Yasuki Nagai

Generation of radioisotopes with accelerator neutrons by deuterons

A new system proposed for the generation of radioisotopes with accelerator neutrons by deuterons (GRAND) is described by mainly discussing the production of 99Mo used for nuclear medicine diagnosis. A prototype facility of this system consists of a cyclotron to produce intense accelerator neutrons from the natC(\(d\),\(n\)) reaction with 40 MeV 2 mA deuteron beams, and a sublimation system to separate 99mTc from an irradiated 100MoO3 sample. About 8.1 TBq/week of 99Mo is produced by repeating irradiation on an enriched 100Mo sample (251 g) with accelerator neutrons for two days three times. It meets about 10% of the 99Mo demand in Japan. The characteristic feature of the system lies in its capability to reliably produce a wide variety of high-quality, carrier-free, carrier-added radioisotopes with a minimum level of radioactive waste without using uranium. The system is compact in size, and easy to operate; therefore it could be used worldwide to produce radioisotopes for medical, research, and industrial...

New Production Routes for Medical Isotopes 64Cu and 67Cu Using Accelerator Neutrons

We have measured the activation cross sections producing 64Cu and 67Cu, promising medical radioisotopes for molecular imaging and radioimmunotherapy, by bombarding a natural zinc sample with 14 MeV...

Successful labeling of 99mTc-MDP using 99mTc separated from 99Mo produced by 100Mo(n,2n)99Mo

We have for the first time succeeded in separating 99m Tc from a MoO 3 sample irradiated with accelerator neutrons free from any radioactive impurities and in formulating 99m Tc-methylene diphosphonate ( 99m Tc-MDP). 99 Mo, the mother nuclide of 99m Tc, was produced by the 100 Mo( n ,2 n ) 99 Mo reaction using about 14 MeV neutrons provided by the 3 H( d , n ) 4 He reaction at the Fusion Neutronics Source of Japan Atomic Energy Agency. The 99m Tc was separated from 99 Mo by sublimation and its radionuclide purity was confirmed to be higher than 99.99% by γ-spectroscopy. The labeling efficiency of 99m Tc-MDP was shown to be higher than 99% by thin-layer chromatography. These values exceed the United States Pharmacopeia requirements for a fission product, 99 Mo. Consequently, a 99m Tc radiopharmaceutical preparation formed by using the mentioned 99 Mo can be a promising substitute for the fission product 99 Mo, which is currently produced using a highly enriched uranium target in aging research reactors. A ...

First Measurement of the Radionuclide Purity of the Therapeutic Isotope 67Cu Produced by 68Zn(n,x) Reaction Using natC(d,n) Neutrons

We have for the first time studied the radionuclide purity of the therapeutic isotope 67Cu produced by the 68Zn(n,x)67Cu reaction. The neutrons were obtained by the natC(d,n) reaction using 40 MeV ...

Experimental Study of Nuclear Astrophysics with Photon Beams

Information on the photonuclear reactions in the energy region below the E1 giant resonances is vital for understanding astrophysical processes relevant to nucleosynthesis. Several topics from recent experimental studies of the photonuclear reactions with a high‐quality monochromatic γ‐ray beam will be presented.

Recommended nuclear data for medical radioisotope production: diagnostic gamma emitters

An extensive series of evaluations have been performed as part of an IAEA coordinated research project to study a set of nuclear reactions that produce the diagnostic gamma-ray emitting radionuclides 51Cr, 99mTc, 111In, 123I and 201Tl. Recommended cross-section data in the form of excitation functions have been derived, along with quantifications of their uncertainties. These evaluations involved the compilation of all previously published values and newly measured experimental data, followed by critical assessments and selection of those experimental datasets and accompanying uncertainties judged to be fully valid and statistically consistent for model-independent least-squares fitting by means of Padé approximations. Integral yields as a function of the energy were also calculated on the basis of the recommended cross sections deduced from these various fits. All evaluated numerical results and their corresponding uncertainties are available online at www-nds.iaea.org/medical/gamma_emitters.html and also on the medical portal of the International Atomic Energy Agency/Nuclear Data Section (IAEA-NDS) www-nds.iaea.org/medportal/.

SU‐C‐144‐01: Imaging Study of An Electron‐Tracking Compton Camera for Nuclear Medicine

PURPOSE Conventional gamma-ray detector, PET and SPECT, have the limitation of energy. These limitations are major problems of studying for a new medical imaging. Therefore, we have developed the new imaging detector which is an electron-tracking Compton camera (ETCC). We show results of the update ETCC system and show the imaging Result of 95m-Tc which is one of the targets for new imaging reagents. METHODS The ETCC has a wide energy dynamic range and wide field of view. Also the ETCC can detect recoil-electron tracks which are generated from Compton scattering. We have developed the new ETCC system which have been modified the logic of catching the electron tracks and have better performance compared with old system. The 99m-Tc is the most important radioisotopes which are used in nuclear medicine. However, the lifetime of the 99m-Tc is 6 hours, it may not be possible to use imaging reagent for using antibody reaction because of accumulation time. The technetium, however, have many isotopes and many energy peaks. If we can reconstruct gamma rays which have various energy peaks, imaging technology for nuclear medicine will progress. The 95m-Tc (204, 582, 835 keV ) is one of the targets for a new imaging reagent. In this presentation, we show the new ETCC system performance and 95m-Tc imaging results. RESULTS ETCC achieved a wide energy dynamic range (200-1300keV) and wide field of view. We could catch the recoil electron tracks clearly using new ETCC system, and we succeeded in imaging of the 95m-Tc. CONCLUSION We have developed the ETCC for new medical imaging device and succeeded in imaging of the 95m-Tc. We started to develop the ETCC which can image the mouse within 30 min. Thus, this detector has the possibility of new medical imaging.

Study of 12C(γ, 2α)4He with NewSUBARU laser Compton scattered gamma‐ray beam

The 16O(γ, 2α)4He reaction cross section was measured in the γ‐ray energy range from 16 MeV up to 39 MeV using an active target method and a quasi‐monochromatic γ‐ray beam provided at the Laboratory of Advanced Science and Technology for Industry (LASTI) of the University of Hyogo. The cross section is found to be rather small in the energy region corresponding to the 2+ and 4+ excited states of the intermediate 8Be nucleus, while it becomes large above the energy corresponding to the 8Be 1− state, being in contrast to the latest result reported by Afanas’ev and Khodyachikh. The present result suggests the cross sections are dominated by the contributions of the 1− states in 12C which are excited with the E1 transition.

Measurement of E1 and E2 cross sections of 12C(α,γ)16O using pulsed α beams

We have measured the γ‐ray angular distribution of the 12C(α,γ)16O reaction at a center‐of‐mass energy of Ecm = 1.6 MeV and Ecm = 1.4 MeV. In this experiment, we used high efficiency anti‐Compton NaI(Tl) spectrometers to detect a γ‐ray from the reaction with a large S/N ratio, intense pulsed α beams to discriminate true events from neutron induced background by using a time‐of‐flight (TOF) method, and the monitoring system of target thickness. We could pick up true events from the reaction free from intense neutron background with high statistics.

E1 and E2 cross sections of the 12C(α,γ)16O reaction at Ecm∼1.4 Mev using pulsed α beams

We have installed a new system to measure the γ‐ray angular distribution of the 12 C (α,γ) 16 O reaction at the 3.2 MV Pelletron accelerator laboratory at Tokyo Institute of Technology to accurately determine the E1 and E2 cross sections. In this experiment, we used high efficiency anti‐Compton NaI(T1) spectrometers to detect a γ‐ray from the reaction with a large S/N ratio, intense pulsed α beams to discriminate true events from neutron induced background with a time‐of‐flight (TOF) method, and the monitoring system of target thickness. We succeeded in removing a background due to neutrons and could clearly detect the γ‐ray from the 12 C (α,γ) l6 O reaction with high statistics.We have measured the {gamma}-ray angular distribution of the {sup 12}C({alpha}, {gamma}){sup 16}O reaction at the 3.2 MV Pelletron accelerator laboratory at Tokyo Institute of Technology to accurately determine the E1 and E2 cross sections. In this experiment, we used high efficiency anti-Compton NaI(Tl) spectrometers to detect a {gamma}-ray from the reaction with a large S/N ratio, intense pulsed {alpha}-beams to discriminate true events from background events due to neutrons from {sup 13}C({alpha}, n){sup 16}O reaction with a time-of-flight method, and the monitoring system of target thickness. We succeeded in removing a background events due to neutrons and clearly detected the {gamma}-ray from the {sup 12}C({alpha}, {gamma}){sup 16}O reaction with high statistics.