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Production and Utilisation of Emerging Positron Emitters for Medical Applications with an Emphasis on Cu-64 and I-124
Closed for proposals
Project Type
Project Code
F22049CRP
1532Approved Date
Status
Start Date
Expected End Date
Completed Date
17 September 2013Description
There is a large growth in the number of medical cyclotrons and PET/PET-CT centres due to the proven high clinical utility of F-18 – FDG in cancer patients. This has led to the search for additional options to benefit from many other PET tracers which are in different stages of clinical evaluation. The IAEA has been assisting interested MS in this context with development of fluorine-18 products beyond FDG, as well as in using generator-produced gallium-68 products for PET imaging. In continuing with this approach, the present CRP seeks to enhance the utilisation of medical cyclotrons for production and utilisation of other emerging positron emitters, and in particular copper-64 (64Cu, 12.7 h) and iodine-124 (124I, 4.2 d). There are more than 500 cyclotron facilities world-wide and the number is growing every year. Many of these cyclotrons in the member states are in the energy range of 10-20 MeV, which is ideal for production of the above-mentioned PET radionuclides, and are generally operated for only limited periods of time every day. The CRP intends to develop better production routes and better separation and purification of these PET radionuclides so as to achieve high specific activity and chemical purity suitable for labelling molecules of medical interest and also enable fruitful utility of the spare capacity available in the medical cyclotron centres.
The development of new radiopharmaceuticals containing relatively longer-lived PET radionuclides, such as 124I and 64Cu, has received considerable attention as they can be routinely used for diagnosis or for evaluation of efficacy of radiotherapy. Currently, there are a limited number of 64Cu radiopharmaceuticals like 64Cu-ATSM that have been sufficiently developed for human studies. In view of the advantages of the versatile chemistry of copper and nuclear characteristics of 64Cu, as well as the ability to combine well-known merits of radioiodine with positron emitting feature of 124I, the scope for developing and deploying new PET tracers is very high. Research towards the development of additional 64Cu-complexes or chelator-biomolecule conjugates for imaging of diseases such as cancer, heart disease and neurological disorders is going on in several groups around the world. Similar developments with 124I are also evolving. The coordination of such on-going R&D through the proposed CRP would greatly aid in the further development of a few new radiopharmaceuticals incorporating these radionuclides for the diagnosis of specific diseases, as well as to provide improved dosimetry data for therapy with radionuclides based upon improved quantification of PET tracer distribution.
Objectives
To enhance and strengthen the expertise and capability of Member States in deploying emerging PET radioisotopes for medical and industrial applications in order to meet national needs as well as to assimilate new developments.
Specific objectives
1. Optimization of production methods for 64Cu.
2. Identification of suitable chelators for protein labelling with 64Cu.
3. Development of new 64Cu radiopharmaceuticals for oncological applications.
4. Development of the production method for 124I in large quantities via the 125Te(p,2n) reaction and application towards radiolabelling of biomolecules.
Impact
The participants of the CRP concluded that the project has helped to exchange valuable information and to become acquainted with other laboratories’ approaches and procedures and has stimulated cooperation between participating institutions as well as with relevant national counterparts. The specific objectives pursued by the CRP participants varied from country to country subject to the research priorities defined by the national teams, but the overall objectives of the CRP are well addressed.
While Cu-64 is not the only longer lived PET radioisotope, it is certainly the most well explored, and can be seen as a good starting point for solid targetry and transition metal radiochemical separations. As such, Cu-64 can be recommended as a research topic even in fairly new PET cyclotron facilities. The primary production route based on (p,n) reactions on Ni-64 require only very modest particle energy allowing all medical cyclotrons to obtain clinically applicable yields in a short time.
Relevance
The CRP is highly relevant to the project 2.5.1.1(I1.01) under the major programme 2. The CRP facilitated the information exchange on new developments and developed improved procedures for production of Cu-64 and I-124 in order to provide reliable production systems for radionuclides of the necessary high quality and high specific radioactivity for clinical applications.There is presently a rapid development of other radiometals for PET imaging, spanning the same or longer half-life ranges than the copper isotopes. It is still too early to decide if some of these isotopes, and most notably Zr-89, will in the end the replace Cu-64 for antibody and other protein imaging. For now, Cu-64 is the most explored and best documented choice for PET applications with half-life requirements beyond 2-3 hours.