ 1.5 barn Neutrons above 10 MeV σ (nf) (n,f) ~ barn For these particles, 235U and 238U exhibit very similar cross sections : ENHANCED FUEL COMBUSTION EFFICIENCY!

28 HIGHER ENERGY n,p,d induced npd FISSION 238 U Fission Cross Section Sigma (B Barn) neutron proton deuteron Energy (MeV)

29 LEU Target Assembly Target made of mm thick metallic Uranium foils. U foil radius = 3 cm or 5 cm. U foils separated by 1 mm thick water channels for cooling. Consider only Lowly Enriched hd Uranium (LEU) with 235U fraction below 20%. Proton beam = 200 MV MeV or 350 MV MeV with 1 ma. Beam radius = 2.8 cm For Ebeam = 200 MeV, assembly limited to 80 foils. For Ebeam = 350 MeV, assembly contains 142 foils.

30 Total 99 Mo activity generated by neutron fissions with 235 U content at 200 MeV and 350 MeV.

31 Proton induced fission of LEU 80 (200 MV) MeV) or 142 (350 MV) MeV) foil iltargets t made of mm plates of LEU, irradiated 3 days Total production is 2100 Ci/week (PC 7 days) y) at 200 MeV, 1.5 ma, or 7100 Ci/week (PC 7 days) at 350 MeV, 1.5 ma using 20% enriched LEU The Keff of such a target assembly is less than This is not anymore a subcritical reactor, it is a uranium target Activity would be 50% of this using 2% enriched LEU, and 25% of this using natural, un enriched Uranium The total investment required would be around 35 M for the 200 MeV unit, and around 50 M for the 350 MeV This is probably, for the moment, the most cost effective alternative to reactors.