US5207222A — Method and apparatus for measuring temperature of…

Claim 1

Independent Claim 137 words

A method of measuring a temperature of a subject comprising: a step of applying a static field to said subject; a step of applying a first field to said subject so as to excite a nuclear spin of a portion of said subject to be measured; a step of applying a second field to said subject so as to generate NMR signals from said portion to be measured; a step of applying a third field to said subject so as to change coherence of said nuclear spin in accordance with a temperature distribution of said portion to be measured; and a step of reading said NMR signals and obtaining the temperature state of said portion to be measured from the change of intensity of said NMR signals corresponding to the change of coherence of said nuclear spin.

Claim 2

Independent Claim 137 words

A method of measuring a temperature of a subject comprising: a step of applying a static field to said subject; a step of applying a first field to said subject so as to excite a nuclear spin of a portion of said subject to be measured; a step of applying a second field to said subject so as to generate NMR signals from said portion to be measured; a step of applying a third field to said subject so as to change coherence of said nuclear spin in accordance with a temperature distribution of said portion to be measured; and a step of reading said NMR signals and obtaining the temperature state of said portion to be measured from the change of intensity of said NMR signals corresponding to the change of coherence of said nuclear spin.

Claim 3

Dependent Claim 47 words

A method of measuring a temperature of a subject according to claim 1, further comprising a step of associating multi-dimensionally the changes of intensity of said NMR signals by utilizing the frequency of said NMR signals and obtaining the temperature distribution of said portion to be measured.

Claim 4

Dependent Claim 48 words

A method of measuring a temperature of a subject according to claim 1, wherein said step of obtaining the temperature distribution includes utilizing a functional relation between said coherence and the intensity of said NMR signals containing a transverse relaxation time of said nuclear spin as a parameter.

Claim 5

Dependent Claim 53 words

A method of measuring a temperature of a subject according to claim 3, which further includes a step of obtaining a transverse relaxation time of said spin of said portion to be measured, and utilizing the obtained transverse relaxation time in the relation between said coherence and the intensity of said NMR signals.

Claim 6

Dependent Claim 44 words

A method of measuring a temperature of a subject according to claim 1, further comprising the step of heating said portion to be measured so that the temperature of said portion to be measured is higher than that of other portions of said subject.

Claim 7

Dependent Claim 15 words

A method according to claim 1, wherein said second field is a radio frequency field.

Claim 8

Independent Claim 216 words

A method of measuring a temperature distribution of a subject comprising: (a) a step of applying a static field to said subject; (b) a step of applying a radio frequency field for inducing magnetic resonance to said subject; (c) a step of applying a gradient field in a Z-axis direction of said subject in order to select a portion to be measured; (d) a step of applying a gradient field for phase encoding in a Y-axis direction of said subject; (e) a step of applying a gradient field for reading in an X-axis direction of said subject; (f) a step of applying a field for temperature measurement to said subject so as to change coherence o said nuclear spin in accordance with the temperature distribution of said portion of said subject to be measured; (g) a step of executing said steps (b) through (f) while changing at least said gradient field for phase encoding, and emitting a large number of NMR signals from said portion to be measured; and (h) a step of reading said NMR signals and obtaining the temperature distribution of said portion to be measured from the intensity of said NMR signals corresponding to the change of coherence of said nuclear spin and the frequency corresponding to the position of said nuclear spin.

Claim 9

Independent Claim 216 words

A method of measuring a temperature distribution of a subject comprising: (a) a step of applying a static field to said subject; (b) a step of applying a radio frequency field for inducing magnetic resonance to said subject; (c) a step of applying a gradient field in a Z-axis direction of said subject in order to select a portion to be measured; (d) a step of applying a gradient field for phase encoding in a Y-axis direction of said subject; (e) a step of applying a gradient field for reading in an X-axis direction of said subject; (f) a step of applying a field for temperature measurement to said subject so as to change coherence o said nuclear spin in accordance with the temperature distribution of said portion of said subject to be measured; (g) a step of executing said steps (b) through (f) while changing at least said gradient field for phase encoding, and emitting a large number of NMR signals from said portion to be measured; and (h) a step of reading said NMR signals and obtaining the temperature distribution of said portion to be measured from the intensity of said NMR signals corresponding to the change of coherence of said nuclear spin and the frequency corresponding to the position of said nuclear spin.

Claim 10

Dependent Claim 69 words

A method of measuring a temperature distribution of a subject according to claim 7, wherein said field for temperature measurement in said step (f) comprises a dephase pulse and a rephase pulse that are applied in the X-direction of said subject and the change of coherence of said nuclear spin is expressed as the change of amplitude of said NMR signals after the application of said pair of pulses.

Claim 11

Dependent Claim 33 words

A method of measuring a temperature distribution of a subject according to claim 8, wherein said dephase pulse and said rephase pulse are generated by means for generating said gradient field for reading.

Claim 12

Dependent Claim 89 words

A method of measuring a temperature distribution of a subject according to claim 9, wherein said step (f) includes utilizing the following relation between said coherence of said nuclear spin and the intensity of said NMR signals: S=S.sub.o exp (-TE/T.sub.2)·exp {-γ.sup.2 Gxi.sup.2 Dδ2 (Δ-δ/3)} where S: signal intensity S o : reference signal intensity TE: echo time T 2 : transverse relaxation time γ: gyromagnetic ratio Gxi: magnitude of dephase/rephase pulse D: diffusion coefficient, i.e. coefficient expression of coherence δ: dephase/rephase pulse width Δ: time interval of dephase/rephase pulse.

Claim 13

Dependent Claim 18 words

A method according to claim 7, wherein said radio frequency field is generated by a RF pulse generator.

Claim 14

Independent Claim 222 words

A method of measuring a temperature of a subject comprising: (a) a step of applying a static field to said subject; (b) a step of applying a first field to said subject so as to excite a nuclear spin at a portion of said subject to be measured; (c) a step of applying a second field to said subject so as to generate NMR signals from said portion to be measured; (d) a step of applying a third field to said subject so as to change coherence of said nuclear spin in accordance with a temperature distribution of said portion to be measured; (e) a step of reading said NMR signals and obtaining the temperature state of said portion to be measured from the change of intensity of said NMR signals corresponding to the change of coherence of said nuclear spin; (f) a step of executing said steps (b) through (e) for a second portion of said subject whose temperature is known and serves as a reference portion, and obtaining a relation between the change of intensity of said NMR signals and the temperature; and (g) a step of comparing the change of intensity of said NMR signals obtained from said portion to be measured with said relation, and expressing the temperature of said portion to be measured in an absolute unit.

Claim 15

Independent Claim 222 words

A method of measuring a temperature of a subject comprising: (a) a step of applying a static field to said subject; (b) a step of applying a first field to said subject so as to excite a nuclear spin at a portion of said subject to be measured; (c) a step of applying a second field to said subject so as to generate NMR signals from said portion to be measured; (d) a step of applying a third field to said subject so as to change coherence of said nuclear spin in accordance with a temperature distribution of said portion to be measured; (e) a step of reading said NMR signals and obtaining the temperature state of said portion to be measured from the change of intensity of said NMR signals corresponding to the change of coherence of said nuclear spin; (f) a step of executing said steps (b) through (e) for a second portion of said subject whose temperature is known and serves as a reference portion, and obtaining a relation between the change of intensity of said NMR signals and the temperature; and (g) a step of comparing the change of intensity of said NMR signals obtained from said portion to be measured with said relation, and expressing the temperature of said portion to be measured in an absolute unit.

Claim 16

Independent Claim 209 words

A method of measuring a perfusion rate of a body fluid of a subject, comprising: a step of obtaining in advance a relation between a temperature state of a portion of said subject to be measured, for which measurement of the perfusion rate of the body liquid is required, and the perfusion rate of the body fluid; a step of applying a static field to said subject; a step of applying a first field to said subject so as to excite a nuclear spin at the portion of said subject to be measured; a step of applying a second field to said subject so as to generate NMR signals from said portion to be measured; a step of applying a third field to said subject so as to change coherence of said nuclear spin in accordance with a temperature distribution of said portion to be measured; a step of reading said NMR signals and obtaining the temperature state of said portion to be measured from the change of intensity of said NMR signals corresponding to the change of coherence of said nuclear spin; and a step of comparing said temperature state with said relation and obtaining the perfusion rate of the body fluid of said portion to be measured.

Claim 17

Independent Claim 209 words

A method of measuring a perfusion rate of a body fluid of a subject, comprising: a step of obtaining in advance a relation between a temperature state of a portion of said subject to be measured, for which measurement of the perfusion rate of the body liquid is required, and the perfusion rate of the body fluid; a step of applying a static field to said subject; a step of applying a first field to said subject so as to excite a nuclear spin at the portion of said subject to be measured; a step of applying a second field to said subject so as to generate NMR signals from said portion to be measured; a step of applying a third field to said subject so as to change coherence of said nuclear spin in accordance with a temperature distribution of said portion to be measured; a step of reading said NMR signals and obtaining the temperature state of said portion to be measured from the change of intensity of said NMR signals corresponding to the change of coherence of said nuclear spin; and a step of comparing said temperature state with said relation and obtaining the perfusion rate of the body fluid of said portion to be measured.

Claim 18

Dependent Claim 12 words

A method according to claim 13, wherein the body fluid is blood.

Claim 19

Independent Claim 125 words

An apparatus for measuring a subject, comprising: means for applying a static field to said subject; means for applying a first field to said subject so as to excite a nuclear spin at a portion of said subject to be measured; means for applying a second field to said subject so as to generate NMR signals from said portion to be measured; means for applying a third field to said subject so as to change coherence of said nuclear spin in accordance with a temperature distribution of said portion to be measured; and means for obtaining the temperature state of said portion to be measured from the change of intensity of said NMR signals in accordance with the change of coherence of said nuclear spin.

Claim 20

Independent Claim 125 words

An apparatus for measuring a subject, comprising: means for applying a static field to said subject; means for applying a first field to said subject so as to excite a nuclear spin at a portion of said subject to be measured; means for applying a second field to said subject so as to generate NMR signals from said portion to be measured; means for applying a third field to said subject so as to change coherence of said nuclear spin in accordance with a temperature distribution of said portion to be measured; and means for obtaining the temperature state of said portion to be measured from the change of intensity of said NMR signals in accordance with the change of coherence of said nuclear spin.

Claim 21

Independent Claim 206 words

An apparatus for measuring a temperature distribution of a subject, comprising: (a) means for applying a static field to said subject; (b) means for applying a radio frequency field for inducing magnetic resonance to said subject; (c) means for applying a gradient field for selecting a portion to be measured in a Z-axis direction of said subject; (d) means for applying a gradient field for phase encoding to a Y-axis of said subject; (e) means for applying a gradient field for reading in an X-axis direction of said subject; (f) means for applying a field for temperature measurement to said subject so as to change coherence of a nuclear spin in accordance with a temperature distribution of said portion to be measured; (g) means for executing the operations of said means (b) through (f) while changing at least said gradient field for phase encoding, and emitting a large number of NMR signals from said portion to be measured; and (h) means for reading said NMR signals and obtaining the temperature distribution of said portion to be measured from the intensity of said NMR signals corresponding to the change of coherence of said nuclear spin and from its frequency corresponding to the position of said nuclear spin.

Claim 22

Independent Claim 206 words

An apparatus for measuring a temperature distribution of a subject, comprising: (a) means for applying a static field to said subject; (b) means for applying a radio frequency field for inducing magnetic resonance to said subject; (c) means for applying a gradient field for selecting a portion to be measured in a Z-axis direction of said subject; (d) means for applying a gradient field for phase encoding to a Y-axis of said subject; (e) means for applying a gradient field for reading in an X-axis direction of said subject; (f) means for applying a field for temperature measurement to said subject so as to change coherence of a nuclear spin in accordance with a temperature distribution of said portion to be measured; (g) means for executing the operations of said means (b) through (f) while changing at least said gradient field for phase encoding, and emitting a large number of NMR signals from said portion to be measured; and (h) means for reading said NMR signals and obtaining the temperature distribution of said portion to be measured from the intensity of said NMR signals corresponding to the change of coherence of said nuclear spin and from its frequency corresponding to the position of said nuclear spin.

Claim 23

Independent Claim 216 words

An apparatus for measuring a temperature of a subject, comprising, (a) means for applying a static field to said subject; (b) means for applying a first field to said subject so as to excite a nuclear spin at a portion of said subject to be measured; (c) means for applying a second field to said subject so as to generate NMR signals from said portion to be measured; (d) means for applying a third field to said subject so as to change coherence of said nuclear spin in accordance with a temperature distribution of said portion to be measured; (e) means for reading said NMR signals, and acquiring the temperature state of said portion to be measured from the change of intensity of said NMR signals corresponding to the change of coherence of said nuclear spin; (f) means for executing the operations of said means (b) through (f) for a second portion of said subject whose temperature is known and serves as a reference portion, and acquiring a relation between the intensity change of said NMR signal and the temperature; and (g) means for comparing the intensity change of said NMR signal obtained from said portion to be measured with said relation, and expressing the temperature of said portion to be measured in an absolute unit.

Claim 24

Independent Claim 216 words

An apparatus for measuring a temperature of a subject, comprising, (a) means for applying a static field to said subject; (b) means for applying a first field to said subject so as to excite a nuclear spin at a portion of said subject to be measured; (c) means for applying a second field to said subject so as to generate NMR signals from said portion to be measured; (d) means for applying a third field to said subject so as to change coherence of said nuclear spin in accordance with a temperature distribution of said portion to be measured; (e) means for reading said NMR signals, and acquiring the temperature state of said portion to be measured from the change of intensity of said NMR signals corresponding to the change of coherence of said nuclear spin; (f) means for executing the operations of said means (b) through (f) for a second portion of said subject whose temperature is known and serves as a reference portion, and acquiring a relation between the intensity change of said NMR signal and the temperature; and (g) means for comparing the intensity change of said NMR signal obtained from said portion to be measured with said relation, and expressing the temperature of said portion to be measured in an absolute unit.

Claim 25

Dependent Claim 19 words

An apparatus according to claim 17, wherein said means for applying a second field applies a radio frequency field.

Claim 26

Independent Claim 201 words

An apparatus for measuring a perfusion rate of a body fluid of a subject, comprising: means for obtaining in advance a relation between a temperature state of a portion of a subject to be measured, for which the perfusion rate of the body fluid must be measured, and the perfusion rate of said body fluid; means for applying a static field to said subject; means for applying a first field to said subject so as to excite a nuclear spin at said portion of said subject to be measured; means for applying a second field to said subject so as to generate NMR signals from said portion to be measured; means for applying a third field to said subject so as to change coherence of said nuclear spin in accordance with a temperature distribution of said portion to be measured; means for reading said NMR signals and obtaining the temperature state of said portion to be measured from the change of intensity of said NMR signals corresponding to the change of coherence of said nuclear spin; and means for acquiring the perfusion rate of the body fluid of said portion to be measured by comparing said temperature state with said relation.

Claim 27

Independent Claim 201 words

An apparatus for measuring a perfusion rate of a body fluid of a subject, comprising: means for obtaining in advance a relation between a temperature state of a portion of a subject to be measured, for which the perfusion rate of the body fluid must be measured, and the perfusion rate of said body fluid; means for applying a static field to said subject; means for applying a first field to said subject so as to excite a nuclear spin at said portion of said subject to be measured; means for applying a second field to said subject so as to generate NMR signals from said portion to be measured; means for applying a third field to said subject so as to change coherence of said nuclear spin in accordance with a temperature distribution of said portion to be measured; means for reading said NMR signals and obtaining the temperature state of said portion to be measured from the change of intensity of said NMR signals corresponding to the change of coherence of said nuclear spin; and means for acquiring the perfusion rate of the body fluid of said portion to be measured by comparing said temperature state with said relation.

Claim 28

Dependent Claim 25 words

An apparatus according to claim 19, wherein the body fluid is blood and said means for applying the second field applies a radio frequency field.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1996-05-03	1996-11-02	1997-05-04	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2000-05-03	2000-11-02	2001-05-04	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2004-05-03	2004-11-02	2005-05-04	$7700.00	Window Closed / Lapsed

Method and apparatus for measuring temperature of subject

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