Abstract: There is disclosed a controlling method of a nuclear magnetic resonance apparatus in which a static magnetic field is generated by a high-temperature superconductor 20 positioned in a vacuum insulating container 22. The method comprises: a magnetizing step (A) for cooling the high-temperature superconductor at a magnetization low temperature sufficiently lower than a superconductor transition temperature, and magnetizing the high-temperature superconductor with the magnetic field; a magnetic flux setting step (B) for raising the temperature of the high-temperature superconductor at a magnetic flux setting temperature higher than the magnetization low temperature and lower than the superconductor transition temperature and setting a predetermined magnetic flux density; and an operation controlling step (C) for controlling the high-temperature superconductor in an operation temperature range lower than the magnetic flux setting temperature.

Abstract: There is disclosed an NMR (nuclear magnetic resonance) probe having a support that produces no NMR background signal, has heat resistance, does not distort homogeneous static magnetic field, has a low dielectric loss, and is easy to machine. The NMR probe has a sample bobbin on which a detector coil is mounted, as well as the support described above. The support holds the sample bobbin. The support is plated with a metal to prevent generation of NMR background signals. The support has a bushing equipped with a hole having a diameter substantially equal to that of an extraction line extending from the detector coil. The hole passes the extraction line. The bushing is made of an insulative material of a low magnetic susceptibility. Thus, leakage of air from the hole is prevented. At the same time, the support and the extraction line are electrically insulated from each other.

Abstract: An MRI-use magnetic field generator structured such that there is no loss of magnetic field uniformity, temperature fluctuation is reduced and thermal efficiency enhanced, and the temperature of the permanent magnets can be controlled to high precision. With this invention, temperature control heaters are embedded in the base yokes of magnetic path formation members, and as a result of this structure, when the temperature control heaters are heated by a temperature regulator according to the temperature detected by a temperature sensor, the permanent magnets disposed in the vicinity of the base yokes are heated efficiently, so control follow-up is excellent. Furthermore, because the temperature control heaters are embedded inside the base yokes, and the heat generated by the heaters is conducted through the base yokes and reaches the permanent magnets directly, the heat is not diffused to the outside and lost, affording extremely efficient thermal control.

Abstract: An MRI system includes a magnet which produces the main polarizing magnetic field. Variations in strength of this field are corrected by a temperature compensation system that calculates a compensating flux needed to maintain the field at constant strength. The compensating flux is calculated from changes in sensed magnet temperature and a magnet temperature coefficient. One or more correction coils are wound around the magnet and driven with the current necessary to produce the compensating flux.

Abstract: A method of Nuclear Quadrupole Resonance testing a sample containing a given species of quadrupolar nucleus, the sample being subjected to an inhomogeneous distribution of an extrinsic parameter having a variation over the sample over a particular range, comprises applying excitation to the sample at a plurality of different excitation frequencies to excite nuclear quadrupole resonance, such frequencies falling within the resonance frequency range for the nucleus corresponding to the range of the extrinsic parameter, and detecting the resonance response signal.

Abstract: Radio-frequency (RF) heating is used to accelerate the thermal equilibration of dielectrically lossy nuclear magnetic resonance (NMR) samples. High-power heating RF pulses are applied to the sample before lower-power measurement RF pulses, using any of the NMR probe coils. The heating pulses are offset in frequency relative to the measurement pulses, such that the heating pulses do not magnetically affect the spins of interest. Heating pulse sequences of decreasing power can be used to prevent the sample temperature from overshooting the desired equilibrium temperature. Heating RF pulses can pre-establish the thermal effects of both measurement-independent and measurement-dependent heating. For pre-establishing the thermal effects of measurement-dependent heating, the heating pulse transients are chosen to be proportional to subsequent measurement pulse transients.

Abstract: An absolute temperature measuring pulse sequence is executed and, subsequently, a relative temperature measuring pulse sequence is repeatedly executed. Since while a relative temperature can be measured from phase information, an absolute temperature requires frequency information, a time required in the relative temperature measuring pulse can be made shorter than that required in the absolute temperature measuring pulse sequence. Since the relative temperature reveals a temperature variation, if an absolute temperature at a given time is known, an absolute temperature at a subsequent time can be calculated from the relative temperature. Thus, a local internal temperature of the subject can be measured, with a shorter temporal resolution, with the use of the absolute temperature and relative temperature.

Abstract: Temperature in frozen tissue can be measured from magnetic resonance signals from the frozen tissue based on spin-spin relaxation time (T2) or based on relative intensity of the magnetic resonance signals. Short echo times are required, and use of tailored RF pulses, non-Cartesian readouts, and multi-slice and 3D k-space acquisitions are preferably employed.

Abstract: Net magnetic flux trapped in an NMR high temperature superconducting RF probe coil magnetically coupled with a main excitation DC magnetic field of an NMR device of which the probe is a part is reduced by moving the probe coil relative to the main magnetic field axis. There is a resulting interaction between the moving probe coil and the main excitation DC magnetic field to induce a current in the probe coil. The induced current reduces the net magnetic flux trapped in the probe coil. The probe coil is moved so the induced current is an AC current having an envelope with decreasing amplitude as a function of time. An electromechanical drive, produced by a magnetic field or an electrostatic field or a piezoelectric transducer attached to a substrate carrying the probe coil, provides oscillatory movement of the probe coil.

Abstract: A magnetic resonance imaging apparatus capable of measuring a temperature increase due to an application of RF magnetic fields for data acquisition purpose, and notifying an information on the measured temperature increase regularly to an operator, so as to secure the safety of a body to be examined. In this magnetic resonance imaging apparatus, the image data acquisition operation is controlled to acquire a phase information associated with a temperature change in an interior of the body to be examined, by displacing either an observation start timing or a radio frequency magnetic field application timing for a prescribed magnetic resonance signal in the magnetic resonance signal sequence from a normal timing for acquiring image data.

Abstract: A method of selectively heating targeted cells within a specimen while avoiding heating of non-targeted cells is provided. The method comprises the steps of:(a) determining at least one combination of magnetic field strength and radio wave frequency (strength-frequency combination) at which only the targeted cells will resonate when the magnetic field and the electromagnetic radiation are applied to the specimen orthogonal to one another; and(b) applying a magnetic field and a radio frequency wave to the targeted cells, the strength of the magnetic field and the frequency of the radio wave corresponding to the strength-frequency combination to the targeted cells, in order to cause nuclear magnetic resonance in the targeted cells, thereby increasing the temperature of only the targeted cells.

Abstract: A non-invasive apparatus and method for determining changes in the enthalpy of an object undergoing a freezing cycle using nuclear magnetic resonance (NMR) imaging (NMRI) techniques. Enthalpy is determined from the position of the ice interface of said object or, alternatively, from the liquid/solid ratio of the object.

Abstract: Inhomogeneities in the magnetic field in the vicinity of a superconducting NMR receiver coil are avoided by placing the probe, at about room temperature, within the magnetic field, cooling rapidly to just above the critical temperature of the superconductor and then controllably cooling the coil to operating temperature at a rate of 3 K./minute or less.

Abstract: An applicator for coupling an electromagnetic field to a sample to be imaged by magnetic resonance imaging, comprising an electrical periodic structure constructed so as to oscillate with substantially the same phase over its whole length.

Abstract: The volume magnetic susceptibility of an NMR probe is established and maintained at a desired value, such as a value characterizing other components of the probe, by a linear combination of partial pressures of respective fluids introduced into the sensitive volume of the probe.

Abstract: A variable temperature NMR probe having a RF coil surrounding a sample position and a fluid jacket for conveying fluid to control the temperature at the sample position. An RF electromagnetic shield prevents fluid in a fluid conveyor from affecting a NMR signal from the sample position.

Abstract: In Nuclear Magnetic Resonance (NMR) spectroscopy and microscopy, noise from the receiver coil of the probe limits sensitivity. This noise may be reduced by cooling the receiver coil. Noise may be even further reduced by use of a superconducting receiver coil. However, high temperature superconductors must be maintained at temperatures significantly below the critical temperature, typically in the range of 10-60 K for proper performance. The invention provides an apparatus for cooling an NMR receiver coil to a desired temperature using a closed circuit refrigeration system. A cold fluid is circulated to a heat exchanger which is in thermal contact with a thermally conductive substrate having low magnetic susceptibility. The receiver coil is deposited on a portion of the substrate located distally from the heat exchanger. In the preferred embodiment, the substrate is sapphire and the receiver coil is a superconductive oxide.

Abstract: A hyperthermia treatment apparatus includes an annular radio frequency (RF) antenna array with bolus that is compatible with a magnetic resonance imaging (MRI) machine. Antenna elements polarized parallel to the axis of the cylinder are used for forming a Specific Absorption Ratio (SAR) map as well as for directing the energy to accomplish hyperthermia. The array may be dynamically controlled to focus energy at any specified region within the cylinder. The array is positioned inside an MRI machine and is tuned to the machine's hydrogen resonant frequency. For treatment planning, the array is employed to form an SAR map via RF current density imaging. Using this map, array phase, amplitude, and temporal weighting are optimized until the SAR maxima is congruent with the treatment volume. For treatment, RF radiation is applied to the subject to induce heating of the treatment volume using these optimal array parameters. Temperature is periodically determined via noninvasive MRI methods (i.e.

Abstract: An MRI machine RF body coil is arranged so that it can also function as a hyperthermia treatment apparatus by arranging the RF body coil as an array of individual antenna element connected to each other by individually controllable switches and feedthrough elements.

Abstract: A magnetic resonance analyzing apparatus includes a sampling region; a first temperature stabilization assembly for maintaining the sampling region at a predetermined temperature; a magnet for applying a base magnetic field to the sampling region; a coil for applying a first 0.degree. phase excitation pulse to the sampling region at a first time, and a second 90.degree.

Abstract: A non-invasive measurement of a temperature distribution within a target body using a nuclear magnetic resonance imaging, capable of realizing a high speed and a high precision measurement, and accounting for a displacement of the target body during the measurement. The chemical shift data from the target body at each voxel in an imaging target region on the target body are collected with and without a temperature change of the target body, a difference between the chemical shift data collected with the temperature change and the chemical shift data collected without the temperature change at each voxel, and a temperature distribution image is constructed and displayed according to the difference calculated. The chemical shift data are preferably collected by using a phase mapping imaging sequence.

Abstract: A method is provided for carrying out proton magnetic resonance thermal analysis measurements. To this end, the method provides locating a sample within a coil forming part of an RF tuned circuit and applying a magnetic field to the sample. The sample is heated in accordance with a predetermined temperature regime. Pulsed RF energy is applied to the coil to generate a pulsed RF electromagnetic field which is applied to the sample. The magnitude of the magnetic field is adjusted to insure that the NMR frequency of the sample is substantially identical to the RF frequency. The resonant frequency of the tuned circuit is adjusted to compensate for temperature induced changes in the tuned circuit components and the sample. The energy of the pulsed RF energy is adjusted to obtain an optimum output from the RF tuned circuit. The RF tuned circuit output is recorded as a function of either time or temperature of the sample.

Abstract: A nuclear magnetic resonance spectrometer comprises a sample holder being arranged in a constant magnetic field of a predetermined direction. The sample holder comprises a rotor adapted to receive a sample under investigation. The rotor is arranged to rotate the sample about a first axis being inclined to the predetermined direction at an acute angle of, preferably, 54.7.degree.. For heating up the rotor, a laser is provided emitting a laser beam which is directed upon a surface of the rotor. The laser beam is adjustable in intensity by means of a control device.

Abstract: A hyperthermia applicator/MRI probe assembly for hyperthermia treatment of a subject. The assembly includes a hyperthermia applicator for heating target regions of a subject and a MRI probe which is utilized to monitor temperatures within the heating region. The hyperthermia applicator and MRI probe are coupled to a control system which receives information from the MRI probe and utilizes the information to control the hyperthermia applicator so as to maintain constant, desired temperatures within the heating region. The hyperthermia applicator/MRI probe assembly of the present invention allows for temperature control within about 0.5.degree. C.

Abstract: There is provided a method of and apparatus for thermographic imaging involving the use in electron spin resonance enhanced magnetic resonance imaging (ESREMRI) of a paramagnetic contrast agent having in its esr spectrum a temperature dependant transition. The ESREMRI enhancement of the free induction decay signal resultant on stimulating that transition with radiation of a set frequency or frequency band is itself accordingly temperature dependant.

Abstract: In the case of a nuclear magnetic resonance spectrometer containing a sample (1) arranged in a homogeneous magnetic field and being adjusted approximately to room temperature or a higher temperature, and a RF receiver coil (3) which is arranged around the sample (1) and cooled down to far below room temperature, for receiving nuclear magnetic resonance signals from the sample (1), at least certain parts of the RF receiver coil (3) are in thermal contact with a cooled platform (7). The connection lines of the RF receiver coil (3), the outer resonator wall (10), the pre-amplifier and the coolant transfer lines can be cooled by cold return gas. Thanks to this arrangement of the RF receiver coil (3), one achieves an optimum space factor, the thermal noise of the receiver system is drastically reduced, the Q factor of the resonant circuit is increased, and consequently the signal-to-noise ratio is improved.

Abstract: In an imaging method for spectroscopy of nuclear quadrupole resonances (NQR) with solid samples to which an RF field having a pulse duration t.sub.p with a base amplitude B.sub.10 constant over the sample length for magnetic excitation of NQR with resonance frequencies .omega. and with magnetic moments coupled to the nuclear quadrupole moments is applied and the NQR signal emitting from the sample is time-depentently detected, the RF field is superimposed by a position-dependent field contribution corresponding to a constant gradient B.sub.1.sup.x which yields together with the constant RF field a position-dependent RF field B.sub.1 (x), for each resonance frequency contained in the detected NQR signal the amplitude including its sign is determined, the measurements are carried out at different flip angles.sqroot.3.multidot..gamma..multidot.B.sub.1 (x).multidot.t.sub.

Abstract: Based on the relation that the higher the temperature of a portion to be measured, the lower becomes coherence of a nuclear spin at that portion, the present invention measures indirectly the temperature state of the portion to be measured from the change of intensity of NMR signals by utilizing this relationship. A transverse relaxation time is contained as one of the parameters in the relation between the signal intensity and the temperature; hence this transverse relaxation time is determined in advance for the portion to be measured and utilized in for the equation representing their relationship. This application discloses also an invention for determining a blood perfusion rate of the portion to be measured from the temperature data obtained in the manner described above.

Abstract: In a temperature-control device for samples, in particular for NMR spectroscopy, comprising a vessel (20) provided with an opening (19) for receiving a measuring sample (1), an inlet opening (10) for introduction of the fluid, an outlet opening (15) for the outflow of the fluid and a flow channel (18) through which at least a partial flow of the fluid is guided past the sample (1), as direct fluid flow, from the bottom to the top, there is provided at least one by-pass channel (17) which is arranged in such a way that an additional partial fluid flow can be guided past the upper area of the said sample (1) in the form of a by-pass fluid flow (7). This enables also the upper area of the sample (1) to be temperature-controlled in an efficient way so as to minimize the temperature gradient in the sample (1).

Abstract: A thermometry system comprising an implantable element having temperature dependent NMR properties, apparatus for applying an RF field to the implantable element, and apparatus for sensing the temperature dependent NMR response of the implantable element and for providing an output indication of temperature of the implantable element.

Abstract: A method of determining and imaging the temperature or temperature change of a liquid or solid object by NMR placing the object in a magnetic field B.sub.o at a temperature T.sub.o.sup.i, subjecting the object or a limited volume thereof to a first series of NMR imaging sequences to obtain first numerical values or images of molecular diffusion coefficients D.sub.o for individual points of the object or the limited volume thereof and recording the first series of images, maintaining the object or limited volume thereof at a temperature T.sup.i or waiting for a spontaneous change to the temperature, subjecting the object to a second series of magnetic resonance imaging sequences to obtain second numerical values or images of molecular diffusion coefficients D.sup.i for the same points of the object or the limited volume thereof and recording the second series of images, comparing point-by point the values or images of the diffusion coefficients D.sub.o.sup.

Abstract: A system is provided for regulating the field of a high homogeneity magnet. The fluid used for cooling the main magnet is placed in thermal contact with a high homogeneity auxiliary magnet in which is placed an NMR probe which controls the current supply to the two magnets connected in series.

Abstract: The static magnetic fields of an NMR imaging apparatus should be maintained constant in intensity in order to obtain satisfactory NMR images. Coils used to generate the static magnetic fields, and the supporting frames therefor, are subject to heat expansion due to changes in the temperature, which causes fluctuations in the intensity of the generated static magnetic fields. In the invention, the temperatures of the coils, frames, atmosphere and cooling water, and the amount of cooling water, are detected, and the energizing current for the static magnetic field coils is selectively controlled, based on the detected quantities, to thereby maintain constant the intensity of the generated static magnetic fields.

Abstract: An electromagnet for generating the constant magnetic field required in NMR tomography includes a superconductive coil system consisting of at least one circular cylindrical field coil (1) and at least one correction coil (2, 3) concentric with the field coil. The coil system is enclosed in a ferromagnetic cylindrical shell (13) whose influence on the homogeneity of the magnetic field is compensated by the particular dimensioning of the field and correction coils. The magnetic field is produced by the coil system (1, 2, 3) in the interior space defined by it, which space is accessible and suitable to receive the body presented for examination. The cylindrical shell (13) may be closed at its ends by ring-shaped ferromagnetic plates (14). The cylindrical shell (13), complete with plates (14), may directly form the exterior wall of the Dewar.

Abstract: A novel and improved method to detect indirectly a temperature of an object employing nuclear magnetic resonance techniques (NMR). The method involves obtaining an NMR spectrum to determine chemical shift, relaxation times, spin-spin couplings or quadrupole couplings for an element of a compound having at least one conformational isomer wherein the compound is influenced by a temperature of the object. Uniquely, the present invention may detect temperature in the body of an animal. Further, the present invention discloses a novel method to determine and monitor thermal physiological states in an animal as well as determine and monitor thermal states in an object. Because of the unique and advantageous non-invasive, non-destructive and non-ionizing properties, the present invention may be employed in an object or animal continuously.

Abstract: (CH.sub.3).sub.3 SiNSO is produced by the reaction of ((CH.sub.3).sub.3 Si).sub.2 NH with SO.sub.2. Also produced in the reaction are ((CH.sub.3).sub.3 Si).sub.2 O and a new solid compound [NH.sub.4 ][(CH.sub.3).sub.3 SiOSO.sub.2 ]. Both (CH.sub.3).sub.3 SiNSO and [NH.sub.4 ][(CH.sub.3).sub.3 SiOSO.sub.2 ] have fluorescent properties. The reaction of the subject invention is used in a method of measuring the concentration of SO.sub.2 pollutants in gases. By the method, a sample of gas is bubbled through a solution of ((CH.sub.3).sub.3 Si).sub.2 NH, whereby any SO.sub.2 present in the gas will react to produce the two fluorescent products. The measured fluorescence of these products can then be used to calculate the concentration of SO.sub.2 in the original gas sample. The solid product [NH.sub.4][(CH.sub.3).sub.3 SiOSO.sub.2 ] may be used as a standard in solid state NMR spectroscopy.

Abstract: In accordance with the invention, an improved sample heating apparatus is provided comprising an evacuated cylindrical envelope having a first portion of reduced diameter and capable of fitting into a cavity of a spectroscopic analysis device and capable of receiving a sample holder therein. A second portion of the cylindrical envelope has a larger diameter and heating means mounted therein. Radiation shielding means are also carried within the evacuated envelope of the larger diameter portion. The apparatus is also provided with gettering means to react with gases within the evacuated envelope.

Abstract: A lumped circuit loop-gap resonator is formed by a plurality of openings formed through a block of material. The openings form inductive loop elements and these are interconnected in a variety of possible networks by capacitive gap elements. String, star, ring and lattice networks are described.

Abstract: A nuclear magnetic resonance (NMR) cell for use in a gyro is shown which is maintained at a predetermined temperature, established by testing. Testing of each cell is conducted by heating the cell within a gyro to a series of temperatures and plotting the gyro bias (degrees/time) for each temperature within the series. At one temperature the magnitude of gyro bias will no longer increase but will start to decrease. This temperature turning point is the temperature at which the NMR cell should be maintained for zero temperature sensitivity of the gyro.

Abstract: This invention relates to methods and means for improving the sensitivity and signal-to-noise ratio of spin-echo measurements on samples, which have to remain at their own temperature and which have a non-negligible electrical conductivity. These are applied to noninvasive, localized, in vivo examinations of endogeneous tissue, organs, bones, nerves and circulating blood in the course of medical check-ups as well as for differential diagnostics and for the validation of therapeutic measures. This equipment comprises a system of magnets and an arrangement of transmitting and receiving coils encompassing the test person (patient) preferably completely, but at least the region of exploration. Means for the excitation as well as specialized low temperature equipment for the detection of NMR-signals emanating from a very small subregion are provided.

Abstract: A microwave resonator is formed by a cylindrical loop and one or more gaps which extend along its length. The loop is formed from a machineable insulating material and a layer of electrically conductive material is deposited over its surfaces.

Abstract: A nuclear magnetic resonance technique that allows simultaneous temperature determination and spectral acquisition. The technique employs a modification of the lock circuit of a Varian XL-100 Spectrometer which permits accurate measurement of the difference in resonance frequency between a primary lock nucleus and another, secondary, nucleus. The field stabilization function of the main lock circuit is not compromised. A feedback signal having a frequency equal to the frequency difference is substituted for the normal power supply in the spectrometer's existing radio frequency transmitter to modulate that transmitter. Thus, the transmitter's radio frequency signal is enhanced in a frequency corresponding to the resonance peak of the secondary nucleus. Determination of the frequency difference allows the determination of temperature without interference with the observed spectrum. The feedback character of the circuit and the presence of noise make the circuit self-activating.

Abstract: Accurate non-invasive temperature control of NMR samples without reduction of spectral quality is provided by placement of multiple sensors in the probe structure, the output of said sensors being weighted to provide an averaged reading of sample temperature in the receiver coil region.

Abstract: Apparatus and method for reduction of noise in NMR signals during high power heteronuclear decoupling experiments. A material is introduced into the evacuated area of the variable temperature probe to decrease collisional probability of ions generated in the interwall space of the evacuated envelop.