Superconducting magnet apparatus and magnetic resonance imaging apparatus using the same

Abstract

An MRI apparatus is characterized in that magnet members for compensating the magnetic field are disposed to a thermal shield system of the superconducting apparatus. It is another feature of the present invention that the magnet members for compensating the magnetic field are disposed at positions where temperature change in the vacuum chamber is not transferred to the interior of the vacuum chamber.

Description

CLAIM OF PRIORITY [0001] The present application claims priority from Japanese application No. 2003-386052, filed on Nov. 17, 2003, the content of which is hereby incorporated by reference into this application. DESCRIPTION OF THE INVENTION [0002] 1. Technical Field [0003] The present invention relates to a superconducting magnet apparatus and a magnetic resonance imaging apparatus using the same (hereinafter referred to as MRI apparatus) and more particularly to a superconducting magnet apparatus suitable for an open type MRI apparatus that does not give feeling of blockade to an examinee and to an MRI apparatus that utilizes the magnet apparatus. [0004] 2. Background of the Invention [0005] In the conventional MRI apparatuses, magnets are disposed at positions where the superconducting magnet apparatus of the MRI apparatuses have the normal temperature or room temperature. [0006] In another example of superconducting magnets of the MRI apparatus, a ferromagnetic magnet which is di...

AI Technical Summary

Benefits of technology

[0019] The present invention aims at solving the above-described problems, and its object is to provide a superconducting magnet apparatus and an MRI apparatus characterized in that the change of homogeneity of a generated magnetic field is minimized and even if the magnet members for compensating or correcting the magnetic field are utilized, an increase of the weight of the superconducting magnet apparatus is suppressed.

[0023] According to the superconducting magnet apparatus, since it is possible to make minimum the magnetic field change due to room temperature change and vibration even when the magnet members for compensating the magnetic field are used, the MRI apparatus using the superconducting magnet with a high performance can be provided.

Problems solved by technology

However, there are following problems if the magnets are disposed at the positions of the normal temperature of the superconducting magnet apparatus.

Although disposing the magnet members in the vacuum containers with which ultra low temperature helium is filled may dissolve the above-mentioned problems, there is the following problem on the other.

Accordingly, since the effect of the magnet members on the center of the magnetic field decreases in accordance with the distance, the volume of the magnet members becomes larger resulting in an increase of the weight of the magnet members; in some cases, the compensation or correction of the magnetic field becomes difficult.

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