Lebeda O.,Academy of Sciences of the Czech Republic |
van Lier E.J.,Advanced Cyclotron Systems Inc. |
Stursa J.,Academy of Sciences of the Czech Republic |
Ralis J.,Academy of Sciences of the Czech Republic |
Zyuzin A.,Advanced Cyclotron Systems Inc.
Nuclear Medicine and Biology | Year: 2012
Introduction: The commercial viability of cyclotron-produced 99mTc as an alternative to generator-produced 99mTc depends on several factors. These include: production yield, ease of target processing and recycling of 100Mo, radiochemical purity, specific activity as well as the presence of other radionuclides, particularly various Tc radioisotopes that cannot be separated chemically and will remain in the final clinical preparation. These Tc radionuclidic impurities are derived from nuclear interactions of the accelerated protons with other stable Mo isotopes present in the enriched 100Mo target. The aim of our study was to determine experimentally the yields of Tc radioisotopes produced from these stable Mo isotopes as a function of incident beam energy in order to predict radionuclidic purity of 99mTc produced in highly enriched 100Mo targets of known isotopic composition. Methods: Enriched molybdenum targets of 95Mo, 96Mo, 97Mo, 98Mo and 100Mo were prepared by pressing powdered metal into an aluminum target support. The thick targets were bombarded with 10 to 24MeV protons using the external beam line of the U-120M cyclotron of the Nuclear Physics Institute, Řež. The thick target yields of 94Tc, 94mTc, 95Tc, 95mTc, 96m+gTc and 97mTc were derived from their activities measured by γ spectrometry using a high purity Ge detector. These data were then used to assess the effect of isotopic composition of highly enriched 100Mo targets on the radionuclidic purity of 99mTc as a function of proton beam energy. Estimates were validated by comparison to measured activities of Tc radioisotopes in proton irradiated, highly enriched 100Mo targets of known isotopic composition. Results: The measured thick target yields of 94Tc, 94mTc, 95Tc, 95mTc, 96m+gTc and 97mTc correspond well with recently published values calculated via the EMPIRE-3 code. However, the measured yields are more favourable with regard to achievable radionuclidic purity of 99mTc. Reliability of the measured thick target yields was demonstrated by comparison of the estimated and measured activities of 94Tc, 95Tc, 95mTc, and 96m+gTc in highly enriched 100Mo (99%) targets that showed good agreement, with maximum differences within estimated uncertainties. Radioisotopes 94mTc and 97mTc were not detected in the irradiated 100Mo targets due to their low activities and measurement conditions; on the other hand we detected small amounts of the short-lived positron emitter 93Tc (T1/2=2.75h). In addition to 99mTc and trace amounts of the various Tc isotopes, significant activities of 96Nb, 97Nb and 99Mo were detected in the irradiated 100Mo targets. Conclusions: Radioisotope formation during the proton irradiation of Mo targets prepared from different, enriched stable Mo isotopes provides a useful data base to predict the presence of Tc radionuclidic impurities in 99mTc derived from proton irradiated 100Mo targets of known isotopic composition. The longer-lived Tc isotopes including 94Tc (T1/2=4.883h), 95Tc (T1/2=20.0h), 95mTc (T1/2=61 d), 96m+gTc (T1/2=4.24 d) and 97mTc (T1/2=90 d) are of particular concern since they may affect the dosimetry in clinical applications. Our data demonstrate that cyclotron production of 99mTc, using highly enriched 100Mo targets and 19-24MeV incident proton energy, will result in a product of acceptable radionuclidic purity for applications in nuclear medicine. © 2012 Elsevier Inc..
Selivanova S.V.,Sherbrooke Molecular Imaging Center |
Selivanova S.V.,Université de Sherbrooke |
Lavallee E.,Sherbrooke Molecular Imaging Center |
Senta H.,Sherbrooke Molecular Imaging Center |
And 12 more authors.
Journal of Nuclear Medicine | Year: 2015
Cyclotron production of 99mTc is a promising route to supply 99mTc radiopharmaceuticals. Higher 99mTc yields can be obtained with medium-energy cyclotrons in comparison to those dedicated to PET isotope production. To take advantage of this capability, evaluation of the radioisotopic purity of 99mTc produced at medium energy (20-24 MeV) and its impact on image quality and dosimetry was required. Methods: Thick 100Mo (99.03% and 99.815%) targets were irradiated with incident energies of 20, 22, and 24 MeV for 2 or 6 h. The targets were processed to recover an effective thickness corresponding to approximately 5-MeV energy loss, and the resulting sodium pertechnetate 99mTc was assayed for chemical, radiochemical, and radionuclidic purity. Radioisotopic content in final formulation was quantified using g-ray spectrometry. The internal radiation dose for 99mTc-pertechnetate was calculated on the basis of experimentally measured values and biokinetic data in humans. Planar and SPECT imaging were performed using thin capillary and water-filled Jaszczak phantoms. Results: Extracted sodium pertechnetate 99mTc met all provisional quality standards. The formulated solution for injection had a pH of 5.0-5.5, contained greater than 98% of radioactivity in the form of pertechnetate ion, and was stable for at least 24 h after formulation. Radioisotopic purity of 99mTc produced with 99.03% enriched 100Mo was greater than 99.0% decay corrected to the end of bombardment (EOB). The radioisotopic purity of 99mTc produced with 99.815% enriched 100Mo was 99.98% or greater (decay corrected to the EOB). The estimated dose increase relative to 99mTc without any radionuclidic impurities was below 10% for sodium pertechnetate 99mTc produced from 99.03% 100Mo if injected up to 6 h after the EOB. For 99.815% 100Mo, the increase in effective dose was less than 2% at 6 h after the EOB and less than 4% at 15 h after the EOB when the target was irradiated at an incident energy of 24 MeV. Image spatial resolution and contrast with cyclotron-produced 99mTc were equivalent to those obtained with 99mTc eluted from a conventional generator. Conclusion: Clinical-grade sodium pertechnetate 99mTc was produced with a cyclotron at medium energies. Quality control procedures and release specifications were drafted as part of a clinical trial application that received approval from Health Canada. The results of this work are intended to contribute to establishing a regulatory framework for using cyclotron-produced 99mTc in routine clinical practice. © 2015 by the Society of Nuclear Medicine and Molecular Imaging, Inc.
Watt R.,Advanced Cyclotron Systems Inc. |
Gyles W.,Advanced Cyclotron Systems Inc. |
Zyuzin A.,Advanced Cyclotron Systems Inc.
Journal of Radioanalytical and Nuclear Chemistry | Year: 2015
ACSI is designing a new 30 MeV cyclotron based on the TR-24. While minimizing changes from the proven TR-24, including maintaining the same outer dimensions, the energy of the cyclotron will be increased to 30 MeV, which will make it the most compact, non-superconducting, 30 MeV cyclotron design to date. Maximum beam current will match the TR-24 at 1 mA. With the size and footprint of a typical low energy PET cyclotron, this system will offer users a cost effective solution for a diversified facility capable of producing a wide spectrum of PET and SPECT radioisotopes for research and commercial distribution. © 2015, Akadémiai Kiadó, Budapest, Hungary.
Advanced Cyclotron Systems Inc. | Date: 2014-08-19
Isotopes for medical purposes. Laboratory equipment, namely, cyclotrons, for the production, separation, purification, storage and administration of Molybdenum and Technetium isotopes, radionuclides and radiopharmaceuticals, all of the foregoing for use in scientific and medical research and molecular imaging; cyclotron target subsystems comprised of beam lines, shields, particle accelerators, vacuums, and computer operating systems for the production, separation, purification, storage and administration of Molybdenum and Technetium isotopes, radionuclides and radiopharmaceuticals, all of the foregoing for use in scientific and medical research and molecular imaging. Installation of cyclotrons and cyclotron target subsystems comprised of beam lines, shields, particle accelerators, vacuums, and computer operating systems, for the production of Molybdenum and Technetium isotopes, radionuclides and radiopharmaceuticals for use in scientific and medical research and medical diagnostics. Custom manufacture and fitting of cyclotrons. Providing training for the operation and maintenance of cyclotrons to produce and store Molybdenum and Technetium isotopes, radionuclides and radiopharmaceuticals; providing training for the use of Molybdenum and Technetium isotopes, radionuclides and radiopharmaceuticals for scientific and medical research and for medical diagnostics. Designing of cyclotrons and cyclotron target subsystems; laboratory research regarding the application of Technetium isotopes in medical research and medical diagnostics.
Advanced Cyclotron Systems Inc. | Date: 2014-03-14
Isotopes for medical purposes. Laboratory equipment for the production and extraction of radiosotopes, namely, cyclotrons, lead shielded enclosures and automated extraction modules and systems. Installation and maintenance of cyclotrons and cyclotron subsystems for the production of isotopes for use in scientific research and medical diagnostics.