The present invention relates to an NMR (Nuclear Magnetic Resonance) analyzer for clinical examinations for analyzing a liquid component extracted from a human body.
Conventionally, NMR analyzers are known which comprise: a superconducting magnet for generating a powerful static magnetic field inside an arrangement space in which a sample is arranged; a liquid helium tank which houses the superconducting magnet and liquid helium for cooling the superconducting magnet; a liquid nitrogen tank which is provided on the outside of the arrangement space across the liquid helium tank and which houses liquid nitrogen; and a main body container which houses the liquid helium tank and the liquid nitrogen tank and which is formed in a ring-shape and compartmentalizes the arrangement space (for example, Patent Document 1). The liquid nitrogen tank is provided in order to suppress intrusion of heat from the outside into the liquid helium tank.
NMR analyzers of this type are used at research institutes, chemical substance manufacturing sectors, and the like for identifying synthesized or separated chemical substances and other purposes.
Meanwhile, in recent years, the use of NMR analyzers at medical facilities for analyzing liquid components extracted from a human body including blood, urine, sweat, saliva, spinal fluid, and organ extraction liquids is being considered.
However, with a conventional NMR analyzer such as that described in Patent Document 1, in order to prevent the intrusion of heat from the outside to a liquid helium tank that houses a superconducting magnet, a liquid nitrogen tank is provided on the outside of a sample chamber across the liquid helium tank. As a result, the NMR analyzer is too large to be used in medical facilities with limited installation space.
Patent Document 1: Japanese Patent Application Laid-open No. 2007-51850
An object of the present invention is to provide a compact NMR analyzer for clinical examinations which is suitable for use at medical facilities.
In order to solve the problem described above, the present invention provides an NMR analyzer for clinical examinations for analyzing a liquid sample including a liquid component extracted from a human body, the NMR analyzer for clinical examinations comprising: a solution feeding device that feeds a liquid sample; a solution feeding pipe that receives the liquid sample fed from the solution feeding device and that derives the liquid sample in accordance with a feeding operation of the solution feeding device; a superconducting magnet that encloses, around an axis of the solution feeding pipe, a housing space surrounded by a side wall of the solution feeding pipe such that a static magnetic field along the axis of the solution feeding pipe is generated inside the housing space; a housing container that houses the superconducting magnet and a coolant for cooling the superconducting magnet and that encloses the housing space around the axis of the solution feeding pipe; a main body container that has a negative pressure chamber whose interior is set to a negative pressure and that houses the housing container inside the negative pressure chamber and holds the solution feeding pipe by enclosing the solution feeding pipe around the axis thereof; a covering container that covers the housing container inside the negative pressure chamber; a cooling device that recondenses a coolant vaporized inside the housing container and that cools the covering container; a magnetic field correcting coil that is provided between the main body container and the solution feeding pipe and that corrects the static magnetic field generated inside the housing space by the superconducting magnet; a resonant circuit that includes a detecting coil enclosing the housing space around the axis of the solution feeding pipe between the solution feeding pipe and the magnetic field correcting coil, and applies high-frequency electromagnetic waves to a liquid sample inside the housing space, and that detects an NMR signal from the liquid sample; a transmitting/receiving unit that supplies high-frequency power to the resonant circuit and that receives an NMR signal from the resonant circuit; and a signal analyzing unit that creates data regarding a relationship between frequency and signal intensity based on the NMR signal received by the transmitting/receiving unit, wherein cooling of the covering container by the cooling device suppresses intrusion of heat from the outside into the housing container that is covered by the covering container, and by sequentially feeding a plurality of liquid samples of different types by the solution feeling device into the housing space, NMR signals of liquid samples inside the housing space can be sequentially detected.
According to the present invention, a compact NMR analyzer for clinical examinations which is suitable for use at medical facilities can be provided.
Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. The following embodiment is merely one specific example of the present invention and is not intended to limit the technical scope of the present invention.
With reference to
Specifically, the NMR analyzer 1 comprises: a magnetic field generating unit 2 for generating a static magnetic field inside a first through hole 2a; a recondensing unit (cooling device) 3 provided in the magnetic field generating unit 2 for recondensing a coolant that had vaporized in the magnetic field generating unit 2; a magnetic field correcting unit 4 for correcting homogeneity of a magnetic field in the first through hole 2a; a probe 5 provided in the magnetic field correcting unit 4 for holding a sample inside the first through hole 2a; a solution feeding pump (solution feeding device) 6 for feeding a sample to the probe 5; and a spectrometer 30 and an instructing device 40 which are electrically connected to the probe 5. In the present embodiment, a diameter D1 of the first through hole 2a of the magnetic field generating unit 2 is set to 20 mm.
The magnetic field generating unit 2 comprises: a tubular superconducting magnet 7; a helium container (housing container) 9 which houses the superconducting magnet 7 and a coolant (for example, liquid helium) 8 for cooling the superconducting magnet 7; a vacuum container (main body container) 12 which internally forms a vacuum chamber and which houses the helium container 9 inside the vacuum chamber; and a heat shield (covering container) 10 and a heat shield (covering container) 11 which enclose the helium container 9 between the helium container 9 and the vacuum container 12 in order to suppress thermal radiation from the vacuum container 12 (intrusion of heat into the helium container 9). The helium container 9 has two neck tubes 9a and 9b that extend upward. The heat shields 10 and 11 are respectively thermally connected to midsections of the neck tubes 9a and 9b. In addition, upper end sections of the neck tubes 9a and 9b respectively penetrate the vacuum container 12 and are opened to above. The recondensing unit 3 is attached to the neck tube 9a. Meanwhile, in the present embodiment, a lid (not shown) is attached to the neck tube 9b and closes the upper opening of the neck tube 9b. Alternatively, by providing another recondensing unit 3 on the neck tube 9b, efficiency of recondensation of liquid helium can be increased.
The recondensing unit 3 is for recondensing helium that vaporizes in the helium container 9 and rises in the neck tube 9a and for cooling the respective heat shields 10 and 11. Specifically, the recondensing unit 3 comprises: a two-stage cooling machine having a first stage set to a temperature of 30 K to 50 K and a second stage set to a temperature of 3 K to 4.5 K; a first sleeve 14 thermally connected to the first stage of the cooling machine; and a second sleeve 15 which is provided on an inner side of the first sleeve 14 and which is thermally connected to the second stage of the cooling machine. The first sleeve 14 is inserted into the neck tube 9a of the helium container 9 and, at the same time, thermally connected to an inner surface of the neck tube 9a at a contact position with the heat shields 10 and 11. The second sleeve 15 extends further downward than the first sleeve 14 and a tip section thereof is arranged in a vicinity of a liquid level of the liquid helium 8. In addition, the recondensing unit 3 uses the first sleeve 14 to cool the heat shields 10 and 11 via the neck tube 9a and uses the second sleeve 15 to recondense the vaporized helium and return the recondensed helium to the helium container 9. As described above, since the heat shields 10 and 11 are cooled via the neck tube 9a in the NMR analyzer 1 according to the present embodiment, a container for housing a coolant (for example, liquid nitrogen) need not be separately provided outside the helium container 9.
With reference to
The magnetic field correcting coil 4c is made of copper and is embedded in the tubular section 4a. The magnetic field correcting coil 4c is for generating a magnetic field such that an intensity of the magnetic field at a center position of the first through hole 2a remains constant regardless of the passage of time. Specifically, since the intensity of the magnetic field generated by the superconducting magnet 7 attenuates in proportion to elapsed time, the magnetic field correcting coil 4c generates a magnetic field that compensates for the attenuation amount of the intensity of the magnetic field. Moreover, the attenuation of the magnetic field intensity of the superconducting magnet 7 is detected by the spectrometer 30 (to be described later) based on a variation over time of a central frequency of an NMR signal of a reference substance. Examples of the reference substance include deuterium (2H) included in a deuterated solvent that is used as a solvent for a measurement object substance. Alternatively, the magnetic field correcting coil 4c may be constituted by a conducting wire wound around the tubular section 4a.
With reference to
The mounting member 16 integrally comprises a tubular body 16a inserted into the tubular section 4a of the magnetic field correcting unit 4 and a flange section 16b that protrudes outward from a lower end section of the tubular body 16a. In addition, the mounting member 16 is made of aluminum. The mounting member 16 is fixed to the magnetic field correcting unit 4 by screwing a bolt B into a female screw section (not shown) formed at both flange sections 4b and 16b in a state where an upper surface of the flange section 16b abuts a lower surface of the flange section 4b of the magnetic field correcting unit 4. The mounting member 16 can be detached from the magnetic field correcting unit 4 by unscrewing the bolt B. In the present embodiment, an outside diameter dimension D4 of the tubular body 16a is 9.8 mm.
The fixing plates 17a and 17b are fixed to an inner surface of the tubular body 16a at an interval corresponding to a length of the magnetic field correcting coil 4c , in other words, at an interval of 40 mm. Insertion holes 17c and 17d which vertically penetrate the fixing plates 17a and 17b in order to allow the solution feeding pipe 18 to be inserted are respectively formed in the fixing plates 17a and 17b. Alternatively, by forming vertically-penetrating holes in the fixing plates 17a and 17b in addition to the insertion holes 17c and 17d, air can be pumped into the probe 5 using a blower (not shown). As a result, temperature control of the solution feeding pipe 18 can be performed.
A midsection of the solution feeding pipe 18 is enclosed by the superconducting magnet 7, the vacuum container 12, and the magnetic field correcting coil 4c around the axis of the solution feeding pipe 18. Therefore, a static magnetic field along an axial direction of the solution feeding pipe 18 is applied by the superconducting magnet 7 to a sample inside the solution feeding pipe 18. Specifically, the solution feeding pipe 18 is a cylindrical glass pipe fixed to the respective fixing plates 17a and 17b in a state where the solution feeding pipe 18 is inserted into the insertion holes 17c and 17d. A sample housing space enclosed by a cylindrical side wall is formed in the solution feeding pipe 18. As shown, in the present embodiment, NMR signals of samples sequentially fed into the solution feeding pipe 18 (housing space) that is fixed to the magnetic field generating unit 2 can be detected. Therefore, unlike a conventional configuration in which NMR signals are detected by replacing test tubes for each sample, the entire NMR analyzer 1 can be downsized. Specifically, with a conventional NMR device that uses a test tube, homogeneity of a magnetic field in an NMR signal detection area may become unstable due to a mounting position of the test tube. For this reason, a rotating device for rotating the test tube around an axis thereof (for example, an air introducing unit for blowing air against a fin formed on the test tube) is required to suppress destabilization of the homogeneity of the magnetic field. In contrast, with the NMR analyzer 1 according to the present embodiment, since NMR signals of a plurality of samples can be detected using a solution feeding pipe fixed to the NMR analyzer 1, the rotating device can be omitted. As shown, with the NMR analyzer 1 according to the present embodiment, a rotating device and a container that houses liquid nitrogen for suppressing the intrusion of heat into the helium container 9 as described earlier can be omitted.
Furthermore, the solution feeding pipe 18 is shaped such that both end sections thereof are thinner than the midsection thereof which is fixed by the respective fixing plates 17a and 17b. In addition, an outside diameter dimension D5 of the midsection of the solution feeding pipe 18 is 3 mm. The RF coil 22 is provided at a position of the solution feeding pipe 18 between the respective fixing plates 17a and 17b.
With reference to
With reference to
With reference to
The spectrometer 30 comprises: an oscillator 32 that outputs a high-frequency signal with a predetermined frequency; a signal generating unit 31 that generates a signal that is outputted to the RF coil 22 based on the high-frequency signal from the oscillator 32; a signal transmitting unit 33 that transmits the signal generated by the signal generating unit 31 to the transmitting-side amplifier 51; a signal receiving unit 34 that receives an NMR signal from the RF coil 22 after a predetermined amount of time has elapsed from the timing of signal generation by the signal generating unit 31; and a signal analyzing unit 35 that analyzes the NMR signal received by the signal receiving unit 34. In the present embodiment, the signal generating unit 31, the signal transmitting unit 33, and the signal receiving unit 34 correspond to a transmitting/receiving unit 39.
As shown in
The instructing device 40 instructs the spectrometer 30 to detect NMR signals. Specifically, since the NMR analyzer 1 according to the present embodiment is configured to perform a plurality of NMR signal detections per sample, the instructing device 40 is configured to instruct timings of the plurality of detections. In addition, the instructing device 40 comprises a display unit (not shown) for displaying the chart shown in
Once again with reference to
The solution feeding pump 6 is configured so as to be capable of alternately feeding a sample and a cleaning solution. Therefore, using the solution feeding pump 6 enables a plurality of samples of different types to be sequentially fed into the solution feeding pipe 18. The cleaning solution is for washing away the sample of a previous detection which remains inside the solution feeding pipe 18.
As described above, the present embodiment comprises the recondensing unit 3 that cools the heat shields 10 and 11. Therefore, by cooling the heat shields 10 and 11 with the recondensing unit 3, intrusion of heat from the outside into the helium container 9 that is covered by the heat shields 10 and 11 can be suppressed. As a result, according to the embodiment described above, a liquid nitrogen container need not be separately provided outside the helium container 9 as was conventional, and a configuration more compact than conventional NMR analyzers with a liquid nitrogen container can be achieved.
Furthermore, in the embodiment described above, a sample can be fed from the solution feeding pump 6 into the solution feeding pipe 18, and an NMR signal of the sample inside the solution feeding pipe 18 can be acquired. Therefore, by sequentially feeding a plurality of samples of different types into the housing space by the solution feeding pump 6, NMR signals of the respective samples can be sequentially detected. As a result, according to the embodiment described above, a compact configuration can be achieved in comparison to conventional NMR analyzers in which samples of a plurality of types are respectively placed in different test tubes and NMR signals are acquired by sequentially replacing the test tubes. Specifically, a conventional NMR analyzer using test tubes requires attaching and detaching the test tubes to and from the analyzer. In such a case, since mounting positions of test tubes to the analyzer cannot be accurately adjusted each time a test tube is attached to or detached from the analyzer, a problem arises in that differences among mounting positions may destabilize the homogeneity of a static magnetic field in an NMR signal detection area. In order to circumvent this problem, NMR analyzers using test tubes are typically provided with a rotating device for rotating a test tube (for example, an air introducing unit for blowing air against a fin formed on the test tube), whereby a test tube is rotated around an axis thereof by the rotating device in order to average the magnetic field in the NMR signal detection area. In contrast, according to the embodiment described above, by sequentially feeding samples of a plurality of types to the solution feeding pipe 18, NMR signals of the samples of the plurality of types can be acquired using the solution feeding pipe 18 fixed to the vacuum container 12 while maintaining homogeneity of the magnetic field. Therefore, a conventional rotating device can be omitted and a compact configuration can be achieved.
While a configuration comprising two heat shields 10 and 11 is described in the present embodiment, the present invention is not limited thereto. For example, only one heat shield can be used as long as intrusion of heat to the helium container 9 can be suppressed to a desired level. Using only one heat shield is preferable from the perspective of compactifying the NMR analyzer 1.
The specific embodiment described above primarily includes an invention configured as described below.
In order to solve the problem described above, the present invention provides an NMR analyzer for clinical examinations for analyzing a liquid sample including a liquid component extracted from a human body, the NMR analyzer for clinical examinations comprising: a solution feeding device that feeds a liquid sample; a solution feeding pipe that receives the liquid sample fed from the solution feeding device and that derives the liquid sample in accordance with a feeding operation of the solution feeding device; a superconducting magnet that encloses, around an axis of the solution feeding pipe, a housing space surrounded by a side wall of the solution feeding pipe such that a static magnetic field along the axis of the solution feeding pipe is generated inside the housing space; a housing container that houses the superconducting magnet and a coolant for cooling the superconducting magnet and that encloses the housing space around the axis of the solution feeding pipe; a main body container that has a negative pressure chamber whose interior is set to a negative pressure and that houses the housing container inside the negative pressure chamber and holds the solution feeding pipe by enclosing the solution feeding pipe around the axis thereof; a covering container that covers the housing container inside the negative pressure chamber; a cooling device that recondenses a coolant vaporized inside the housing container and that cools the covering container; a magnetic field correcting coil that is provided between the main body container and the solution feeding pipe and that corrects the static magnetic field generated inside the housing space by the superconducting magnet; a resonant circuit that includes a detecting coil enclosing the housing space around the axis of the solution feeding pipe between the solution feeding pipe and the magnetic field correcting coil, and applies high-frequency electromagnetic waves to a liquid sample inside the housing space, and that detects an NMR signal from the liquid sample; a transmitting/receiving unit that supplies high-frequency power to the resonant circuit and that receives an NMR signal from the resonant circuit; and a signal analyzing unit that creates data regarding a relationship between frequency and signal intensity based on the NMR signal received by the transmitting/receiving unit, wherein cooling of the covering container by the cooling device suppresses intrusion of heat from the outside into the housing container that is covered by the covering container, and by sequentially feeding a plurality of liquid samples of different types by the solution feeling device into the housing space, NMR signals of liquid samples inside the housing space can be sequentially detected.
According to the present invention, since a cooling device for cooling the covering container is provided, intrusion of heat from the outside to the housing container that is covered by the covering container can be suppressed by cooling the covering container with the cooling device. As a result, according to the present invention, a liquid nitrogen container need not be separately provided outside the housing container as was conventional, and a configuration that is more compact than conventional NMR analyzers with a liquid nitrogen container can be achieved.
Furthermore, with the present invention, a liquid sample can be fed from the solution feeding device into the housing space of the solution feeding pipe and an NMR signal of the liquid sample in the housing space can be acquired. Therefore, by sequentially feeding a plurality of liquid samples of different types into the housing space, NMR signals of the respective liquid samples can be sequentially detected. As a result, according to the present invention, a compact configuration can be achieved in comparison to conventional NMR analyzers in which liquid samples of a plurality of types are respectively placed in different test tubes and NMR signals are acquired by sequentially replacing the test tubes. Specifically, a conventional NMR analyzer using test tubes requires attaching and detaching the test tubes to and from the analyzer. In such a case, since mounting positions of test tubes to the analyzer cannot be accurately adjusted each time a test tube is attached to or detached from the analyzer, a problem arises in that differences among mounting positions may destabilize the homogeneity of a static magnetic field in an NMR signal detection area. In order to circumvent this problem, NMR analyzers using test tubes are typically provided with a rotating device for rotating a test tube (for example, an air introducing unit for blowing air against a fin formed on the test tube), whereby a test tube is rotated around an axis thereof by the rotating device in order to average the magnetic field in the NMR signal detection area. In contrast, according to the present invention, by sequentially feeding liquid samples of a plurality of types to the solution feeding pipe, NMR signals of the liquid samples of the plurality of types can be acquired using the solution feeding pipe held by the main body container while maintaining homogeneity of the magnetic field. Therefore, according to the present invention, since a conventional rotating device can be omitted, a configuration that is more compact than conventional NMR analyzers using test tubes can be achieved.
Moreover, in the present invention, “a liquid component extracted from a human body” is a term that encompasses blood, urine, sweat, saliva, spinal fluid, organ extraction liquid, and the like.
According to the present invention, a compact NMR analyzer for clinical examinations which is suitable for use at medical facilities can be provided.
Number | Date | Country | Kind |
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2010-070568 | Mar 2010 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2011/001779 | 3/25/2011 | WO | 00 | 9/21/2012 |