Semi-remote production of [64Cu]CuCl2 and preparation of high specific activity [64Cu]Cu-ATSM for PET studies

Trace Metal Impurities Effects on the Formation of [64Cu]Cu-diacetyl-bis(N4-methylthiosemicarbazone) ([64Cu]Cu-ATSM)

[64Cu]Cu-diacetyl-bis(N4-methylthiosemicarbazone) ([64Cu]Cu-ATSM) is a radioactive hypoxia-targeting therapeutic agent being investigated in clinical trials for malignant brain tumors. For the quality management of [64Cu]Cu-ATSM, understanding trace metal impurities' effects on the chelate formation of 64Cu and ATSM is important. In this study, we conducted coordination chemistry studies on metal-ATSM complexes. First, the effects of nonradioactive metal ions (Cu2+, Ni2+, Zn2+, and Fe2+) on the formation of [64Cu]Cu-ATSM were evaluated. When the amount of Cu2+ or Ni2+ added was 1.2 mol or 288 mol, equivalent to ATSM, the labeling yield of [64Cu]Cu-ATSM fell below 90%. Little effect was observed even when excess amounts of Zn2+ or Fe2+ were added to the ATSM. Second, these metals were reacted with ATSM, and chelate formation was measured using ultraviolet-visible (UV-Vis) absorption spectra. UV-Vis spectra showed a rapid formation of Cu2+ and the ATSM complex upon mixing. The rate of chelate formation by Ni2+ and ATSM was lower than that by Cu-ATSM. Zn2+ and Fe2+ showed much slower reactions with the ATSM than Ni2+. Trace amounts of Ni2+, Zn2+, and Fe2+ showed little effect on [64Cu]Cu-ATSM' quality, while the concentration of impurity Cu2+ must be controlled. These results can provide process management tools for radiopharmaceuticals.

The role of chemistry in accelerator-based production and separation of radionuclides as basis for radiolabelled compounds for medical applications

Radiochemical separations used in large scale routine production of diagnostic and therapeutic radionuclides at a particle accelerator for patient care are briefly outlined. The role of chemistry at various stages of development of a production route of a novel radionuclide, namely nuclear data measurement, high-current targetry, chemical processing and quality control of the product, is discussed in detail. Special attention is paid to production of non-standard positron emitters (e.g. 44gSc, 64Cu, 68Ga, etc.) at a cyclotron and novel therapeutic radionuclides (e.g. 67Cu, 225Ac, etc.) at an accelerator. Some typical examples of radiochemical methods involved are presented.

Electrochemical deposition of nickel targets from aqueous electrolytes for medical radioisotope production in accelerators: a review

This paper reviews reported methods of the electrochemical deposition of nickel layers which are used as target materials for accelerator production of medical radioisotopes. The review focuses on the electrodeposition carried out from aqueous electrolytes. It describes the main challenges related to the preparation of suitable Ni target layers, such as work with limited amounts of expensive isotopically enriched nickel; electrodeposition of sufficiently thick, smooth and free of cracks layers; and recovery of unreacted Ni isotopes from the irradiated targets and from used electrolytic baths.

Development of novel radionuclides for medical applications

Medical radionuclide production technology is well established. There is, however, a constant need for further development of radionuclides. The present efforts are mainly devoted to nonstandard positron emitters (eg, ⁶⁴ Cu, ⁸⁶ Y, ¹²⁴ I, and ⁷³ Se) and novel therapeutic radionuclides emitting low-range β^- particles (eg, ⁶⁷ Cu and ¹⁸⁶ Re), conversion or Auger electrons (eg, ^117m Sn and ⁷⁷ Br), and α particles (eg, ²²⁵ Ac). A brief account of various aspects of development work (ie, nuclear data, targetry, chemical processing, and quality control) is given. For each radionuclide under consideration, the status of technology for clinical scale production is discussed. The increasing need of intermediate-energy multiple-particle accelerating cyclotrons is pointed out.

Pharmacokinetics and microbiodistribution of 64Cu-labeled collagen-binding peptides in chronic myocardial infarction

OBJECTIVES

The aim of the study is to evaluate the pharmacokinetics and microbiodistribution of Cu-labeled collagen-binding peptides.

METHODS

The affinity constant (KD), association (ka), and dissociation rate constant (kd) for the peptide collagelin or its analog (named CRPA) binding to collagen were measured by biolayer interferometric analysis. Rats (n=4-5) with myocardial infarction or normal were injected intravenously with the Cu-labeled peptides or Cu-DOTA as a control. Dynamic PET imaging was performed for 60 min at 7-8 weeks after infarct. Fluorine-18 fluorodeoxyglucose PET imaging was performed to identify the viable myocardium. To validate the PET images, slices of heart samples from the base to the apex were analyzed using autoradiography and histology.

RESULT

The peptides bound to collagen with a KD of ∼0.9 µmol/l. The Cu-peptides and Cu-DOTA accumulated in the infarct area (confirmed by autoradiography and histology images) within 1 min of injection and were excreted rapidly through the renal system. The blood clearance curves were biphasic with elimination half-lives of 21.9±2.4, 26.2±4.6, and 21.2±2.1 min for Cu-CRPA, Cu-collagelin, and the control Cu-DOTA, respectively. The clearance half-lives from the focal fibrotic tissue (24.1±1.5, 25.6±8.0, and 21.4±1.3 min, respectively) and remote myocardium (20.8±0.7, 21.0±5.5, and 19.1±2.4 min, respectively) were not significantly different. The uptake ratios of infarct-to-remote myocardium (1.93±0.18, 2.15±0.38, and 1.88±0.08, respectively) for Cu-CRPA, Cu-collagelin, and Cu-DOTA remained stable for the time period between 10 and 60 min.

CONCLUSION

The distribution of the Cu-collagelin probes corresponds to the heterogeneous distribution of expanded extracellular space in the setting of myocardial infarction. The overall washout rate from the fibrous tissue was determined by the slow washout rate (t1/2≥20 min) of the peptides from the extracellular space to the vasculature, not by the dissociation rate (t1/2<2 min) of the Cu-peptides from collagen.

Copper-64 Radiopharmaceuticals for Oncologic Imaging

The positron emitting radionuclide (64)Cu has a radioactive half-life of 12.7 hours. The decay characteristics of (64)Cu allow for PET images that are comparable in quality to those obtained using (18)F. Given the longer radioactive half-life of (64)Cu compared with (18)F and the versatility of copper chemistry, copper is an attractive alternative to the shorter-lived nuclides for PET imaging of peptides, antibodies, and small molecules that may require longer circulation times. This article discusses a number of copper radiopharmaceuticals, such as Cu-ATSM, that have been translated to the clinic and new developments in copper-based radiopharmaceuticals.

64Cu-DOTA as a surrogate positron analog of Gd-DOTA for cardiac fibrosis detection with PET: pharmacokinetic study in a rat model of chronic MI

OBJECTIVES

The aim of this study was to investigate the pharmacokinetics of (64)Cu-DOTA (1,4,7,10-azacyclododecane-N,N',N'',N'''-tetraacetic acid), a positron surrogate analog of the late gadolinium (Gd)-enhancement cardiac magnetic resonance agent, Gd-DOTA, in a rat model of chronic myocardial infarction (MI) and its microdistribution in the cardiac fibrosis by autoradiography.

METHODS

DOTA was labeled with (64)Cu-acetate. CD rats (n=5) with MI by left anterior descending coronary artery ligation and normal rats (n=6) were injected intravenously with (64)Cu-DOTA (18.5 MBq, 0.02 mmol DOTA/kg). Dynamic PET imaging was performed for 60 min after injection. (18)F-Fluorodeoxyglucose ([(18)F]-FDG) PET imaging was performed to identify the viable myocardium. For the region of interest analysis, the (64)Cu-DOTA PET image was coregistered to the [(18)F]-FDG PET image. To validate the PET images, slices of heart samples from the base to the apex were analyzed using autoradiography and by histological staining with Masson's trichrome.

RESULTS

(64)Cu-DOTA was rapidly taken up in the infarct area. The time-activity curves demonstrated that (64)Cu-DOTA concentrations in the blood, fibrotic tissue, and perfusion-rich organs peaked within a minute post injection; thereafter, it was rapidly washed out in parallel with blood clearance and excreted through the renal system. The blood clearance curve was biphasic, with a distribution half-life of less than 3 min and an elimination half-life of ∼21.8 min. The elimination half-life of (64)Cu-DOTA from the focal fibrotic tissue (∼22.4 min) and the remote myocardium (∼20.1 min) was similar to the blood elimination half-life. Consequently, the uptake ratios of focal fibrosis-to-blood and remote myocardium-to-blood remained stable for the time period between 10 and 60 min. The corresponding ratios obtained from images acquired from 30 to 60 min were 1.09 and 0.59, respectively, indicating that the concentration of (64)Cu-DOTA in the focal fibrosis was 1.85 (1.09/0.59) times greater than that in the remote myocardium. Thus, this finding indicates that the extracellular volume fraction was 1.85 times greater in the focal fibrosis than in the remote myocardium. The accumulation of (64)Cu-DOTA in fibrotic tissue was further supported by autoradiography and histology images. The autoradiography images of (64)Cu-DOTA in the fibrotic tissues were qualitatively superimposed over the histology images of the fibrotic tissues. The histology images of the infarct areas were characterized by a heterogeneous distribution of thin bands of fibrotic collagen, myocytes, and expanded extracellular space.

CONCLUSION

(64)Cu-DOTA is a useful surrogate positron analog of Gd-DOTA, enabling quantitative measurement of the uptake values in fibrotic tissues by dynamic PET imaging and calculation of the extracellular volume fractions of the fibrotic tissues. At a microscopic level, the distribution of (64)Cu-DOTA is nonuniform, corresponding to the heterogeneous distribution of expanded extracellular space in the setting of MI.

The present and future of medical radionuclide production

Medical radionuclide production technology is well established. Both reactors and cyclotrons are utilized for production; the positron emitters, however, are produced exclusively using cyclotrons. A brief survey of the production methods of most commonly used diagnostic and therapeutic radionuclides is given. The emerging radionuclides are considered in more detail. They comprise novel positron emitters and therapeutic radionuclides emitting low-range electrons and α-particles. The possible alternative production routes of a few established radionuclides, like 68Ga and 99mTc, are discussed. The status of standardisation of production data of the commonly used as well as of some emerging radionuclides is briefly mentioned. Some notions on anticipated future trends in the production and application of radionuclides are considered.

Development of copper based drugs, radiopharmaceuticals and medical materials

Copper is one of the most interesting elements for various biomedical applications. Copper compounds show vast array of biological actions, including anti-inflammatory, anti-proliferative, biocidal and other. It also offers a selection of radioisotopes, suitable for nuclear imaging and radiotherapy. Quick progress in nanotechnology opened new possibilities for design of copper based drugs and medical materials. To date, copper has not found many uses in medicine, but number of ongoing research, as well as preclinical and clinical studies, will most likely lead to many novel applications of copper in the near future.

Improvement of CXCR4 tracer specificity for PET imaging

Tumors expressing the chemokine receptor CXCR4 have been reported to be more aggressive and to produce more metastatic seeding in specific organs, such as the bone marrow. However, evaluation of tumors for CXCR4 expression requires testing of ex vivo biopsy samples, and is not routinely done in cancer management. In prior work to address this issue, we and others have developed tracers for positron emission tomography (PET) that targeted CXCR4, but in addition to binding to CXCR4 these tracers also bound to red blood cells (and to other unrelated targets) in vivo. Here we report two new tracers based on the CXCR4 peptide antagonist 4F-benzoyl-TN14003 (T140) that bind to CXCR4, but not to undesired targets. These tracers, NOTA-NFB and DOTA-NFB, show slight reductions in both 1) binding affinities for CXCR4 and 2) inhibition of CXCL12 induced migration, compared to T140, in vitro. Both NOTA-NFB and DOTA-NFB specifically accumulate in CXCR4-positive, but not CXCR4-negative, tumor xenografts in mice and allow clear visualization of CXCR4 expression by PET. Evaluation of NOTA-NFB and DOTA-NFB for their potential to mobilize immune cells and progenitor cells from the bone marrow to the peripheral blood revealed slightly reduced, but still comparable, results to the parent molecule T140. The tracers reported here may allow the evaluation of CXCR4 expression in primary tumors and metastatic nodules, and enable better informed, more personalized treatment for patients with cancer.

Development of novel positron emitters for medical applications: nuclear and radiochemical aspects

In molecular imaging, the importance of novel longer lived positron emitters, also termed as non-standard or innovative PET radionuclides, has been constantly increasing, especially because they allow studies on slow metabolic processes and in some cases furnish the possibility of quantification of radiation dose in internal radiotherapy. Considerable efforts have been invested worldwide and about 25 positron emitters have been developed. Those efforts relate to interdisciplinary studies dealing with basic nuclear data, high current charged particle irradiation, efficient radiochemical separation and quality control of the desired radionuclide, and recovery of the enriched target material for reuse. In this review all those aspects are briefly discussed, with particular reference to three radionuclides, namely 64Cu, 124I and 86Y, which are presently in great demand. For each radionuclide several nuclear routes were investigated but the ( p,n) reaction on an enriched target isotope was found to be the best for use at a small-sized cyclotron. Some other positron emitting radionuclides, such as 55Co, 76Br, 89Zr, 82mRb, 94mTc, 120I, etc., were also produced via the low-energy (p,n), (p,α) or (d,n) reaction. On the other hand, the production of radionuclides 52Fe, 73Se, 83Sr, etc. using intermediate energy (p,xn) or (d,xn) reactions needs special consideration, the nuclear data and chemical processing methods being of key importance. In a few special cases, a high intensity 3He- or α-particle beam could be an added advantage. The production of some potentially interesting positron emitters via generator systems, for example 44Ti/44Sc, 72Se/72As and 140N d/140Pr is considered. The significance of new generation high power accelerators is briefly discussed.

Highly stable acyclic bifunctional chelator for 64Cu PET imaging

Ligand L1, based on a pyridine scaffold, functionalized by two bis(methane phosphonate)aminomethyl groups, was shown to display a very high affinity towards Cu(II) (log K CuL=22.7) and selectivity over Ni(II), Co(II), Zn(II) and Ga(III) (Δ log K ML>4) as shown by the values of the stability constants obtained from potentiometric measurements. Insights into the coordination mode of the ligand around Cu(II) cation were obtained by UV-Vis absorption and EPR spectroscopies as well as density functional theory (DFT) calculations (B3LYP model) performed in aqueous solution. The results point to a pentacoordination pattern of the metal ion in the fully deprotonated [CuL1]6− species. Considering the beneficial thermodynamic parameters of this ligand, kinetic experiments were run to follow the formation of the copper(II) complexes, indicating a very rapid formation of the complex, appropriat e for 64Cu complexation. As L1 represents a particularly interesting target within the frame of 64Cu PET imaging, a synthetic protocol was developed to introduce a labeling function on the pyridyl moiety of L1, thereby affording L2, a potential bifunctional chelator (BFC) for PET imaging.

One step purification process for no-carrier-added 64Cu produced using enriched nickel target

Copper-64 has found many applications in positron emission tomography (PET). Its half-life allows to use it for dosimetric studies associated to copper-67 targeted radiotherapy in cancer treatment. The use of 64Ni(p,n)64Cu nuclear reaction is known to produce 64Cu in large amount and with a high specific activity. In this study, targets were obtained by electroplating onto a gold backing and a typical target irradiation uses 200ߙnA, 17ߙMeV protons during 30ߙmin. After irradiation, pure copper-64 is obtained using only one chromatographic column. Nickel-64 is removed in a first elution step and cobalt isotopes in a second one. The extraction yield for copper-64 is 9±23% and nickel and cobalt impurities are under the detection limit. A recovery process of nickel-64 has also been developed.

Charged particle induced reaction cross section data for production of the emerging medically important positron emitter64Cu: A comprehensive evaluation

The radionuclide64Cu (T1/2=12.7 h) is an important non-standard positron emitter, suitable for combining PET imaging and targeted therapy. Its production in no-carrier-added form is doneviacharged particle induced reactions, and considerable amount of cross section data are available in the literature. We evaluated seven reactions, namely64Ni(p,n)64Cu,64Ni(d, 2n)64Cu,68Zn(p, αn)64Cu,66Zn(p, 2n)64Cu,64Zn(d, 2p)64Cu,66Zn(p, α)64Cu andnatZn(d,x)64Cu. Data analysis was generally limited up to about 25 MeV and the consistency check of experimental data was carried out using the nuclear model codes STAPRE, EMPIRE and TALYS. In a few cases experimental data were available up to 100 MeV; the consistency check in the high energy region was done only using the code TALYS. A statistical procedure (supported by nuclear model calculations) was then used to fit the data. The derived recommended sets of data, together with 95% confidence limits, are reported. The integral yields calculated from those data are also given. A critical comparison of the various production routes of64Cu is presented. The64Ni(p,n)64Cu reaction, utilizing a highly enriched target, is the method of choice.

Positron emission intensities in the decay of64Cu,76Br and124I

The relatively long-lived positron emitters64Cu (t1/2= 12.7 h),76Br (t1/2= 16.2 h) and124I (t1/2= 4.18 d) are finding increasing applications in positron emission tomography (PET). For precise determination of their positron emission intensities, each radionuclide was preparedviaa charged particle induced reaction in a “no-carrier-added” form and with high radionuclidic purity. It was then subjected toγ-ray and X-ray spectroscopy as well as to anticoincidence beta andγγ-coincidence counting. The positron emission intensities measured were:64Cu (17.8 ± 0.4)%,76Br (58.2 ± 1.9)% and124I (22.0 ± 0.5)%. The intensity of the weak 1346 keVγ-ray emitted in the decay of64Cu was determined as (0.54 ± 0.03)%. Some implications of the precisely determined nuclear data are discussed.

Radiochemical studies relevant to the no-carrier-added production of 61,64Cu at a cyclotron

Copper-64 (t ½ = 12.7 h) is a promising cancer treatment radiotherapy agent and combines positron emission tomography (PET). It was produced utilizing the 64Ni(p,n) 64Cu nuclear reaction channel. Natural nickel was electroplated successfully, 48 μm thick, onto a gold-coated copper backing slab. Bombardment of nickel plated target was performed with 16 MeV protons at a current of 200 μA. Copper-64 together with copper-61 was separated from Ni and other non-isotopic impurities by ion exchange chromatography. The method of separation of radiocopper has been improved.

A novel method for n.c.a.64Cu production by the64Zn(d, 2p)64Cu reaction and dual ion-exchange column chromatography

A novel production method for n.c.a.64Cu based on deuteron irradiation of64Zn is presented. The production takes place through the64Zn(d, 2p)64Cu reaction using a deuteron beam of 19.5 MeV energy on highly enriched64Zn disks. An average yield over three irradiations of 31 MBq/μA h (850 μCi/μA h) and saturation yield of 575 MBq/μA (15.5 mCi/μA) at the end of the beam (EOB) was measured by γ-ray spectrometry. Two of the three runs, of low irradiation charge, were used for radiochemistry. The copper isotopes were separated from other radionuclidic impurities by the combination of cation and anion exchange chromatography. An average radiochemical yield of 90% was estimated for the two runs performed in this study, and the specific activity as determined using flame atomic absorption spectrometry was about 4 MBq/μg, 2 hours after EOB. An extrapolation of the present results to production conditions (50 μA, 10 h) indicates approximately 8 GBq/μg (220 mCi/μg) of specific activity. The overall uncertainty in these values is estimated to 15%.

Copper-64 radiopharmaceuticals for PET imaging of cancer: advances in preclinical and clinical research

Copper-64 (T(1/2) = 12.7 hours; beta(+), 0.653 MeV [17.8 %]; beta(-), 0.579 MeV [38.4 %]) has decay characteristics that allow for positron emission tomography (PET) imaging and targeted radiotherapy of cancer. The well-established coordination chemistry of copper allows for its reaction with a wide variety of chelator systems that can potentially be linked to peptides and other biologically relevant small molecules, antibodies, proteins, and nanoparticles. The 12.7-hours half-life of 64Cu provides the flexibility to image both smaller molecules and larger, slower clearing proteins and nanoparticles. In a practical sense, the radionuclide or the 64Cu-radiopharmaceuticals can be easily shipped for PET imaging studies at sites remote to the production facility. Due to the versatility of 64Cu, there has been an abundance of novel research in this area over the past 20 years, primarily in the area of PET imaging, but also for the targeted radiotherapy of cancer. The biologic activity of the hypoxia imaging agent, 60/64Cu-ATSM, has been described in great detail in animal models and in clinical PET studies. An investigational new drug application for 64Cu-ATSM was recently approved by the U.S. Food and Drug Administration (FDA) in the United States, paving the way for a multicenter trial to validate the utility of this agent, with the hopeful result being FDA approval for routine clinical use. This article discusses state-of-the-art cancer imaging with 64Cu radiopharmaceuticals, including 64Cu-ATSM for imaging hypoxia, 64Cu-labeled peptides for tumor-receptor targeting, (64)Cu-labeled monoclonal antibodies for targeting tumor antigens, and 64Cu-labeled nanoparticles for cancer targeting. The emphasis of this article will be on the new scientific discoveries involving (64)Cu radiopharmaceuticals, as well as the translation of these into human studies.

Alternative method for (64)Cu radioisotope production

The method for (64)Cu production based on a (64)Ni target using an 18MeV proton energy beam was developed. The studies on the optimisation of targetry for the 18MeV proton bombardments were performed in terms of the cost-effective target utilisation and purity of the (64)Cu product. The thickness-specific (64)Cu yield (microCi/(microA x microm)) was introduced into the optimisation calculation with respect to cost-effective target utilisation. A maximum target utilisation efficacy factor (TUE) was found for the proton energy range of 2.5-13MeV with corresponding target thickness of 36.2microm. With the optimised target thickness and proton energy range, the (64)Ni target thickness saving of 45.6% was achieved, while the overall (64)Cu yield loss is only 23.9%, compared to the use of the whole effective proton energy range of 0-18MeV with target thickness of 66.6microm. This optimisation has the advantage of reducing the target amount to a reasonable level, and therefore the cost of the expensive (64)Ni target material. The (64)Ni target electroplated on the Au-Tl multi layer coated Cu-substrate was a new and competent design for an economic production of high quality (64)Cu radioisotope using an 18MeV proton energy cyclotron or a 30MeV cyclotron with proton beam adjustable to 18MeV. In this design, the Au coating layer plays a role of protection of "cold" Cu leakage from the Cu substrate and Tl serves to depress the proton beam energy (from 18MeV to the energy optimised value 13MeV). The ion exchange chromatographic technique with a gradient elution was applied to improve the (64)Cu separation with respect to reducing the processing time and control of (64)Cu product quality.

Cu-ATSM: a radiopharmaceutical for the PET imaging of hypoxia

Copper(II)-diacetyl-bis(N(4)-methylthiosemicarbazone), Cu-ATSM, labeled with a positron emitting isotope of copper ((60)Cu, (61)Cu, (62)Cu or (64)Cu) has been shown, in vitro and in vivo, to be selective for hypoxic tissue. In silico studies have explored the mechanism of its hypoxia selectivity, and clinical studies with this agent have shown non-invasive imaging data that is predictive of a cancer patients' response to conventional therapy. This Perspective discusses the evolution of Cu-ATSM, how its selectivity can be improved upon, and where this metal-ligand platform could be taken in the future.

Production and separation of non-carrier-added 86Y from enriched 86Sr targets

The metallic radionuclide (86)Y was produced by irradiation of enriched (86)SrCO(3) on a low-energy proton-only cyclotron. Irradiations up to 20 microA for 2h were performed with 11 MeV protons using a water-cooled target mounting with circulating chilled helium. Experimental thick target yields of 26.7 mCi/microA yielded 24 mCi of (86)Y in 2h of bombardment at 10 microA. The difference in solubility products between Y(OH)(3) and Sr(OH)(2) allows the separation of (86)Y from an alkaline strontium solution by using filter paper with an overall yield of 88 +/- 3%. The concentration of Sr in the final product was found to be on the order of 15 ppm when using 200mg of target material as determined by ICP-MS analysis. The reactivity of (86)Y was determined to be on the order of 1.5 +/- 0.8 Ci/micromol of DOTA. The enriched target material was recovered and converted to its original chemical form with an overall efficiency >90%.

Simultaneous production of high specific activity 64Cu and 61Co with 11.4 MeV protons on enriched 64Ni nuclei

The (64)Cu and (61)Co radionuclides were produced simultaneously by irradiation of enriched (64)Ni on a low energy proton-only cyclotron. Nickel targets were prepared by electrodeposition of enriched (64)Ni (>95%) on Au backing at thicknesses of 25-225 mg/cm(2) with efficiencies >99%. Irradiations up to 30 microA for 8h were performed with 11.4 MeV protons using a water-cooled target mounting. Radiochemical separation of (64)Cu and (61)Co from (64)Ni was performed by chromatography of the chlorocomplexes in a single step using an anion exchange resin column with a yield >95%. Using this method, the Ni target material was recovered and re-plated for subsequent production runs with an overall efficiency >96%. The excitation function for the (64)Ni(p,n)(64)Cu reaction was measured and compared with published values. Experimental thick target saturation yields of 159 mCi/microA for (64)Cu and 715 microCi/microA for (61)Co were achieved. Typical specific activities of (64)Cu were found to be 18.8+/-3.3 Ci/micromol.