AU2002310305B2 - Process for the recovery of a radioisotope from an irradiated target - Google Patents
Process for the recovery of a radioisotope from an irradiated target Download PDFInfo
- Publication number
- AU2002310305B2 AU2002310305B2 AU2002310305A AU2002310305A AU2002310305B2 AU 2002310305 B2 AU2002310305 B2 AU 2002310305B2 AU 2002310305 A AU2002310305 A AU 2002310305A AU 2002310305 A AU2002310305 A AU 2002310305A AU 2002310305 B2 AU2002310305 B2 AU 2002310305B2
- Authority
- AU
- Australia
- Prior art keywords
- target
- dissolution medium
- radioisotope
- sonication
- irradiated
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Ceased
Links
- 238000000034 method Methods 0.000 title claims description 41
- 230000008569 process Effects 0.000 title claims description 29
- 238000011084 recovery Methods 0.000 title description 3
- 239000012738 dissolution medium Substances 0.000 claims description 43
- 238000000527 sonication Methods 0.000 claims description 38
- 239000000463 material Substances 0.000 claims description 37
- 239000010949 copper Substances 0.000 claims description 26
- 229910052709 silver Inorganic materials 0.000 claims description 26
- 239000004332 silver Substances 0.000 claims description 26
- 239000011343 solid material Substances 0.000 claims description 23
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 19
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 17
- 229910017604 nitric acid Inorganic materials 0.000 claims description 17
- 238000000926 separation method Methods 0.000 claims description 16
- 238000000746 purification Methods 0.000 claims description 13
- 238000004519 manufacturing process Methods 0.000 claims description 12
- 239000000523 sample Substances 0.000 claims description 12
- 239000011701 zinc Substances 0.000 claims description 10
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims description 8
- 239000002253 acid Substances 0.000 claims description 8
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 8
- BKVIYDNLLOSFOA-UHFFFAOYSA-N thallium Chemical compound [Tl] BKVIYDNLLOSFOA-UHFFFAOYSA-N 0.000 claims description 8
- 238000002360 preparation method Methods 0.000 claims description 5
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 4
- 239000011787 zinc oxide Substances 0.000 claims description 4
- 229910052759 nickel Inorganic materials 0.000 claims description 3
- 239000007800 oxidant agent Substances 0.000 claims description 3
- 229910052703 rhodium Inorganic materials 0.000 claims description 3
- 239000010948 rhodium Substances 0.000 claims description 3
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 claims description 3
- 229910052725 zinc Inorganic materials 0.000 claims description 3
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims description 2
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 claims description 2
- AJNVQOSZGJRYEI-UHFFFAOYSA-N digallium;oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Ga+3].[Ga+3] AJNVQOSZGJRYEI-UHFFFAOYSA-N 0.000 claims description 2
- 229910001195 gallium oxide Inorganic materials 0.000 claims description 2
- 229910052750 molybdenum Inorganic materials 0.000 claims description 2
- 239000011733 molybdenum Substances 0.000 claims description 2
- CXKCTMHTOKXKQT-UHFFFAOYSA-N cadmium oxide Inorganic materials [Cd]=O CXKCTMHTOKXKQT-UHFFFAOYSA-N 0.000 claims 1
- 229910000431 copper oxide Inorganic materials 0.000 claims 1
- 229910003438 thallium oxide Inorganic materials 0.000 claims 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 26
- 238000004090 dissolution Methods 0.000 description 21
- 229910052802 copper Inorganic materials 0.000 description 19
- 239000013077 target material Substances 0.000 description 19
- 239000000047 product Substances 0.000 description 16
- 238000012545 processing Methods 0.000 description 15
- 239000000243 solution Substances 0.000 description 10
- 229910052716 thallium Inorganic materials 0.000 description 9
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 8
- 230000008901 benefit Effects 0.000 description 7
- 230000002285 radioactive effect Effects 0.000 description 7
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 6
- 229910052737 gold Inorganic materials 0.000 description 6
- 239000010931 gold Substances 0.000 description 6
- 239000002245 particle Substances 0.000 description 6
- 239000000126 substance Substances 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 238000007654 immersion Methods 0.000 description 4
- 239000012535 impurity Substances 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 238000000638 solvent extraction Methods 0.000 description 4
- 150000007513 acids Chemical class 0.000 description 3
- 238000001704 evaporation Methods 0.000 description 3
- 230000008020 evaporation Effects 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- 230000005258 radioactive decay Effects 0.000 description 3
- 239000012217 radiopharmaceutical Substances 0.000 description 3
- 229940121896 radiopharmaceutical Drugs 0.000 description 3
- 230000002799 radiopharmaceutical effect Effects 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- BMYNFMYTOJXKLE-UHFFFAOYSA-N 3-azaniumyl-2-hydroxypropanoate Chemical compound NCC(O)C(O)=O BMYNFMYTOJXKLE-UHFFFAOYSA-N 0.000 description 2
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- 239000004411 aluminium Substances 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 238000012993 chemical processing Methods 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000009713 electroplating Methods 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- 230000006870 function Effects 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 238000004255 ion exchange chromatography Methods 0.000 description 2
- 238000002955 isolation Methods 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- IATRAKWUXMZMIY-UHFFFAOYSA-N strontium oxide Chemical compound [O-2].[Sr+2] IATRAKWUXMZMIY-UHFFFAOYSA-N 0.000 description 2
- -1 thallium nitrates Chemical class 0.000 description 2
- ZAFNJMIOTHYJRJ-UHFFFAOYSA-N Diisopropyl ether Chemical compound CC(C)OC(C)C ZAFNJMIOTHYJRJ-UHFFFAOYSA-N 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- QZPSXPBJTPJTSZ-UHFFFAOYSA-N aqua regia Chemical compound Cl.O[N+]([O-])=O QZPSXPBJTPJTSZ-UHFFFAOYSA-N 0.000 description 1
- 239000011260 aqueous acid Substances 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 229910052793 cadmium Inorganic materials 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910001385 heavy metal Inorganic materials 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 239000002609 medium Substances 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 230000002107 myocardial effect Effects 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 239000010970 precious metal Substances 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 238000007430 reference method Methods 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21G—CONVERSION OF CHEMICAL ELEMENTS; RADIOACTIVE SOURCES
- G21G1/00—Arrangements for converting chemical elements by electromagnetic radiation, corpuscular radiation or particle bombardment, e.g. producing radioactive isotopes
- G21G1/04—Arrangements for converting chemical elements by electromagnetic radiation, corpuscular radiation or particle bombardment, e.g. producing radioactive isotopes outside nuclear reactors or particle accelerators
- G21G1/10—Arrangements for converting chemical elements by electromagnetic radiation, corpuscular radiation or particle bombardment, e.g. producing radioactive isotopes outside nuclear reactors or particle accelerators by bombardment with electrically charged particles
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21G—CONVERSION OF CHEMICAL ELEMENTS; RADIOACTIVE SOURCES
- G21G4/00—Radioactive sources
- G21G4/04—Radioactive sources other than neutron sources
- G21G4/06—Radioactive sources other than neutron sources characterised by constructional features
- G21G4/08—Radioactive sources other than neutron sources characterised by constructional features specially adapted for medical application
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- High Energy & Nuclear Physics (AREA)
- Particle Accelerators (AREA)
- Radiation-Therapy Devices (AREA)
- Medicines That Contain Protein Lipid Enzymes And Other Medicines (AREA)
- Saccharide Compounds (AREA)
Description
WO 02/099816 PCT/US02/17678 Target Process Field of the Invention.
The present invention relates to an improved process for the recovery of a radioisotope from an irradiated target, such as a target from a cyclotron. The improvement comprises sonication of the target dissolution medium.
Background to the Invention.
It is known to prepare radioisotopes by bombardment of a non-radioactive target with particles, especially protons in a cyclotron, to convert a small percentage of the irradiated target surface into one or more radioisotopes. The radioisotope is then separated from the target by either: complete dissolution of the target plus radioisotope, (ii) partial dissolution of the target plus radioisotope, such that only the target surface containing the radioisotope is removed, leaving the target ready for further irradiation and purification cycles.
In both cases, the dissolution medium is subjected to further purification steps involving one or more selective separation techniques such as ion exchange chromatography, solvent extraction or precipitation. Method (ii) may employ controlled conditions such as limited concentrations or amounts of chemicals, or solvents in which only the target surface has significant solubility. Method (ii) is preferred where the target is relatively precious, eg. an artificially enriched level of a particular isotope to improve the yield of the desired radioisotope product, or the target comprises a precious metal. Method (ii) also has the advantage that there are lower levels of the non-radioactive target material present in solution. This makes the subsequent separation and purification of the radioisotope more straightforward. This is particularly useful when the radioisotope is to be used for medical applications involving administration to the human body (ie. a radiopharmaceutical), where removal of the potentially toxic levels of the non-radioactive target material (typically a heavy metal) is highly desirable.
US 4487738 discloses that carrier-free 6 7 Cu can be produced by proton spallation of a zinc oxide target with subsequent chemical separation and purification. The zinc oxide WO 02/099816 PCT/US02/17678 target is irradiated with protons having an energy of 800 MeV, and the irradiated target dissolved in concentrated acid. The 67 Cu is then separated by a series of ion exchange chromatography and precipitation procedures.
US 3993538 discloses that 201 T1 suitable for use as a myocardial imaging radiopharmaceutical can be prepared by bombardment of a thallium target with 20-30 MeV protons via the reaction 203 T1 (p,3n) 201 Pb. The 2 01 Pb radioisotope formed has a halflife of 9.4 hours, and decays to the desired 201 T1. After irradiation, the target is completely dissolved in concentrated nitric acid forming soluble lead and thallium nitrates.
Evaporation and further chemical purification steps gave the desired 201T product.
Use of target materials comprising two or more metals is known. Thus, US 4297166 discloses a thallium target for the production of the radioisotope 201 T1, in which the 23Tl target material is electroplated onto an electroconductive support such as copper or silver. The electroconductive support has two advantages. First, it can be used to provide efficient cooling of the thallium layer (via a circulating fluid such as water or gas).
Second, it can facilitate target processing, since only the thallium target layer and radioisotope formed is dissolved during processing. This makes the purification of the 2 01 T radioisotope more straightforward, since the processed target solution does not contain substantial amounts of the non-radioactive electroconductive support (eg. copper).
After chemical processing, the target electroconductive support can then simply be reused by electroplating with more thallium, and subsequent proton bombardment.
JP 04-326096 A (1992) discloses a cyclotron target which comprises silver plated onto a copper support. The desired target material 68 Zn) is plated onto the silver, and then irradiated with a proton beam. The silver layer means that no copper is present in the acid processing solutions, ie. the recovery and purification of the desired 68 Zn radioisotope is simplified.
US 6011825 discloses a cyclotron method for the production of radioisotopes, especially 6Cu. The 64Cu is produced by proton bombardment of a target which comprises 6Ni deposited onto a gold substrate. The irradiated 64Ni together with the 64CU product are dissolved off the gold disk in 6.0 M hydrochloric acid at 90 °C.
ID
0 Prior art chemistry used to process targets therefore typically employs concentrated solutions of mineral acids (eg. hydrochloric acid), or powerful oxidising d agents such as hydrogen peroxide. Acids which are also powerful oxidising agents, such as concentrated nitric acid may also be used. Heating is often also applied. Such forcing C1 5 conditions are understandable given that the target material to be dissolved may be a relatively unreactive metal such as rhodium. The difficulty of achieving the required dissolution of the target may also mean that extended contact times are required. For radioisotopes, all such target processing time is time during which radioactive decay of Cthe desired product is occurring, ie. product is being lost. The shorter the half-life of the radioisotope product, the bigger the potential problem this represents.
An additional problem with the use of such prior art forcing conditions is that careful handling of the radioactive process solution is required due to the chemical hazard as well as the radioactive hazard. In addition, when it is intended that only the surface of the irradiated target should be dissolved, such conditions increase the likelihood of dissolution of other elements of the target e.g. the electroconductive support. It is also the case that the process solutions consequently require more chemical processing, eg. to neutralise the strong acid, before proceeding further with the isolation and purification of the radioisotope.
There is therefore a need for an improved method of processing such radioisotope targets under milder conditions.
The Present Invention In a first aspect, the present invention provides a process for the production of a preparation containing a radioisotope from an irradiated target comprising: providing an irradiated target having a support material comprising silver; and a surface solid material comprising said radioisotope; wherein the surface solid material is disposed on said support material; (ii) treating the irradiated target with a dissolution medium; N]\Melbourne\Cases\Patent\51000-51999\P51497.AU\Specis\P51497.AU Specification 2006-12-18.doc 21/12/06 3
IO
c (iii) applying sonication to the dissolution medium whilst it is in contact with Sthe surface solid material of said irradiated target so that a portion of the radioisotope in the surface solid material dissolves in the dissolution material; (iv) isolating the dissolution medium containing the radioisotope; subjecting the dissolution medium to purification, thereby producing a Spreparation containing the radioisotope; and C (vi) optionally repeating steps (ii) to wherein the applying step is carried out under milder conditions CN compared to other conditions without sonication.
The target of the present invention suitably comprises a 'surface solid material' which, when irradiated with charged particles reacts to give one or more radioisotopes.
The surface solid material is thus that part of the irradiated target which reacts during the irradiation to give the desired radioisotope product. The charged particles are suitably derived from an accelerator, preferably a cyclotron. The charged particles may be protons, deuterons, alpha, 3He or electrons, and are preferably protons. Suitable surface solid materials include metals such as thallium, cadmium, rhodium, molybdenum or zinc, or metal oxides such as zinc oxide, strontium oxide or gallium oxide, plus such materials containing an artificially enriched level of a particular isotope. Preferred surface solid materials are those which are suitable for plating (eg. by electroplating or electroless deposition) onto a support material.
The target comprises a 'support material' onto which is provided an outer coating of the surface solid material to be irradiated. The support material functions to provide effective cooling of the irradiated surface solid material during the irradiation, and permits separation of the radioisotope product, leaving the support material substantially unchanged, ready to be reused. The 'support material' comprises a material which is a good conductor of heat and/or electricity, ie. electroconductive such as silver. The support material is suitably of a shape and size that permits facile N,\Melbourne\Cases\Patent\51000-51999\P51497.AU\Specls\P51497.AU Specification 2006-12-1B.doc 21/12/06 production, as well as ease of attachment and detachment from the target assembly. A preferred shape of the support material is a plate.
The support material may comprise silver, but most preferably is made entirely of silver, since silver has advantages over copper. The non-radioactive copper of a copper support material can dissolve in acidic dissolution media (especially nitric acid).
This makes purification and isolation of the radioisotope more difficult, by eg.
increasing the viscosity of the dissolution medium, making solvent extraction of the radioisotope product more difficult. Hence one advantage of the use of silver as the support material is that silver does not dissolve readily in nitric acid, which makes subsequent purification of the radioisotope easier. Silver does, however, have a finite Ni\Melbourne\Cases\Patent\51000-51999\P51497.AU\Specis\P51497.AU Specification 2006-12-18.doc 21/12/06 4a WO 02/099816 PCT/US02/17678 solubility in concentrated hydrobromic acid, hence is less advantageous when the dissolution medium comprises concentrated hydrobromic acid.
In addition, when copper is the support material, and the target is subjected to proton bombardment, any protons which penetrate the surface solid material and are captured by the copper lead to the production of the potential impurity radioisotope At least a portion of any 65 Zn formed may dissolve in the dissolution medium, especially when the dissolution medium comprises aqueous acid, since Zn(0) dissolves in acid. 65 Zn has a half-life of 244 days, and hence both the copper target support material and the dissolution medium are, in effect, contaminated for a prolonged period. For the copper support plate, the period necessary to await radioactive decay of the 65 Zn is so long (minimum 10 half-lives), that corrosion of the copper support is likely to occur during the storage period to allow for decay. Hence, in effect the copper plate cannot be reused.
Also, any 6Zn contamination of the dissolution medium means that, even after the desired radioisotope product has been isolated or extracted, the dissolution medium must be kept for prolonged periods to await decay of the 65 Zn. In contrast, when the support material comprises silver, any protons captured by the silver generate the radioisotopes 05 Ag and o106Ag, which have half-lives of 41.3 and 8.5 days respectively. The result is that such silver target supports can be reused after an appropriate decay period (suitably of approximately one year).
Radioisotopes which can be prepared using the present process include 201 T1, 8 3 Rb, 88Y, 88Zr, 96 Tc, 97 Ru, 1 1 n, 67 Ga, 68 Ge, 57 Co, 1 03 Pd, 62 Cu and 67 Cu. The process is especially useful for 201 T1, 111n, 67Ga, 03 Pd, 57 Co and 62Cu, particularly 201 T1. The present invention may also be applied to the production of parent radioisotopes which decay to give positron emitters useful as radiopharmaceuticals, as used in so-called radioisotope generators. Suitable parent radioisotopes (with positron-emitting daughter) include: 8 2 Sr 82 Rb), 68Ge 68 Ga) and 62 Zn 62
CU).
When the target of the present invention includes a support material, the support material may optionally further comprise an 'inert layer' at its' outer surface. The inert layer suitably forms an unreactive layer interspersed between the surface solid material and the bulk of the support material. The inert layer comprises a material which is WO 02/099816 PCT/US02/17678 essentially insoluble in the dissolution medium, and thus protects the support material from partial dissolution when the irradiated target is processed. Preferably, the inert layer is provided at a thickness of less than 10 lan, to maximise the transparency of the inert layer to the charged particles used in the target irradiation, and hence minimise potential radioisotopic impurities arising due to capture of the charged particles by the inert layer itself. The inert layer functions to minimise dissolution of the target support material, together with any radioisotopic impurities formed via irradiation of the target support material (eg. the low energy gamma emitters 05 Ag or 10 6 mAg from a silver support material), into the dissolution medium. Any such dissolution could introduce potential impurities into the desired radioisotope product. Suitable inert layers comprise unreactive metals such as silver, gold, platinum, tungsten, tantalum or nickel. When the surface solid material is zinc, and the support material is copper, then nickel represents a preferred inert layer material. Preferably the inert layer comprises gold or silver, most preferably gold.
Gold has the advantage that it has greater passivity (ie. is less reactive chemically), and is most suitable for accepting the plated solid material of the target.
The sonication of the present invention may suitably be provided either by an ultrasonic probe which is immersed in the dissolution medium, or via external sonication of the container or bath containing the dissolution medium. Suitable sonication probes and sonication baths are commercially available.
The sonication apparatus converts the frequency of the power supply (eg. 50 to Hz) to high frequency 20 kHz electrical energy. This high frequency electrical energy is in turn converted via a transducer in the sonication apparatus to mechanical vibrations (either of the sonication probe or sonication bath). The mechanical vibrations are intensified by the sonication apparatus, thus creating pressure waves within the dissolution medium. These pressure waves form microbubbles in the dissolution medium, which expand during the negative pressure phase, and implode violently during the positive pressure phase. This phenomenon is known as cavitation, and causes the molecules in the dissolution medium to become intensely agitated. Suitable sonication probes have a level of cavitation at the horn tip of ca. 500 W/cmz, and a frequency of ca. 20 kHz, whereas suitable sonication baths may have a lower cavitation level of ca. 1 W/cm 2 at the horn tip, with a frequency of 36-42 kHz.
WO 02/099816 PCT/US02/17678 The sonication bath may comprise any material compatible with the dissolution medium, but is preferably TeflonTM. For the production of 201 T1, it has been found that there are separation distance effects (see Examples 1 and Thus, whilst the dissolution can be accelerated using an ultrasonic immersion probe, the irradiated 20 3 T-enriched target material in proximity to the probe was found to be dissolved smoothly, whereas those parts of the irradiated target more distant from the probe were harder to dissolve.
Thus, an immersion probe gives less uniform effects due to inhomogeneity, whereas ultrasonic baths give more uniform or homogeneous performance. It is therefore preferred that, when the size and geometry of the target is suitable for immersion of the whole target in a sonication bath, that such a sonication bath is used, ie. that external sonication of the dissolution medium is applied. External sonication also gives shorter dissolution times (see Example and is more convenient since there is no need to wash or decontaminate the immersion probe between preparations. Internal sonication may, however, be the best option when the size and geometry of the target is such that only a portion of the target can be immersed in a sonication bath.
The shorter dissolution times of the present invention are believed to result from improved kinetics of mixing the dissolution medium with the surface solid material, due to the cavitation of the dissolution medium. This confers particular improvements where the solubility of the irradiated target material in the dissolution medium is low, especially when it is necessary to dissolve the whole irradiated target. For the radioisotope product, any reduction in the target processing time results in an improved yield, because there is reduced loss due to radioactive decay during target processing. Clearly, this problem is exacerbated the shorter the half-life of the radioisotope, such as positron emitters which may have half-lives of the order of a few hours. Shorter processing times also reduce the risk of radiation dose to the operator, by reducing the time spent in target processing.
The process of the present invention also permits the use of much milder conditions for processing the irradiated target. This includes the use of more dilute solutions of acids and/or oxidants, lower temperatures, and shorter reaction times. In the case of a 20 3 T1 target for the production of 20T11, dilute aqueous nitric can be used as the dissolution medium instead of the conventional concentrated nitric acid solution (7 molar).
By the term 'dilute aqueous nitric acid' is meant an aqueous solution which is 0.5 to WO 02/099816 PCT/US02/17678 molar; preferably 0.8 to 1.2 molar, most preferably about 1 molar. The use of such dilute nitric acid results in a significant reduction in the undesirable dissolution of the silver or copper support of the irradiated target, and thus facilitates purification of the 201 T1 product.
The use of such milder dissolution media also has the advantage that it presents less of a corrosion hazard to the plant used to carry out the process.
In a second aspect, the present invention provides an improved process for the production of 201 T1. The improved process comprises the use of the sonication process as described above, together with a target which comprises 20 3 Tl as the surface solid material, where the target is irradiated with protons, and the dissolution medium is 'dilute nitric acid' as defined above. The support material preferably comprises silver, and most preferably is made entirely of silver metal. The use of silver as the support medium has the advantages described above, and the sonication method provides a shorter processing time, which gives improved yields of 201
T.
The radioisotope 201Tl illustrates an additional reason why shorter processing times are important. It is typically produced by proton beam irradiation of a 20 3 T-enriched solid target material, giving 201 Pb via a (p,3n) nuclear reaction, and subsequent extraction of the trace amount of 201 Pb produced. The 20 1 Pb initial product decays to 201 T1 with a half-life of 9.4 hours. This means that the 20 1 Pb must be chemically separated from the target 203 T1 before the desired 20 1 T1 can be obtained, since once the 201 T1 decay product has formed, it is chemically identical to the 203 T1 target material, and hence impossible to separate therefrom. Therefore it is critically important to decrease the loss of 20 1 T1 by shortening the time period necessary to achieve the separation of the 2 01 Pb initial product from the 203TI-enriched target material after the completion of the proton irradiation. Thus, in the case of 2 01 T, there is a chemical separation reason why shorter irradiated target dissolution times are important. Theoretical calculations indicate that every one hour increase in the processing period results in a 7.7 loss of yield of the final product 201 T1.
WO 02/099816 PCT/US02/17678 The invention is illustrated by the following Examples: Example 1: Sonication of 203 T1 Targets (Comparative Example).
Three identical silver target plates (ie. targets where solid silver is used as the support material, in the shape of a plate, without an inert layer) were electroplated with 1200mg of 20 3 T1, and immersed into a dissolution medium of 5% aqueous nitric acid solution (molarity ca. 1M) in three separate baths. The dissolution of the 203 Tl-thallium target material was carried out: without sonication, with a 100 W ultrasonic probe, with an ultrasonic bath (300 W).
Dissolution of all the 203 T1 target material took 20 minutes using internal sonication with the immersed probe and 13 minutes using external sonication via the bath Without sonication, ie. method the thallium target material could not be dissolved even at 30 minutes after the addition of the dilute nitric acid.
Example 2: Production of 20 1 T1 Using a Silver-containing Target.
A target having solid silver in the shape of a plate as the support material, and having 1200 mg of 20 3 T-enriched material plated thereon as the surface solid material, was attached to a target support assembly made of aluminium. The target was irradiated for 8 hours with protons, using a proton beam of about 30 MeV. The dissolution of the irradiated 20 3 T-enriched target material was carried out in an ultrasonic bath of 300 W sonication power, with 5% aqueous (ie. ca. IM) nitric acid as the dissolution medium.
The dissolution was complete in about 10 minutes. Hydrochloric acid was then added to the solution.. The separation of the 201 Pb radioisotope produced was achieved by solvent extraction of the irradiated 20 3 TI-enriched target material using diisopropylether.
WO 02/099816 PCT/US02/17678 The 201 Pb separation from the end of the proton bombardment took 1.6 hours to complete. Thus the total processing times compared to those without sonication are as follows: Without sonication Example 2 (Prior art) Dissolution time (min) 25-30 10-15 Evaporation time for the 40 0 nitric acid (min) Total processing time 2.4 hours 1.6 hours Thus, the method of the present invention saves ca. 0.8 hours.
The yield of radioactivity of 201T obtained via this method was 21.9 GBq per target plate at 15 hr after the completion of the 201 Pb separation.
Example 3: Production of 2 01 T1 using a Copper-containing Target.
A target plate made of copper as the support material, and having 203Tl-enriched target material plated onto its' surface was attached to a target support assembly made of aluminium for 2 01 T1 preparation, and irradiated with protons as per Example 2. After dissolution of the target material in a bath using 7 M nitric acid as the dissolution medium, the extraction of the irradiated 20 3TI-enriched target material was performed in the same way as Example 2; except that the separation sequence was as follows: evaporation of the nitric acid, (ii) dissolution of the precipitate (which includes a copper salt) with a small volume (ca. 10 ml) of aqua regia, (iii) addition of hydrochloric acid, and (iv) solvent extraction.
Using this method, it took 2.5 hours to complete the 20 'Pb separation from the end of the bombardment. The amount of radioactivity of 2 01 T1 obtained using this method was 18.8 GBq per plate at 15 hr after the separation of 201 Pb in this reference method. The lower yield of 201 T1 compared to Example 2 can be attributed to:the process period for the 20 'Pb separation is longer than that of Example 2 by 1 hour, the dissolution of significant amounts of the copper plate into the nitric acid dissolution medium reduces the efficiency of the process after the separation of the 201'Pb.
In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.
It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.
H:\adrianag\keep\2002310305speci.doc 31/07/06
Claims (10)
- 2. The process of claim 1, where only the surface solid material is dissolved.
- 3. The process of claim 1 or 2, where the irradiated target further comprises an inert layer interspersed between the surface solid material and the support material.
- 4. The process of any one of claims 1 3, where the irradiated target is irradiated with protons.
- 5. The process of any one of claims 1 4, where the dissolution medium comprises an oxidising agent. Ni\Melbourne\Casea\Patent\51000-51999\P51497.AU\Specis\P51497.AU Specification 2006-12-18.doc 21/12/06 12 O 6. The process of any one of claims 1 5, where the dissolution medium comprises N an acid.
- 7. The process of any one of claims 1 6, where the sonication is applied via a C 5 sonication probe immersed in the dissolution medium. O 8. The process of any one of claims 1 6, where the sonication is applied via 0 external sonication of the dissolution medium. (N,
- 9. The process of any one of claims 1 8, where the surface solid material C1 comprises molybdenum, nickel, rhodium, zinc, zinc oxide, copper, thallium, cadmium or gallium oxide. The process of any one of claims 1 9, where the radioisotope is 201, 83 Rb, 88Y, Zr, 9Tc, 9Ru, 62 Cu, 67 Cu, 'In, 6 7 Ga or 68 Ge.
- 11. A process for the production of a preparation containing a 20'T1 radioisotope from an irradiated target comprising: providing an irradiated target having a surface solid material which comprises 203T1 and 201 Pb on a support material; (ii) treating the irradiated target with a dissolution medium which comprises dilute aqueous nitric acid; (iii) applying sonication to the dissolution medium whilst it is in contact with the 23T1 and 20'Pb surface solid material of said irradiated target so that a portion of the 201 Pb radioisotope in the surface solid material dissolves in the dissolution medium; (iv) isolating the dilute nitric acid dissolution medium containing the 201Pb radioisotopes; subjecting the dissolution medium to purification, thereby producing a preparation containing the 201 T1 radioisotope; and (vi) optionally repeating steps (ii) to (iv). N,\Melbourne\Cases\Patent\51000-51999\P51497.AU\Specis\P51497.AU Specification 2006-12-18.doc 21/12/06 13
- 12. The process of claim 11, where the support material is silver.
- 13. The process of claim 11 or 12, where the sonication is applied via external sonication of the dissolution medium.
- 14. A process for the separation of a radioisotope from an irradiated target substantially as herein described with reference to either example 2 or 3. N:\Melbourne\CaaeB\Patent\S1000-51999\PS149AtI\pecis\PS1497.A Specification 2006-12-18.doc 21/12/06 14
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US29598001P | 2001-06-05 | 2001-06-05 | |
| US60/295,980 | 2001-06-05 | ||
| PCT/US2002/017678 WO2002099816A2 (en) | 2001-06-05 | 2002-06-04 | Process for the recovery of a radioisotope from an irradiated target |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| AU2002310305A1 AU2002310305A1 (en) | 2003-05-08 |
| AU2002310305B2 true AU2002310305B2 (en) | 2007-01-25 |
Family
ID=23140059
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU2002310305A Ceased AU2002310305B2 (en) | 2001-06-05 | 2002-06-04 | Process for the recovery of a radioisotope from an irradiated target |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JP4231779B2 (en) |
| KR (1) | KR100858265B1 (en) |
| CN (1) | CN1264170C (en) |
| AU (1) | AU2002310305B2 (en) |
| WO (1) | WO2002099816A2 (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4571109B2 (en) * | 2006-09-12 | 2010-10-27 | 行政院原子能委員会核能研究所 | Production process of radioisotope thallium-201 |
| JP4674727B2 (en) * | 2006-10-27 | 2011-04-20 | 行政院原子能委員会核能研究所 | Separation apparatus for radioisotope thallium-201 |
| EP2131369A1 (en) * | 2008-06-06 | 2009-12-09 | Technische Universiteit Delft | A process for the production of no-carrier added 99Mo |
| ES2674360T3 (en) * | 2013-06-27 | 2018-06-29 | Mallinckrodt Nuclear Medicine Llc | Germanium-68 generation process |
| CN108780672B (en) | 2016-04-21 | 2022-03-01 | 株式会社钟化 | Support substrate for radioisotope production, target plate for radioisotope production, and method for producing support substrate |
| CN108780670B (en) | 2016-04-28 | 2022-04-05 | 株式会社钟化 | Beam intensity conversion film and method for manufacturing beam intensity conversion film |
| EP3637437B1 (en) * | 2017-06-09 | 2022-11-16 | Kaneka Corporation | Target for proton-beam or neutron-beam irradiation and method for generating radioactive substance using same |
| EP3662728B1 (en) * | 2017-07-31 | 2024-05-08 | Triumf Inc. | System, apparatus and method for producing gallium radioisotopes on particle accelerators using solid targets and ga-68 composition produced by same |
| IT201700102990A1 (en) * | 2017-09-14 | 2019-03-14 | Istituto Naz Fisica Nucleare | METHOD FOR OBTAINING A SOLID TARGET FOR THE PRODUCTION OF RADIOPHARMACEUTICALS |
| JP6554753B1 (en) * | 2019-03-11 | 2019-08-07 | 株式会社京都メディカルテクノロジー | Technetium 99m isolation system and technetium 99m isolation method |
| JP7506055B2 (en) * | 2019-03-28 | 2024-06-25 | 住友重機械工業株式会社 | Target irradiation system and method for recovering radioisotopes from solid targets - Patents.com |
| US20210225546A1 (en) * | 2020-01-17 | 2021-07-22 | BWXT ITG Canada, Inc. | System and method for germanium-68 isotope production |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3007814A (en) * | 1956-10-04 | 1961-11-07 | Bendix Corp | Method of cleaning radioactive articles |
| US4297166A (en) * | 1978-02-20 | 1981-10-27 | Nihon Medi-Physics, Co., Ltd. | Thallium-carrying target material and its production |
| FR2600203A1 (en) * | 1986-06-17 | 1987-12-18 | Lemmens Godfried | Process for the decontamination of materials with radioactive contamination |
| FR2642889A1 (en) * | 1989-02-07 | 1990-08-10 | Doryokuro Kakunenryo | Process for cleaning containers contaminated with a radioactive substance |
-
2002
- 2002-06-04 AU AU2002310305A patent/AU2002310305B2/en not_active Ceased
- 2002-06-04 WO PCT/US2002/017678 patent/WO2002099816A2/en active Application Filing
- 2002-06-04 JP JP2003502839A patent/JP4231779B2/en not_active Expired - Fee Related
- 2002-06-04 CN CNB02813253XA patent/CN1264170C/en not_active Expired - Fee Related
- 2002-06-04 KR KR1020037015876A patent/KR100858265B1/en not_active IP Right Cessation
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3007814A (en) * | 1956-10-04 | 1961-11-07 | Bendix Corp | Method of cleaning radioactive articles |
| US4297166A (en) * | 1978-02-20 | 1981-10-27 | Nihon Medi-Physics, Co., Ltd. | Thallium-carrying target material and its production |
| FR2600203A1 (en) * | 1986-06-17 | 1987-12-18 | Lemmens Godfried | Process for the decontamination of materials with radioactive contamination |
| FR2642889A1 (en) * | 1989-02-07 | 1990-08-10 | Doryokuro Kakunenryo | Process for cleaning containers contaminated with a radioactive substance |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1522448A (en) | 2004-08-18 |
| KR20040028770A (en) | 2004-04-03 |
| KR100858265B1 (en) | 2008-09-11 |
| JP2004535288A (en) | 2004-11-25 |
| WO2002099816A2 (en) | 2002-12-12 |
| WO2002099816A3 (en) | 2003-05-08 |
| JP4231779B2 (en) | 2009-03-04 |
| CN1264170C (en) | 2006-07-12 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| AU2002310305B2 (en) | Process for the recovery of a radioisotope from an irradiated target | |
| Meijs et al. | Production of highly pure no-carrier added 89Zr for the labelling of antibodies with a positron emitter | |
| JP2023052329A (en) | Process for cyclotron production of technetium-99m, system, and apparatus | |
| RU2432632C2 (en) | METHOD OF EXTRACTING PURE 225Ac OBTAINED FROM IRRADIATED 226Ra TARGETS | |
| AU2002310305A1 (en) | Process for the recovery of a radioisotope from an irradiated target | |
| JP5197603B2 (en) | Methods for purifying radium from various sources | |
| KR102518999B1 (en) | Metal-molybdate and its preparation method | |
| KR102490805B1 (en) | A method for purifying a solution containing 226Ra, a method for producing a 226Ra target, and a method for producing 225Ac | |
| AU763373B2 (en) | Production of palladium-103 | |
| WO1995027987A1 (en) | Production of high specific activity copper -?67¿ | |
| US20060023829A1 (en) | Medical radioisotopes and methods for producing the same | |
| JP4690328B2 (en) | Radium target and production method thereof | |
| US7781744B2 (en) | Procedure for the preparation of radioisotopes | |
| EP1892728B1 (en) | Process of producing the radioisotope TL-201 | |
| RU2332735C1 (en) | Method of production of carrier-free radionuclide palladium-103 | |
| Mirzaii et al. | Electrodeposition iron target for the cyclotron production of 55 Co in labeling proteins | |
| FR2739216A1 (en) | METHOD OF TREATING METALLIC ALUMINUM-BASED FUELS AND / OR NUCLEAR TARGETS WITH TETRAMETHYLAMMONIUM HYDROXIDE SOLUTIONS | |
| US5057269A (en) | Production of aluminum-26 | |
| EP1883079A1 (en) | Procedure for the preparation of radioisotopes | |
| US20050252781A1 (en) | Method for packing electrochemically-deposited elements | |
| Sadeghi et al. | Electroplating/electrodissolution/recovery cycle for rhodium target used for an industrial scale cyclotron production of palladium-l03 | |
| Huszâr et al. | c H 3 MOSS r |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PC1 | Assignment before grant (sect. 113) |
Owner name: NIHON MEDI-PHYSICS CO., LTD. Free format text: FORMER APPLICANT(S): MEDI-PHYSICS, INC. |
|
| FGA | Letters patent sealed or granted (standard patent) | ||
| MK14 | Patent ceased section 143(a) (annual fees not paid) or expired |