US 5,210,494 AGranted

Sample head for nuclear magnetic resonance whole-body tomography or localized in-vivo nuclear magnetic resonance spectroscopy

AssigneeMax-Planck-Gesellschaft zur Forderung der Wissenschaften e.V.

InventorsHermann Brunner, Karl H. Hausser, Werner Veith

Life of this patent

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Abstract

A sample head (50) for nuclear magnetic resonance whole-body tomography or localized in-vivo nuclear magnetic resonance spectroscopy comprises an RF coil (51) having a plurality of inductive sections in the form of metallic strips (53 to 60) and capacitive sections in the form of gaps (61 to 68) arranged alternately one behind the other in the direction of the RF current (I.sub.1), so that the field lines (72) of the magnetic RF field (H.sub.1) generated by the RF coil (51) extend in parallel to an axis (74) defined by the RF coil (51). The RF coil (51) forms a single unit with an outer jacket (52). The number of inductive and capacitive sections is such as to be just below that limit value above which the distribution of the field lines (71) of the electric RF field (E.sub.1) produced by the said RF coil (51) changes from a first distribution (75), where there is a plane (76) between each inductive section (55) and the said axis (74) in which the strength of the electric RF field (E.sub.1) is equal to zero, to a second distribution where the strength of the said electric RF field (E.sub.1) rises in a substantially rotationally symmetrical pattern around the said axis, and linearly from the said axis toward the said RF coil, and this irrespective of the number of inductive sections present.

Claims24

Dependent claims

Sample head for nuclear magnetic resonance whole-body tomography or localized in-vivo nuclear magnetic resonance spectroscopy, comprising an RF coil (11;

31;
51;
81;
101, 102;
111, 112;
141 to 144;
151, 152;
171) having a plurality (n) of inductive sections in the form of metallic strips (13, 14;
33 to 36;
53 to 60;
83 to 88;
114 to 121;
153 to 160;
172 to 187) and capacitive sections arranged alternately one behind the other in the direction of the RF current (I.sub.1), so that the field lines (20;
44;
72;
104;
125;
145, 146;
162;
191, 192) of the magnetic RF field (H.sub.1) generated by the RF coil (11;
31;
51;
81;
101, 102;
111, 112;
141 to 144;
151, 152;
171) extend in parallel to an axis (21;
45;
74;
126) defined by the RF coil (11;
31;
51;
81;
101, 102;
111, 112;
141 to 144;
151, 152;
171), wherein the said RF coil (31;
51;
81;
101, 102;
111, 112;
141 to 144;
151, 152;
171) forms a single unit with an outer jacket (32;
52;
82;
103;
113) and the number (n) of inductive and capacitive sections is such as to be just below that limit value (n.sub.k) above which the distribution (22;
46;
74) of the field lines (19;
43;
71;
97) of the electric RF field (E.sub.1) produced by the said RF coil (11;
31;
51;
81;
101, 102;
111, 112;
141 to 144;
151, 152;
171) changes from a first distribution (22;
46;
75), where there is a plane (76) between each inductive section (strip 55) and the said axis (74) in which the strength of the electric RF field (E.sub.1) is equal to zero, to a second distribution (98) where the strength of the said electric RF field (E.sub.1) rises in a substantially rotationally symmetrical pattern around the said axis (99), and linearly from the said axis (99) toward the said RF coil (81), and this irrespective of the number (n) of inductive sections present.

63 more elements

A sample head for performing nuclear magnetic resonance measurements on living objects, in particular for whole-body tomography, or localized in-vivo spectroscopy, comprising:

a high-frequency coil structure defining a longitudinal axis and having a predetermined number (n) of inductive elements shaped as metallic strips extending parallel to said axis, and having an equal number (n) of capacitive elements, said inductive elements and said capacitive elements being arranged alternately one behind the other in a circumferential direction about said axis for surrounding a sample space;
an outer shell of electrically conductive material arranged coaxially to said coil structure and surrounding same at a predetermined radial distance (c), said outer shell and said coil structure forming an integral high-frequency unit;
and
means for generating a high-frequency electromagnetic field within said coil structure, said field having magnetic field lines (H.sub.1) extending essentially parallel to said axis within said sample space, and having electric field lines (E.sub.1) and an electric current (I.sub.1) flowing through said inductive elements and said capacitive elements along said circumferential direction;
said predetermined number (n) being selected such as to be just below a threshold value (n.sub.k) below which said electric field lines (E.sub.1) of said electromagnetic field have a first distribution pattern, where there exists within said sample space a plane between each of said inductive elements and said longitudinal axis, in which said electromagnetic field has zero electric field strength, and above which said electric field lines (E.sub.1) of said electromagnetic field have a second distribution pattern of rotational symmetry, where said electric field strength within said sample space increases linearly from said longitudinal axis toward said inductive elements and said capacitive elements, respectively, independently from said number (n) above said threshold value (n.sub.k).

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/663,915Filed 5 Mar 1991
Priority: DE 39220345 Jul 1989
Granted: 11 May 1993
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

G01R 33/34053
Volume type coils, e.g. bird-cage coils; Quadrature bird-cage coils; Circularly polarised coils: solenoid coils; Toroidal coils
G01R 33/34046
Constructional details, e.g. resonators , specially adapted to MR: volume type coils, e.g. bird-cage coils; Quadrature bird-cage coils; Circularly…
G01R 33/34061
Volume type coils, e.g. bird-cage coils; Quadrature bird-cage coils; Circularly polarised coils: helmholtz coils
G01R 33/343
Constructional details, e.g. resonators , specially adapted to MR: of slotted-tube or loop-gap type