Browsing by Author "Alves, Francisco"
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- 45Ti - Titanium: from cyclotron production to potential applications evaluationPublication . Costa, Pedro; Metello, Luís F.; Cunha, Lídia; Lass, Piotr; Currie, Geoff; Johnson, Richard R.; Gelbart, W.; Obermair, J.; Artner, Christoph; Alves, Francisco; Naia, M. DuarteIntroduction: Thousands of radioisotopes are known and virtually all may be artificially produced, however clinical applications of PET imaging are mainly based on 18F, 11C, 13N and 68Ga. This trend could change in the near future, since several groups worldwide are busy developing very promising new entities aiming to contribute for spreading the use and efficacy of clinical diagnostic using Nuclear Medicine imaging techniques. Our group is developing 45Ti-Titanium, assuming it as a potential candidate, since presenting interesting properties: physical half-life of 3.09h, together with relevant chemical properties, that enable radiolabelling with bifunctional chelates, ligands or could even be useful for studies concerning the distribution of new titanium-based chemotherapy drugs or titanium oxide nanoparticles. Considering that data characterizing excitation functions is necessary for radionuclide optimal production, this work aims to disseminate results regarding the determination of excitation function of 45Sc(p,n)45Ti reaction, studied as a potential route to produce 45Ti in low energy cyclotrons.
- Application of Monte Carlo simulation codes to plan an activation experiment in Scandium-45 targetsPublication . Costa, Pedro; Metello, Luís F.; Alves, Francisco; Naia, M. DuarteData characterizing excitation functions of nuclear reactions are necessary for different applications, with the process of radionuclide production being assumed as a relevant example. This is the only way to define and optimize technical parameters involved in such a process. However, nuclear activation experimental studies are sometimes difficult to implement, and care should be taken before its execution, in order to obtain all relevant data, while correctly planning the experiences. In this context, Monte Carlo simulation tools are widely applied to overtake such difficulties. This work describes a case-study aiming to characterize nuclear reactions excitation functions induced by a proton beam and its interaction with a Scandium target – a specific situation that is not yet completely characterized and that might be of relevance, since it could be useful to produce medically relevant radionuclides (eg. Titanium-45).
- Cyclotech - contribution to solve the Technetium shortage by using low energy medical cyclotronsPublication . Metello, Luís F.; Gelbart, W.; Benedict, Malcom; Cunha, Lídia; Alves, Francisco; Johnson, Richard R.This paper presents work in progress, to develop an efficient and economic way to directly produce Technetium 99metastable (99mTc) using low-energy cyclotrons. Its importance is well established and relates with the increased global trouble in delivering 99mTc to Nuclear Medicine Departments relying on this radioisotope. Since the present delivery strategy has clearly demonstrated its intrinsic limits, our group decided to follow a distinct approach that uses the broad distribution of the low energy cyclotrons and the accessibility of Molybdenum 100 (100Mo) as the Target material. This is indeed an important issue to consider, since the system here presented, named CYCLOTECH, it is not based on the use of Highly Enriched (or even Low Enriched) Uranium 235 (235U), so entirely complying with the actual international trends and directives concerning the use of this potential highly critical material. The production technique is based on the nuclear reaction 100Mo (p,2n) 99mTc whose production yields have already been documented. Until this moment two Patent requests have already been submitted (the first at the INPI, in Portugal, and the second at the USPTO, in the USA); others are being prepared for submission on a near future. The object of the CYCLOTECH system is to present 99mTc to Nuclear Medicine radiopharmacists in a routine, reliable and efficient manner that, remaining always flexible, entirely blends with established protocols. To facilitate workflow and Radiation Protection measures, it has been developed a Target Station that can be installed on most of the existing PET cyclotrons and that will tolerate up to 400 μA of beam by allowing the beam to strike the Target material at an adequately oblique angle. The Target Station permits the remote and automatic loading and discharge of the Targets from a carriage of 10 Target bodies. On other hand, several methods of Target material deposition and Target substrates are presented. The object was to create a cost effective means of depositing and intermediate the target material thickness (25 - 100μm) with a minimum of loss on a substrate that is able to easily transport the heat associated with high beam currents. Finally, the separation techniques presented are a combination of both physical and column chemistry. The object was to extract and deliver 99mTc in the identical form now in use in radiopharmacies worldwide. In addition, the Target material is recovered and can be recycled.
- Cyclotron produced 45Ti-Titanium: why & how… so WHY NOT?Publication . Costa, Pedro; Metello, Luís F.; Cunha, Lídia; Johnson, Richard R.; Mattei, Lidia; Gelbart, W.; Obermair, J.; Dietl, B.; Nauschnig, R.; Artner, Christoph; Lass, Piotr; Currie, Geoff; Carmo, Sérgio; Alves, Francisco; Naia, M. DuarteThere are many different radioisotopes well known and characterized for medical use, with almost all of them able to be artificially produced. Nevertheless, routine clinical applications of PET imaging are still based on 18F, in excess of 97% of the cases, with 11C, 13N and 68Ga sharing the few remaining situations. This trend could change in the – hopingly near – future, since several groups worldwide are busy developing very promising new processes using less conventional radionuclides, aiming to contribute for spreading the use and efficacy of clinical diagnostic using Nuclear Medicine imaging techniques, evolving more and more in the direction of personalized medicine, an worldwide growing societal request. Our group is busy studying 45Ti, interested by its many interesting properties and assuming it as a high-potential candidate: in fact 45Ti presents a physical half-life of 3.09h (50% higher than 18F) together with relevant chemical properties, that enable radiolabelling with bifunctional chelates, ligands or even to radiolabel titanium (di)oxide nanoparticles. Considering that data characterizing excitation functions are mandatory for radionuclide optimal production, the present work refers to our results regarding the 45Sc(p,n)45Ti nuclear reaction, being studied as a potential route to efficiently produce 45Ti in low energy cyclotrons.
- Cyclotron Production of Unconventional Radionuclides for PET Imaging: the Example of Titanium-45 and Its ApplicationsPublication . Costa, Pedro; Metello, Luís; Alves, Francisco; Naia, M. DuartePositron emitting radionuclides are used to label different compounds, allowing the study of the major biological systems using PET (positron emission tomography) imaging. Although there are several radionuclides suited for PET imaging, routine clinical applications are still based on a restrict group constituted by 18F, 11C, and, more recently, 68Ga. However, with the enlarged availability of low-energy cyclotrons and technical improvements in radionuclide production, the use of unconventional radionuclides is progressively more common. Several examples of unconventional radionuclides for PET imaging are being suggested, and 45Ti could be suggested as a model, due to its interesting properties such as its abundant positron emission (85%), reduced positron energy (β+ endpoint energy = 1040 keV), physical half-life of 3.09 h, and interesting chemical properties. This review aims to introduce the role of cyclotrons in the production of unconventional radionuclides for PET imaging while using 45Ti as an example to explore the potential biomedical applications of those radionuclides in PET imaging
- Experimental results on excitation functions for 45Ti direct production on low energy - medical - cyclotronsPublication . Costa, Pedro; Metello, Luís F.; Cunha, Lídia; Johnson, Richard R.; Gelbart, W.; Obermair, J.; Artner, Christoph; Carmo, Sérgio; Alves, Francisco; Naia, M. Duarte
- Should new Nuclear Reactors be considered as an option to solve Technetium shortage problem?Publication . Metello, Luís F.; Cunha, Lídia; Costa, Pedro; Vieira, Domingos; Alves, Francisco; Botelho, Maria Filomena; Gelbart, W.; Artner, Christoph; Nader, Michael; Schibli, Roger; Jensen, MikaelWorldwide, more than 80% of Nuclear Medicine procedures use a radiotracer produced through a 99Mo/99mTc generator - 99mTc – Technetium 99metastable. Most of the radiochemistry and equipments is optimized for this radioisotope characteristics already for more than 35 years, making it very difficult to replace. Worldwide production of 99Mo is based essentially with only five Nuclear Reactors that are becoming obsolete and fragile with aging, shutting down more and more frequently as they approach the end of their shelf-life. Seeking for solutions, some Governments – and the EU – plan to build new dedicated Nuclear Reactor(s). Our work defends another option.
- The use of radiolabeled nanoparticles for biomedical imagingPublication . Costa, Pedro; Metello, Luís F.; Alves, Francisco; Naia, M. DuarteIntroduction: In the last years, the practice of medicine is being changing with a special emphasis on the application of technological innovations where medical imaging modalities play an important role. Between several imaging modalities, Molecular Imaging (that is essentially based on Nuclear Medicine) is one of the most interesting solutions. On the other hand, assuming that nanoparticles are being studied as drug delivery systems, its application as vectors for radionuclide-based imaging is in a clear growing.
- Using Monte Carlo to approach 45Ti direct production on low energy - medical - cyclotronsPublication . Costa, Pedro; Cunha, Lídia; Johnson, Richard R.; Gelbart, W.; Artner, Christoph; Alves, Francisco; Naia, M. Duarte; Metello, Luís F.