CN110987224B - Based on low field magnetic resonance T2Relaxation magnetic nanoparticle temperature calculation method - Google Patents

Based on low field magnetic resonance T2Relaxation magnetic nanoparticle temperature calculation method Download PDF

Info

Publication number
CN110987224B
CN110987224B CN201911238153.9A CN201911238153A CN110987224B CN 110987224 B CN110987224 B CN 110987224B CN 201911238153 A CN201911238153 A CN 201911238153A CN 110987224 B CN110987224 B CN 110987224B
Authority
CN
China
Prior art keywords
magnetic
temperature
field
relaxation time
magnetization
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201911238153.9A
Other languages
Chinese (zh)
Other versions
CN110987224A (en
Inventor
刘文中
张亚鹏
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Huazhong University of Science and Technology
Original Assignee
Huazhong University of Science and Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Huazhong University of Science and Technology filed Critical Huazhong University of Science and Technology
Priority to CN201911238153.9A priority Critical patent/CN110987224B/en
Publication of CN110987224A publication Critical patent/CN110987224A/en
Application granted granted Critical
Publication of CN110987224B publication Critical patent/CN110987224B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
    • G01K7/36—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using magnetic elements, e.g. magnets, coils

Abstract

The invention discloses a magnetic resonance T based on low field2A relaxation magnetic nano particle temperature calculation method belongs to the technical field of magnetic nano material testing. The invention will be referred to as T2Magnetic nanoparticles as temperature to magnetism contrast agentsMedium of field conversion, thereby creating T2Temperature behavior of the relaxation time. The magnetic nano-particles have good temperature sensitivity, so that T can be obtained2The relaxation time has a linear relationship with temperature by measuring T2The relaxation time reflects the temperature change, and high-precision temperature measurement is realized. The invention utilizes M-H magnetization curves of magnetic nanoparticles measured at different temperatures to obtain the magnetic field dependence of the temperature sensitivity of the induced magnetization of the magnetic nanoparticles, and accordingly, the magnetic nanoparticles matched with the main magnetic field of the low-field magnetic resonance instrument are optimized, the temperature sensitivity of the induced magnetization of the magnetic nanoparticles is maximized, and high-precision temperature measurement is realized.

Description

Based on low field magnetic resonance T2Relaxation magnetic nanoparticle temperature calculation method
Technical Field
The invention belongs to the technical field of magnetic nano material testing, and particularly relates to a low-field magnetic resonance T2A temperature calculation method of relaxed magnetic nanoparticles.
Background
The magnetic temperature measurement technology can penetrate through the surface to directly detect the internal temperature of an object, and is the leading edge of the technology with wide prospect in the subject fields of life, materials, microelectronics and the like. The magnetic temperature measurement is expected to open a new field of object internal temperature measurement (monitoring) of complex heat transfer structures or complex heat transfer processes. However, since the idea of magnetic temperature measurement was proposed in pierre curie centuries, the temperature measurement method and device realized by the magnetic method have not been broken through. According to the Curie paramagnetic theorem, a paramagnetic body obtains magnetic susceptibility through non-contact measurement, and then thermodynamic temperature T can be obtained through inverse ratio operation, but the method is only used for solving the temperature measurement problem of ultralow temperature physics below 1K at present.
If one wants to increase the signal-to-noise ratio in magnetic thermometry, one first has to find a more efficient temperature-to-magnetic field conversion element than the hydrogen nuclei, gadolinium. The magnetic nanoparticles appearing in recent years are nanoscale Fe3O4. Magnetic nanoparticles, which retain ferromagnetic properties and exhibit superparamagnetism over a wide temperature range, are one of the most efficient temperature-magnetic conversion materials known to date. Since 2008, a single-point temperature measurement technology using magnetic nanoparticles as temperature sensitive elements was studied by a plurality of research groups in sequence, and measurement accuracies of 0.3 degree and 0.1 degree were achieved in sequence by using various magnetic test systems. The cloche et al provides a temperature measurement method under the excitation of a single-frequency alternating magnetic field by studying the magnetization temperature sensitivity of magnetic nanoparticles under the excitation of a single-frequency alternating magnetic field, but the method requires the induction magnetization of the magnetic nanoparticlesHigh-precision measurement is carried out on the high-order harmonic information, and the measurement difficulty is high.
The bottleneck in high resolution magnetic temperature measurement is the search for a compatible system of nuclear magnetic and magnetic nano temperature measurement. In Nuclear Magnetic Resonance (NMR), superparamagnetic nanoparticles are thought to influence the transverse relaxation time (T)2)。
Disclosure of Invention
Aiming at the problems of low temperature measurement precision, poor linearity, difficult imaging and the like in the prior magnetic temperature imaging in the prior art, the invention provides a low-field magnetic resonance-based T2Method for calculating the temperature of a relaxed magnetic nanoparticle, the aim of which is to use the magnetic nanoparticle as T2Contrast agent under low-field (magnetic field intensity is less than or equal to 0.5T) magnetic resonance system by measuring T2And the relaxation time can be calculated to obtain the temperature, so that the high-sensitivity temperature measurement is realized.
To achieve the above object, according to a first aspect of the present invention, there is provided a low-field-based magnetic resonance T2A method for temperature calculation of relaxed magnetic nanoparticles, the method comprising the steps of:
s1, selecting different test temperature points, selecting alternative iron oxide magnetic nano reagents with different particle sizes, saturation magnetization and temperature sensitivities, and measuring an M-H magnetization curve of each alternative iron oxide magnetic nano reagent at each test temperature point;
s2, for each discrete excitation magnetic field value mu0Fitting the induced magnetization M and the temperature T measured by each alternative ferromagnetic oxide nanoparticle at different temperatures T under H to obtain the | dM/dT | -mu of each alternative ferromagnetic oxide nanoparticle0H curve;
s3, selecting the alternative iron oxide magnetic nano particles with the largest | dM/dT | value under the main magnetic field according to the main magnetic field value of the low-field magnetic resonance instrument to prepare the iron oxide magnetic nano particle aqueous solution;
s4, measuring the T of the aqueous solution of the iron oxide magnetic nanoparticles by using the low-field magnetic resonance instrument at different test temperature points2A relaxation time;
s5. based on the measured T at each temperature2Relaxation time, T fitting the aqueous solution of iron oxide magnetic nano particles2Relationship T of relaxation time and temperature2＝f(T)；
S6, measuring the T of the magnetic nano particle aqueous solution2Relaxation time, substituting the inverse function T ═ f-1(T2) Obtaining the temperature estimated value Test。
Preferably, the magnetic field intensity of the low-field magnetic resonance instrument is less than or equal to 0.5T.
Preferably, the test temperature point ranges from 37 ℃ to 40.4 ℃.
Preferably, the M-H magnetization curve of the candidate magnetic nanoparticle reagent is measured using an MPMS magnetic measurement system with a temperature control module.
Preferably, the measured M-H magnetization curve is as follows:
Figure BDA0002305107850000031
V＝πd3/6
wherein M represents the induced magnetization of the candidate magnetic nanoparticle reagent, N represents the number of magnetic nanoparticles per unit volume, and MsDenotes the saturation magnetization of a single magnetic nanoparticle, V denotes the volume of the magnetic nanoparticle, d denotes the core particle diameter of the magnetic nanoparticle, H denotes the excitation magnetic field,. mu.0Denotes the vacuum permeability, k denotes the boltzmann constant, and T denotes the absolute temperature.
Preferably, the | dM/dT | - μ0The H-curve expression is as follows:
Figure BDA0002305107850000032
preferably, the T is performed by using a CPMG pulse sequence2Measurement of relaxation time.
To achieve the above object, according to a second aspect of the present invention, there is provided a computer-readable storage medium having stored thereon a computer program, the computer program beingWhen executed by a processor, performs a low-field-based magnetic resonance T as described in the first aspect2A temperature calculation method of relaxed magnetic nanoparticles.
Generally, by the above technical solution conceived by the present invention, the following beneficial effects can be obtained:
(1) the invention will be referred to as T2Magnetic nanoparticles of contrast agents as mediators of temperature to magnetic field transition, thereby establishing T2Temperature behavior of the relaxation time. The magnetic nano-particles have good temperature sensitivity, so that T can be obtained2The relaxation time has a linear relationship with temperature by measuring T2The relaxation time reflects the temperature change, and high-precision temperature measurement is realized.
(2) The invention utilizes M-H magnetization curves of magnetic nanoparticles measured at different temperatures to obtain the magnetic field dependence of the temperature sensitivity of the induced magnetization of the magnetic nanoparticles, and accordingly, the magnetic nanoparticles matched with the main magnetic field of the low-field magnetic resonance instrument are optimized, the temperature sensitivity of the induced magnetization of the magnetic nanoparticles is maximized, and high-precision temperature measurement is realized.
Drawings
FIG. 1 shows a low-field-based magnetic resonance T according to an embodiment of the present invention2A flow chart of a method for calculating the temperature of the relaxed magnetic nanoparticles;
FIG. 2 is the M-H magnetization curve of magnetic nanoparticle reagent SHP-05 provided by the embodiment of the present invention at different temperatures;
FIG. 3 is the M-H magnetization curve of magnetic nanoparticle reagent SHP-10 provided by the embodiment of the present invention at different temperatures;
FIG. 4 is the M-H magnetization curve of magnetic nanoparticle reagent SHP-20 provided by the embodiment of the present invention at different temperatures;
FIG. 5 shows the magnetic field dependence of induced magnetization temperature sensitivity, i.e. | dM/dT | - μ, of magnetic nanoparticle reagents SHP-05, SHP-10 and SHP-20 provided by embodiments of the present invention0H curve;
FIG. 6 shows the measured temperature deviation using a magnetic resonance spectrometer minispec mq20 according to an embodiment of the present invention;
FIG. 7 shows measured temperature deviations measured using a magnetic resonance apparatus VTMR20-010-I according to an embodiment of the present invention;
FIG. 8 shows the measured temperature deviation using a magnetic resonance spectrometer minispec mq60 according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
The overall concept of the invention is as follows: using magnetic nanoparticles as T2A contrast agent. The magnetic nano particles have temperature-sensitive characteristics, the induced magnetization intensity of the magnetic nano particles in a magnetic field can be changed due to the change of temperature, the magnetization of the magnetic nano particles can correspondingly influence the environmental magnetic field of water protons around the magnetic nano particles, and the T of the water protons is further changed2The relaxation time. Temperature and T in a relatively small temperature range2The relaxation times have a linear relationship, and T2The relaxation time increases with increasing temperature by measuring T2And the relaxation time can be calculated to obtain the temperature, so that the high-sensitivity temperature measurement is realized.
As shown in FIG. 1, the present invention provides a low-field based magnetic resonance T2A method for temperature calculation of relaxed magnetic nanoparticles, the method comprising the steps of:
s1, selecting different test temperature points, selecting alternative iron oxide magnetic nano reagents with different particle sizes, saturation magnetization and temperature sensitivities, and measuring the M-H magnetization curve of each alternative iron oxide magnetic nano reagent at each test temperature point.
Within the temperature range of interest (e.g., around 37 degrees of human body temperature), different test temperature points are selected. Selecting alternative iron oxide magnetic nano-reagents with different particle sizes, saturation magnetization and temperature sensitivity. The M-H magnetization curves of these alternative magnetic nanoparticle reagents were measured using a temperature-controllable magnetic measurement system (e.g., SQUID-MPMS-XL7 instrument) at different sample temperatures, respectively.
The measured M-H magnetization curve can be described by the langevin model:
Figure BDA0002305107850000051
wherein M represents the induced magnetization of the candidate magnetic nanoparticle reagent, N represents the number of magnetic nanoparticles per unit volume, and MsDenotes the saturation magnetization of a single magnetic nanoparticle, V denotes the volume of the magnetic nanoparticle, d denotes the core particle diameter of the magnetic nanoparticle, the plate denotes the excitation magnetic field,. mu.0Denotes the vacuum permeability, k denotes the boltzmann constant, and T denotes the absolute temperature.
S2, for each discrete excitation magnetic field value mu0Fitting the induced magnetization M and the temperature T measured by each alternative ferromagnetic oxide nanoparticle at different temperatures T under H to obtain the | dM/dT | -mu of each alternative ferromagnetic oxide nanoparticle0And (4) an H curve.
And aiming at the same excitation magnetic field value, carrying out linear fitting on the induced magnetization M and the temperature T measured at different temperatures of the alternative magnetic nanoparticle sample, and solving the absolute value of the slope of a fitting curve of the alternative magnetic nanoparticle sample to obtain the temperature sensitivity | dM/dT | of the induced magnetization of the magnetic nanoparticles. Calculating | dM/dT | under all discrete excitation magnetic field values, and obtaining | dM/dT | -mu0And H curve, namely obtaining the magnetic field dependence of the temperature sensitivity of the induced magnetization of the magnetic nanoparticle sample.
|dM/dT|-μ0The H-curve can be described by the following formula:
Figure BDA0002305107850000061
and S3, selecting the alternative iron oxide magnetic nano particles with the largest | dM/dT | value under the main magnetic field according to the main magnetic field value of the low-field magnetic resonance instrument to prepare the iron oxide magnetic nano particle aqueous solution.
The temperature sensitivity of the induced magnetization of the magnetic nano sample has magnetic field dependence, namely the temperature sensitivity of the induced magnetization of the magnetic nano particles under different excitation magnetic fields is different, and the excitation magnetic field of the low-field magnetic resonance equipment is a fixed value. Therefore, according to the conditions, the induced magnetization temperature sensitivity value of the alternative magnetic nano-particles under the main magnetic field value of the used low-field magnetic resonance equipment is compared to select the most suitable T2And preparing magnetic nano particle aqueous solution samples with different Fe ion concentrations by using deionized water for testing.
S4, measuring the T of the aqueous solution of the iron oxide magnetic nanoparticles by using the low-field magnetic resonance instrument at different test temperature points2The relaxation time.
Despite T in vivo2The relaxation time is disturbed by a number of background factors in vivo, but can be influenced by using higher concentrations of magnetic nanoparticles T2Contrast agents, making the contrast agent change T2The main factors of (1). Further utilizes the higher temperature sensitivity of the magnetic nano-particles discovered before, researches that the temperature influences the peripheral water proton T by changing the induction magnetization of the magnetic nano-particles2Regularity of time, expected to pass the measurement of T under the condition2Relaxation times to obtain high resolution magnetic temperature measurements.
Performing T by using a low-field magnetic resonance instrument and adopting a CPMG (Carr-Purcell-Meiboom-Gill) pulse sequence at different magnetic nanoparticle aqueous solution sample temperatures2Measurement of relaxation time.
S5. based on the measured T at each temperature2Relaxation time, T fitting the aqueous solution of iron oxide magnetic nano particles2Relationship T of relaxation time and temperature2＝f(T)。
Measured T at different temperatures2Relaxation time, using least squares based linear regression to obtain T2Relationship between relaxation time and temperature, i.e. T2＝f(T)。
S6, measuring the T of the magnetic nano particle aqueous solution2Relaxation time, substituting the inverse function T ═ f-1(T2) Obtaining the temperature estimated value Test。
Direct pair to obtain T2f (T) performing an inverse operation to obtain an inverse function T ═ f-1(T2) And measured T is measured2The relaxation time is substituted into the inverse function to obtain the estimated temperature value TestFurther comparing the temperature with the set temperature of the sample to obtain the temperature measurement deviation Test-T, whereby the performance of the thermometric system is evaluated and verified.
Examples
1. The magnetic field dependence of the candidate magnetic nanoparticles with their temperature sensitivity of induced magnetization is obtained.
SHP series magnetic nanoparticle reagents SHP-05, SHP-10 and SHP-20(Ocean NanoTech) with nominal core particle diameters of 5nm, 10nm and 20nm are selected and made of Fe3O4The composite material is a magnetic core, and the surface of the magnetic core is coated with a single layer of oleic acid and a single layer of amphiphilic polymer, so that the composite material has good water solubility and monodispersity.
Respectively filling a certain amount of the alternative magnetic nanoparticle reagent into a small centrifuge tube, sealing and then measuring the M-H magnetization curve of the small centrifuge tube by using a SQUID-MPMS-XL7(Quantum Design, USA) magnetic measurement system at the sample temperature of 290K, 300K, 305K, 310K and 320K, wherein the range of the excitation magnetic field is 0 Oe-15000 Oe. The M-H magnetization curves of magnetic nanoparticle reagents SHP-05, SHP-10 and SHP-20 at different temperatures are shown in FIGS. 2, 3 and 4, respectively.
And aiming at the same excitation magnetic field value, carrying out linear fitting on the induced magnetization M and the temperature T measured at different temperatures of the alternative magnetic nanoparticle sample, and solving the absolute value of the slope of a fitting curve of the alternative magnetic nanoparticle sample to obtain the | dM/dT |. Calculating | dM/dT | under all discrete excitation magnetic field values, and obtaining | dM/dT | -mu0And H curve, namely obtaining the magnetic field dependence of the temperature sensitivity of the induced magnetization of the magnetic nanoparticle sample. The magnetic field dependence of induced magnetization temperature sensitivity of magnetic nanoparticle reagents SHP-05, SHP-10 and SHP-20 is shown in FIG. 5.
2. According to the parameters of the low-field magnetic resonance instrument and the | dM/dT | -mu of the alternative magnetic nano particles0H-curve selection for low-field-based magnetic resonance T2A magnetic nanometer reagent for measuring the temperature of the magnetic nanometer particles with high sensitivity of relaxation time.
As can be seen from the magnetic field dependence curve of induced magnetization temperature sensitivity shown in FIG. 5, the temperature-sensitive characteristic of the magnetic nano-reagent SHP-05 is far superior to that of the other two magnetic nano-reagents, and the optimal value is reached under the magnetic field of 0.3T. In addition, currently, the main magnetic field of common commercial low-field magnetic resonance analyzers is 0.5T, 0.47T, and the like. Based on instrument resources and | dM/dT | - μ0H Curve, selection of magnetic nanoparticle reagent SHP-05 for Low NMR-based T2Experiment of magnetic nanometer temperature sensitivity of relaxation time. Diluting the magnetic nanoparticle reagent SHP-05 with deionized water at different ratios to obtain three SHP-05 magnetic nanoparticle aqueous solution samples with different Fe concentrations, and measuring Fe concentrations of 32 μ g mL by using an atomic absorption spectrophotometer model iCE 3000-1、16.5μg mL-1、 10μg mL-1。
In particular, a minispec mq20 NMR spectrometer (Bruker, Germany) with a main magnetic field of 0.47T and a VTMR20-010-I NMR spectrometer (Nymei, Suzhou) with a main magnetic field of 0.50T were selected for T2Measurement of relaxation time. In addition, a minispec mq60 NMR spectrometer (Bruker, Germany) with a main magnetic field of 1.41T was selected for full comparison in experiments at medium and high fields.
3. T at different temperatures by using low-field magnetic resonance instrument2And (4) measuring the relaxation time.
Performing T on the three SHP-05 magnetic nanoparticle aqueous solution samples to be detected with different Fe concentrations by using a CPMG pulse sequence at different sample temperatures (the temperature interval is set to be 37-40.4℃)2Measurement of relaxation time. In addition, 5 consecutive repeated measurements are performed in order to reduce measurement errors, improve measurement accuracy, and verify repeatability. The temperature drift of the main magnetic field is a main source of magnetic resonance measurement errors, but the three selected nuclear magnetic resonance instruments are all provided with special main magnetic field constant temperature devices, so that the influence of the temperature drift of the main magnetic field in the experimental process is reduced to the lowest possible extent. And three magnetsThe vibration meter is provided with a temperature-changing probe, so that the accurate temperature control of the sample in the sample cavity can be realized.
4.T2Fitting of relaxation time and temperature T.
T at different temperatures obtained from the above measurements2Relaxation time, T is obtained by linear regression based on least square method2Relationship between relaxation time and temperature, i.e. T2＝f(T)：
y＝1.5666x+105.17，R2＝0.998@(10μg mL-1，0.47T) (1)
y＝1.7163x+80.699，R2＝0.9947@(10μg mL-1，0.50T) (2)
y＝0.476x+89.219，R2＝0.9322@(10μg mL-1，1.41T) (3)
y＝0.9704x+75.321，R2＝0.9736@(16.5μg mL-1，0.47T) (4)
y＝0.9473x+65.291，R2＝0.9701@(16.5μg mL-1，0.50T) (5)
y＝0.3919x+15.446，R2＝0.9953@(16.5μg mL-1，1.41T) (6)
y＝0.5243x+35.936，R2＝0.9986@(32μg mL-1，0.47T) (7)
y＝0.4769x+33.258，R2＝0.8574@(32μg mL-1，0.50T) (8)
y＝0.046x+33.608，R2＝0.4106@(32μg mL-1，1.41T) (9)
Wherein R is2Is a correlation coefficient of a linear regression equation, @ (x, x) is an experimental condition for data acquisition of each fitting equation, as in equation (1) @ (16.5. mu.g mL)-10.47T) showed a Fe concentration of 16.5. mu.g mL at different temperatures measured using a mq20 magnetic resonance instrument with a main magnetic field of 0.47T-1(ii) SHP-05 aqueous solution sample obtained T2Fitting of the relaxation time data to the corresponding temperature T.
5. Solving the inverse function T ═ f-1(T2) And obtaining the temperature measurement deviation Test-T。
The above T obtained by fitting2F (T), and finding the inverse function T f-1(T2) And measuring the obtained T2Substituting relaxation time to obtain temperature estimated value TestAnd comparing the temperature with the set temperature of the sample to obtain the temperature measurement deviation Test-T. The temperature measurement deviations obtained using the magnetic resonance apparatus minispec mq20, VTMR20-010-I and minispec mq60 are shown in FIGS. 6, 7 and 8, respectively.
From the practical experimental data, the T of the magnetic nanometer water solution with different concentrations under low field (0.47T and 0.50T)2The relaxation times are all linear with temperature T, and T2The relaxation time increases with increasing temperature T. In addition, from experimental data of minispec mq60 (main magnetic field 1.41T), it can be found that c (fe) is 16.5 μ g mL at the same temperature-1Sample and c (Fe) 10. mu.g mL-1T of the sample2The relaxation times are, however, almost comparable, which is clearly less normal. The possible reason is that the magnetic nanoparticles are more agglomerated into chains at high fields, resulting in the change in induced magnetization no longer following the langevin theorem. This indirectly indicates that the method is less suitable for high-field nuclear magnetization, and T is measured at low-field nuclear magnetization2Time becomes an optimal choice.
And the temperature error measured by a minispec mq20 magnetic field with 0.47T and a VTMR20-010-I nuclear magnetic resonance instrument with 0.50T is very small and better than 0.75 ℃.
The experiment shows that the magnetic nanoparticle solution is used as T2Contrast agents, exploiting the high temperature sensitivity of magnetic nanoparticles, by measuring T2The relaxation time reflects the temperature change, and high-precision temperature measurement can be realized. Therefore, the invention provides a magnetic resonance T based on low field2The effectiveness of the relaxation time high-sensitivity magnetic nanoparticle temperature measurement method.
It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (8)

1. Based on low field magnetic resonance T2A method for calculating the temperature of relaxed magnetic nanoparticles, the method comprising the steps of:
s1, selecting different test temperature points, selecting alternative ferromagnetic oxide nanoparticle reagents with different particle sizes, saturation magnetization and temperature sensitivities, and measuring the M-H magnetization curve of each alternative ferromagnetic oxide nanoparticle reagent at each test temperature point;
s2, magnetic induction intensity mu of each discrete excitation magnetic field0Fitting the induced magnetization M and the temperature T measured by each alternative ferromagnetic oxide nanoparticle at different temperatures T under H to obtain the | dM/dT | -mu of each alternative ferromagnetic oxide nanoparticle0H curve, μ0Represents the vacuum permeability;
s3, selecting the spare iron oxide magnetic nano particles with the largest | dM/dT | value under the main magnetic field according to the magnetic induction intensity of the main magnetic field of the low-field magnetic resonance instrument to prepare the iron oxide magnetic nano particle aqueous solution;
s4, measuring the T of the aqueous solution of the iron oxide magnetic nanoparticles by using the low-field magnetic resonance instrument at different test temperature points2A relaxation time;
s5. based on the measured T at each temperature2Relaxation time, T fitting of the aqueous solution of ferromagnetic oxide nanoparticles2Relationship T of relaxation time and temperature2＝f(T)；
S6, measuring the T of the magnetic nano particle aqueous solution2Relaxation time, substituting the inverse function T ═ f-1(T2) Obtaining the temperature estimated value Test。
2. The method of claim 1, wherein a magnetic induction of a main magnetic field of the low-field magnetic resonance instrument is less than or equal to 0.5 tesla.
3. The method of claim 1, wherein the test temperature point is in a range of 37 ℃ to 40.4 ℃.
4. The method of any one of claims 1 to 3, wherein the M-H magnetization curve of the alternative ferromagnetic oxide nanoparticle reagent is measured using an MPMS magnetic measurement system with a temperature control module.
5. A method according to any of claims 1 to 3, wherein the M-H magnetization curve obtained is measured as follows:
Figure FDA0002606173450000021
V＝πd3/6
wherein M represents the induced magnetization of the alternative ferromagnetic oxide nanoparticle agent, N represents the number of magnetic nanoparticles per unit volume, MsDenotes the saturation magnetization of a single magnetic nanoparticle, V denotes the volume of the magnetic nanoparticle, d denotes the core particle diameter of the magnetic nanoparticle, H denotes the magnetic field strength of the excitation magnetic field, k denotes the boltzmann constant, and T denotes the absolute temperature.
6. The method of claim 5, wherein | dM/dT | - μ0The H-curve expression is as follows:
Figure FDA0002606173450000022
7. a method according to any one of claims 1 to 3, wherein T is performed using a CPMG pulse sequence2Measurement of relaxation time.
8. A computer-readable storage medium, having stored thereon a computer program which, when executed by a processor, implements a low-field-based magnetic resonance T according to any one of claims 1 to 72A temperature calculation method of relaxed magnetic nanoparticles.
CN201911238153.9A 2019-12-05 2019-12-05 Based on low field magnetic resonance T2Relaxation magnetic nanoparticle temperature calculation method Active CN110987224B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201911238153.9A CN110987224B (en) 2019-12-05 2019-12-05 Based on low field magnetic resonance T2Relaxation magnetic nanoparticle temperature calculation method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201911238153.9A CN110987224B (en) 2019-12-05 2019-12-05 Based on low field magnetic resonance T2Relaxation magnetic nanoparticle temperature calculation method

Publications (2)

Publication Number Publication Date
CN110987224A CN110987224A (en) 2020-04-10
CN110987224B true CN110987224B (en) 2020-11-17

Family

ID=70090797

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201911238153.9A Active CN110987224B (en) 2019-12-05 2019-12-05 Based on low field magnetic resonance T2Relaxation magnetic nanoparticle temperature calculation method

Country Status (1)

Country Link
CN (1) CN110987224B (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113932939B (en) * 2021-09-26 2023-07-21 郑州轻工业大学 Ferromagnetic resonance temperature measurement method based on sweeping method
CN114199405B (en) * 2021-11-26 2022-08-16 华中科技大学 Temperature measuring method and system based on GRE (GRE) image and magnetic nanoparticles
CN114112097B (en) * 2021-12-08 2023-03-31 华中科技大学 Magnetic nanoparticle temperature measurement method based on electron paramagnetic resonance integral spectrum full width at half maximum
CN117035812B (en) * 2023-09-28 2024-03-08 辽宁嘉玉科技有限公司 Product coding and quick anti-counterfeiting identification method based on magnetic nanoparticles with different concentrations

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7719265B2 (en) * 2004-11-17 2010-05-18 Honda Motor Co., Ltd. Methods for determining particle size of metal nanocatalyst for growing carbon nanotubes
WO2014106160A1 (en) * 2012-12-31 2014-07-03 Georgetown University Metal particle mri contrast agents and methods of use
CN106556466B (en) * 2016-11-22 2018-11-02 华中科技大学 A kind of quick temperature measurement method based on magnetic nanometer magnetic intensity-temperature curve
CN109506805B (en) * 2018-12-17 2019-09-27 华中科技大学 A kind of Double deference thermometry based on magnetic nanometer

Also Published As

Publication number Publication date
CN110987224A (en) 2020-04-10

Similar Documents

Publication Publication Date Title
CN110987224B (en) Based on low field magnetic resonance T2Relaxation magnetic nanoparticle temperature calculation method
US7432714B2 (en) Method and device for on-chip magnetic resonance spectroscopy
Pelliccione et al. Two-dimensional nanoscale imaging of gadolinium spins via scanning probe relaxometry with a single spin in diamond
US9176206B2 (en) Effective-inductance-change based magnetic particle sensing
CN108663391B (en) Paramagnetic displacement-based magnetic nanoparticle concentration and temperature measurement method
US8461836B2 (en) Method and device for ex situ magnetic resonance analysis
Chiu et al. Multi-channel SQUID-based ultra-high-sensitivity in-vitro detections for bio-markers of Alzheimer's disease via immunomagnetic reduction
CN110179463B (en) Temperature and concentration imaging method of magnetic nanoparticles
Zhang et al. Iron oxide magnetic nanoparticles based low-field MR thermometry
Fodil et al. Dynamic sensing of magnetic nanoparticles in microchannel using GMI technology
Casieri et al. Self-diffusion coefficient by single-sided NMR
Xu et al. Ultralow detection limit of giant magnetoresistance biosensor using graphene composite nanoparticle label
Guitard et al. Local nuclear magnetic resonance spectroscopy with giant magnetic resistance-based sensors
Furman et al. Multiple-pulse spin locking in nanofluids
Wielinga et al. The spontaneous magnetization of the BCC Heisenberg ferromagnet Cu (NH4) 2Br4. 2H2O
Lee et al. Enhanced self-diffusion of adsorbed methanol in silica aerogel
Liu et al. Field-Swept Magnetic Particle Spectroscopy: A Single-Harmonic Method for Simultaneous Determination of Magnetic Nanoparticle Types and Quantities
Fodil et al. Model calculation of the magnetic induction generated by magnetic nanoparticles flowing into a microfluidic system: Performance analysis of the detection
Reig et al. Giant (gmr) and tunnel (tmr) magnetoresistance sensors: From phenomena to applications
Weitensfelder et al. Comparison of Sensitivity and Low Frequency Noise Contributions in GMR and TMR Spin Valve Sensors with a Vortex State Free Layer
CN112113991B (en) Non-local resistance type nuclear magnetic resonance measurement method
Haraszczuk et al. Monitoring Minute Changes of Magnetic Markers' Susceptibility by SV-GMR Needle-Type Probe
Arnold et al. Application of low frequency SQUID NMR to the ultra-low temperature study of atomically layered 3He films adsorbed on graphite
Novkovski Progress and limitations in magnetic field measurements
Xiao et al. Inversion of NMR relaxation measurements in well logging

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant