Hitachi, Ltd.

Kazuhiro Takeuchi

Shinichi Kojima

Hiroshi Kitaguchi

Kensuke Amemiya

Kazuma Yokoi

Yuuichirou Ueno

Kikuo Umegaki

Norihito Yanagita

Takashi Okazaki

Tsuyoshi Wakuda

Mitsuyoshi Tsuchiya

Hideo Tsukamoto

A radiological imaging apparatus of the present invention comprises an image pickup device and a medical examinee holding device that is provided with a bed. The image pickup device includes a large number of radiation detectors and radiation detector support plates. A large number of radiation detectors are mounted around the circumference of a through-hole and arranged in the axial direction of the through-hole. The radiation detectors are arranged in three layers formed radially with respect to the center of the through-hole and mounted on the lateral surfaces of the radiation detector support plates. Since the radiation detectors are not only arranged in the axial direction and circumferential direction of the through-hole but also arrayed in the radial direction, it is possible to obtain accurate information about a &#x3b3;-ray arrival position in the radial direction of the through-hole (the positional information about a radiation detector from which a &#x3b3;-ray image pickup signal is output). The use of accurate information about &#x3b3;-ray arrival increases the tomogram accuracy. As a result, the present invention enhances the, tomogram accuracy, that is, the PET examination accuracy.

Radiological imaging apparatus

A radiological imaging apparatus of the present invention comprises an image pickup device and a medical examinee holding device that is provided with a bed. The image pickup device includes a large number of radiation detectors and radiation detector support plates. A large number of radiation detectors are mounted around the circumference of a through-hole and arranged in the axial direction of the through-hole. The radiation detectors are arranged in three layers formed radially with respect to the center of the through-hole and mounted on the lateral surfaces of the radiation detector support plates. Since the radiation detectors are not only arranged in the axial direction and circumferential direction of the through-hole but also arrayed in the radial direction, it is possible to obtain accurate information about a &#x3b3;-ray arrival position in the radial direction of the through-hole (the positional information about a radiation detector from which a &#x3b3;-ray image pickup signal is output). The use of accurate information about &#x3b3;-ray arrival increases the tomogram accuracy. As a result, the present invention enhances the tomogram accuracy, that is, the PET examination accuracy.

A radiological imaging apparatus of the present invention comprises an image pickup device and a medical examinee holding device that is provided with a bed. The image pickup device includes a large number of radiation detectors and radiation detector support plates. A large number of radiation detectors are mounted around the circumference of a through-hole and arranged in the axial direction of the through-hole. The radiation detectors are arranged in three layers formed radically with respect to the center of the through-hole and mounted on the lateral surfaces of the radiation detector support plates. Since the radiation detectors are not only arranged in the axial direction and circumferential direction of the through-hole but also arrayed in the radial direction, it is possible to obtain accurate information about a &#x3b3;-ray arrival position in the radial direction of the through-hole (the positional information about a radiation detector from which a &#x3b3;-ray image pickup signal is output). The use of accurate information about &#x3b3;-ray arrival increases the tomogram accuracy. As a result, the present invention enhances the tomogram accuracy, that is, the PET examination accuracy.

A superconducting magnet system with a quench protection circuit includes a superconducting magnet having a plurality of series-connected superconducting coils, a persistent current switch connected in parallel with the superconducting coils, and first and second quench protection circuits connected in parallel with the superconducting coils and the persistent current switch. The first quench protection circuit includes anti-parallel diodes and parallelly connected resistive heaters and shunt resistors, and the resistive heaters and the shunt resistors are each connected in series with the diodes. The second quench protection circuit has a diode and a metal of copper connected with the diode, and a turn-on voltage of the diode in the second quench protection circuit is lower than a turn-on voltage of the diodes in the first quench protection circuit.

Superconducting magnet system with quench protection circuit

A superconducting magnet system includes resistive heaters and bidirectional diodes connected in series with each other installed in a superconducting coil protection circuit, and a diode is installed in a persistent current switch protection circuit.

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Hitachi, Japan

Kazuhiro Takeuchi