초록 ▼

Electromagnetic shielding device for nuclear magnetic resonance apparati, having a cavity (5) with at least one or more openings for introducing the body (K) or the part thereof under examination, which cavity (5) is defined by at least one magnet (1) for generating a static field, one or more coils

Electromagnetic shielding device for nuclear magnetic resonance apparati, having a cavity (5) with at least one or more openings for introducing the body (K) or the part thereof under examination, which cavity (5) is defined by at least one magnet (1) for generating a static field, one or more coils for generating a magnetic field gradient (2), one or more coils (3) for generating spin-exciting radio-frequency pulses, and one or more coils (4) for receiving echo signals. The transmitting (3) and receiving coils (4) are contained in an electromagnetic shielding structure (7, 7', 7"), at the openings of the detection cavity (5), whereat the shielding structure may be closed by removable shielding elements (9, 10, 18, 20), electrically connectable thereto. According to the invention, the elements (9, 10, 18, 20) for closing the shield (7, 7', 7") are at least partially provided with openings for the passage of body parts or define openings for the passage of body parts (K), and may be fastened or compressed, with a predetermined force, against said body parts (K), in such a way as to close the opening and generate a safe low-impedance electrical contact between the body (K) and said closing elements (9, 10, 18, 20).

대표청구항 ▼

[ I claim:] [1.] In a nuclear magnetic resonance apparatus including an electromagnetic shielding device, which apparatus has a cavity with an opening for introducing a part of a body under examination, and which cavity is defined by at least one magnet for generating a static field, one or more coi

[ I claim:] [1.] In a nuclear magnetic resonance apparatus including an electromagnetic shielding device, which apparatus has a cavity with an opening for introducing a part of a body under examination, and which cavity is defined by at least one magnet for generating a static field, one or more coils for generating a magnetic field gradient, one or more coils for generating spin-exciting radio-frequency pulses, and one or more coils for receiving the echo signals generated by spin excitation inside the body or the part thereof under examination, said electromagnetic shielding device comprising:an electromagnetic shielding structure made of conductive material, which has an opening at the opening of the cavity,said shielding structure connectable to ground,removable shielding means electrically connectable to the shielding structure at a first end for reducing infiltration of electromagnetic noise from outside to inside of the cavity in an amount being significant for acquisition of echoes and transmission of excitation pulses,the removable shielding means being provided with an opening at a second end for passage of the part of the body, said opening including means for closing said opening against which the part of the body may be pressed with a predetermined force in such a way as to close the opening of the removable shielding means, andthe removable shielding means including means for generating a safe low-impedance electrical contact between the part of the body and said removable shielding means and the shielding structure.