Electricity: measuring and testing – Particle precession resonance – Spectrometer components
Reexamination Certificate
2000-01-18
2002-02-19
Williams, Hezron (Department: 2862)
Electricity: measuring and testing
Particle precession resonance
Spectrometer components
C324S322000, C324S319000
Reexamination Certificate
active
06348794
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an RF coil, an MRI apparatus and an NMR signal receiving method, more particularly to an RF coil capable of excluding interaction among coils even in an arrangement in which the coils are arrayed proximately to each other without overlapping adjacent ones of the coils, an NMR apparatus having such an RF coil and an NMR signal receiving method using such an RF coil.
2. Related Art
According to a conventional MRI apparatus, there is used an RF coil integrated with three pieces or more of small coils. According to the conventional RF coil, in order to prevent interaction among the coils, the coils are arranged such that coil faces of adjacent ones of the coils are overlapped-by about 10% thereof.
However, it is inconvenient to restrict to the arrangement in which the coil faces of the adjacent coils are overlapped by about 10%.
SUMMARY OF THE INVENTION
Hence, it is an object of the present invention to provide an RF coil capable of dispensing with mutual interference among coils even in an arrangement in which adjacent coils are arrayed proximately to each other without overlapping adjacent ones of the coils, an MRI apparatus having the RF coil and a method of receiving NMR signals using the RF coil.
According to a first aspect of the present invention, there is provided an RF coil comprising three pieces or more of coils arrayed proximately to each other, coil intermediary connecting capacitors respectively interposed in the respective coils, parallel connection lines for connecting the coil intermediary connecting capacitors of the respective coils in parallel and neutralizing capacitors interposed in the parallel connection lines, wherein by transmitted voltage transmitted from both ends of the coil intermediary connecting capacitor of one of the coils to both ends of the coil intermediary connecting capacitor of other of the coils via the parallel connection lines and the neutralizing capacitors, induced voltage generated across the both ends of the coil intermediary connecting capacitor of other of the coils by the one of the coils via mutual inductance is canceled.
According to the RF coil of the first aspect of the present invention, the voltage generated by the one coil for canceling the voltage induced in the other coil by mutual inductance, is transmitted from the one coil to the other coil via the parallel connection lines and the neutralizing capacitors. Accordingly, the mutual interference among the coils can be dispensed with. Further, there can be arranged so that adjacent coils are arrayed proximately to each other without overlapping the coils.
According to a second aspect of the present invention, there is provided an MRI apparatus featured in comprising the RF coil according to the first aspect of the present invention.
According to the MRI apparatus of the second aspect of the present invention, three pieces or more of coils can be used without being limited to an arrangement in which coil faces of adjacent coils are made to overlap by about 10%.
In this way, according to the RF coil, the MRI apparatus and the NMR signal receiving method of the present invention, mutual interference among coils can be dispensed with in a coil array in which three pieces or more of the coils are used. Therefore, the S/N ratio can be promoted. Further, there can be constituted the arrangement in which adjacent coils are arrayed proximately to each other without overlapping the coils and the degree of freedom can be promoted.
Further objects and advantages of the present invention will be apparent from the following description of the preferred embodiments of the invention as illustrated in the accompanying drawings.
REFERENCES:
patent: 4769605 (1988-09-01), Fox
patent: 5144241 (1992-09-01), Duerr
patent: 5144243 (1992-09-01), Nakabayashi
patent: 5302901 (1994-04-01), Snelton
patent: 5708361 (1998-01-01), Wang
patent: 5973495 (1999-10-01), Mansfield
patent: 0412824 (1991-02-01), None
patent: 9634296 (1996-10-01), None
Ishiguro Takashi
Nabetani Akira
Sato Kenji
GE Yokogawa Medical Systems Limited
Kojima Moonray
Shrivastav Brij B.
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