Production of positron-emitting radionuclide yttrium-86 with a computer-aided design target for positron emission tomography.

Yttrium-86 (86Y, t1/2 = 14.7 h, 33% ß+) is a nonstandard medical nuclide with a longer half-life than other standard nuclides such as gallium-68 for radiolabelling for PET (positron emission computed tomography) imaging. 86Y is compatible with DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) and can be used to evaluate DOTA-chelated radiopharmaceuticals with long clearance half-lives, particularly therapeutic radiopharmaceuticals in several days. 86Y can be produced through 86Sr(p, n)86Y reaction, in which 86Sr-enriched SrCO3 powder is bombarded with low-energy protons. To handle the SrCO3 powder, a powder target for 86Y production in 14.6 MeV proton cyclotron was designed while maximizing yield, reliability and efficiency. To that end, the target's primary design parameters were traversed, simulated and optimized using computer algorithms to obtain advantageous parameter combinations. In this way, 86Y was produced on the powder target with high yield and successfully isolated with high purity (>97%) by solid-phase extraction via DGA resin for high-quality PET imaging and drug screening.

Ion source and injection line for high intensity medical cyclotron.

A 14 MeV high intensity compact cyclotron, CYCIAE-14, was built at China Institute of Atomic Energy (CIAE). An injection system based on the external H- ion source was used on CYCIAE-14 so as to provide high intensity beam, while most positron emission tomography cyclotrons adopt internal ion source. A beam intensity of 100 µA/14 MeV was extracted from the cyclotron with a small multi-cusp H- ion source (CIAE-CH-I type) and a short injection line, which the H- ion source of 3 mA/25 keV H- beam with emittance of 0.3π mm mrad and the injection line of with only 1.2 m from the extraction of ion source to the medial plane of the cyclotron. To increase the extracted beam intensity of the cyclotron, a new ion source (CIAE-CH-II type) of 9.1 mA was used, with maximum of 500 µA was achieved from the cyclotron. The design and test results of the ion source and injection line optimized for high intensity acceleration will be given in this paper.

Experimental development on the 18 mA, H- multi-cusp ion source at China Institute of Atomic Energy.

The ion source is one of the key devices for the high-intensity cyclotron, which exerts influence on the beam intensity and applications of the machine. The H(-) multi-cusp ion source developed at China Institute of Atomic Energy has been used to perform experimental study on beam intensity and emittance versus the bias voltage, arc power, lens voltage, and pressure of the ion source. Up to now, 18 mA H(-) ion beam with emittance of 0.93 πmm mrad (four times RMS normalized emittance) was obtained from this ion source through the in-depth study and optimization on some essential factors affecting the beam intensity and quality. The paper will present the experimental study on the ion source as well as the beam test results.

Development of a compact filament-discharge multi-cusp H- ion source.

A 14 MeV medical cyclotron with the external ion source has been designed and is being constructed at China Institute of Atomic Energy. The H(-) ion will be accelerated by this machine and the proton beam will be extracted by carbon strippers in dual opposite direction. The compact multi-cusp H(-) ion source has been developed for the cyclotron. The 79.5 mm long ion source is 48 mm in diameter, which is consisting of a special shape filament, ten columns of permanent magnets providing a multi-cusp field, and a three-electrode extraction system. So far, the 3 mA∕25 keV H(-) beam with an emittance of 0.3 π mm mrad has been obtained from the ion source. The paper gives the design details and the beam test results. Further experimental study is under way and an extracted beam of 5 mA is expected.

Design of a compact, permanent magnet electron cyclotron resonance ion source for proton and H2(+) beam production.

A 2.45 GHz microwave ion source was developed at China Institute of Atomic Energy (CIAE) for proton beam production of over 60 mA [B.-Q. Cui, Y.-W. Bao, L.-Q. Li, W.-S. Jiang, and R.-W. Wang, Proceedings of the High Current Electron Cyclotron Resonance (ECR) Ion Source for Proton Accelerator, APAC-2001, 2001 (unpublished)]. For various proton beam applications, another 2.45 GHz microwave ion source with a compact structure is designed and will be built at CIAE as well for high current proton beam production. It is also considered to be used for the test of H(2)(+) beam, which could be injected into the central region model cyclotron at CIAE, and accelerated to 5 MeV before extraction by stripping. The required ECR magnetic field is supplied by all the permanent magnets rather than electrical solenoids and six poles. The magnetic field distribution provided by this permanent magnets configuration is a large and uniformly volume of ECR zone, with central magnetic field of a magnitude of approximately 875 Gs [T. Taylor and J. S. C. Wills, Nucl. Instrum. Methods Phys. Res. A 309, 37 (1991)]. The field adjustment at the extraction end can be implemented by moving the position of the magnet blocks. The results of plasma, coupling with 2.45 GHz microwave in the ECR zone inside the ion source are simulated by particle-in-cell code to optimize the density by adjusting the magnetic field distribution. The design configuration of the ion source will be summarized in the paper.

Experimental study for 15-20 mA dc H- multicusp source.

Recently, a new H- source and test stand was developed at CIAE. The design of this new source is based on the experience on our previous 10-15 mA H(-) ion source and the source at TRIUMF. Major efforts include the study of the virtual filter magnetic field, confining magnetic field, filament shape and location, the vacuum improvement on the extracting area, the extraction optics, new control and interlock system of the power supplies. More than 15 mA of H-beam was obtained for 36 h with stability of +/-0.5%. The normalized emittance of 0.48pi mm mrad (4 rms normalized emittance) were measured with approximately 8 mA dc beam. Further experimental studies are proceeding in an effort to reach 20 mA with reasonable emittance at this moment. More study plans are conducted, e.g., building a longer source body and using cesium injection to get better emittance, which will be presented as a separate paper at this conference.

Emittance improvement efforts on the 15-20 mA dc H- multicusp source.

A 15 mA beam from the 15-20 mA dc H(-) multicusp source has been obtained at China Institute of Atomic Energy. In order to improve the emittance of extracted beam from this new multicusp source, some measures have been taken, i.e., increasing the length of the ion source body, improving the vacuum in the extraction area, injecting cesium vapor into the ion source, etc. The hardware, including the lengthened source body, the improved back cover and cesium heating system, and the extraction vacuum box, will be described. Initial results for these efforts aimed at emittance improvement will also be given in the paper.

Matching from H(-) multicusp source to central region of a 100 MeV compact cyclotron for high current injection.

The way of matching the beam from an external ion source to the central region of the cyclotron CYCIAE-100 is presented in this article. The transverse acceptances of the central region were calculated, which provided the matching ellipse parameter requirements to the injection transport optics design. The optics of the injection line was simulated using TRANSOPTR, which allowed space charge effect calculation, and neutralization was taken into account.

[Membrane lipid peroxidation and hypersensitive reaction induced by a glycoprotein elicitor from Magnaporthe grisea in rice leaves].

With a series of four near-isogenic lines (NIL) of rice, studies were carried out in the interaction between rice and a specific glycoprotein elicitor from Magnaporthe grisea. After treatment with the elicitor, O(-.)(2) generation rate increased more remarkably on the leaves of incompatible interaction of rice, than compatible interaction of rice. Change in SOD activity and CAT activity was similar in leaves of rice with different resistance after inoculation with the elicitor. On the contrary, POD activity was positive relative to rice resistance. And changes in LOX activity were increased more remarkably and rapidly on the leaves of incompatibly interacting rice. These changes led to lipid peroxidation in the leaves of incompatibly interacting rice. Relative conductance rate and MDA content were also increased more remarkably and rapidly in leaves of incompatibly interacting rice. Our results also showed that elicitor could induce hypersensitive reaction (HR reaction) in leaves of completely or highly incompatible interacting rice, but not in the two NIL rice varieties (one with moderately incompatible interactions and another with compatible ones). The results suggest that lipid peroxidation and HR reaction in rice leaves induced by the elicitor may play an important role in the resistance of rice seedlings.