DE102006049717B3 - Inaccessible place e.g. building wall, temperature determining method, involves determining magnetic scattering field due to magnetization of element and determining temperature of element from size of field based on field-reference data - Google Patents

Abstract

The method involves placing an element at a measuring point and changing characteristics of the element based on influencing temperature. The element consists of a ferro magnetic substance magnetized by a magnetic field using electromagnetic coils (3), for each temperature determination. Magnetic scattering field caused by the magnetization of the element is determined using superconducting quantum interference device (SQUID) magnetometer, after determining the field. Temperature of the element is determined from size of the scattering field based on magnetic scattering field-reference data. An independent claim is also included for a device for the contactless determination of the temperature at preferably inaccessible locations.

Description

The The invention relates to a method and a device with which the temperature in preferably inaccessible places, for example inside of liquid or solid objects, such as in human or animal bodies, in Refrigerated and frozen goods as well as in engineering materials, objects and structures, in particular not transparent for Electromagnetic radiation are contactless in a relatively simple manner and online, d. H. timely, can be determined or monitored, without a permanent or temporary incriminating, disruptive or damaging To take effect by the temperature measurement in purchasing. The temperatures can in a range of 10 K to 1000 K with an accuracy of up to 0.1K.

temperature measurements are predominantly carried out by methods involving thermal contact between the measuring object and the sensor required (for example M. Paarmann and A. Pfannenstein: Temperature measurement in biological Tissues, Wiss. Zeitschrift. Chemnitz University of Technology. 33, 1991, 333-348).

A well-known method uses liquid thermometers, which in the object to be measured must be immersed or pressed to the same.

A others very often applied method uses per se well-known thermocouples, their active element, the solder joint, also must have close thermal contact with the object to be measured.

• a) die Messung der Temperatur von begrenzten Regionen im Inneren des menschlichen Körpers,
• b) die Temperaturmessung im Innern von Betonteilen während und nach ihrer Herstellung und
• c) die Messung der Temperatur in Kühl- und Gefriergut.

Numerous methods are known for contactless temperature measurement. To illustrate your essential features, we will describe three specific applications below:

• a) the measurement of the temperature of limited regions in the interior of the human body,
• b) the temperature measurement in the interior of concrete parts during and after their manufacture and
• c) the measurement of the temperature in refrigerated and frozen goods.

A well-known contactless functioning method consists in the measurement of the electromagnetic radiation emitted by the measurement object emanating from a receiver (Radiation thermometer). In the above applications, radiation thermometers fail to since the matter between the object to be measured and the receiver is the radiation strongly absorbed.

Known is in principle the use of magnetic resonance tomography for the application a), since the relaxation times measured with this method are independent of the Suspend the temperature of the DUT (eg A. Oppelt, in: W. Andrä & H. Nowak (Eds.) Magnetism in Medicine, Physical Principles and Technology, Wiley-VCH, Berlin / New York etc.1997, 305-347 or W. Wlodarcyk et al .: Comparison of four magnetic resonance methods for mapping small temperature changes. Phys. Med. Biol. 44, 1999, 607-624). Because of the very high Apparition and the relatively low accuracy was However, this method has not yet been put into practice.

When another method for the application a) is the use of sound waves (ultrasound) known (for example, R. M. Arthur et al .: Application of acoustical thermometry to non-invasive monitoring of internal temperature during laser hyperthermia, Med. Phys. 30, 2003, 1021-1029). A serious disadvantage but is given by the fact that all interfaces between areas with different density lead to reflections.

For application a) are in the human body such interfaces present and can, for. B. in gas bubbles in the intestine, completely prevent access to the measurement object. In application b) the different porosity makes concrete the use unsuitable. In application c) the interfaces between the cooling or frozen food and packaging material for disturbing sound reflections.

Of Another is an electrical method, impedance tomography, also described (see E. Gersing et al .: Problems involved in temperature measurements using BIT, Physiolog. Measurement 16 suppl., 1995, A153-A160).

There the electrical impedance in a very complex way from the electrical conductivity of the object to be measured and of capacities depends on the measurement setup, This method has not yet been put into practice.

Also the use of X-rays for temperature measurements was investigated (B.G. Fallone et al .: Noninvasive thermometry with a clinical X-ray CT scanner, Med. Phys. 9, 1982, 715-721). These Method has for the application a) the disadvantage of radiation exposure, especially at Measurements made several times or over a longer one Period must be continuous. For applications b) and c) the effort is too big.

It is also known to use magnetic properties of the measurement object or of a sensor in the measurement object for contactless measurement of the temperature. An example is in DE 32 41 009 A1 described. Here, the temperature dependence of the magnetic resonance frequency of a Ferritkör exploited, which is mounted in the test object. The ferrite body is in the interior of a permanent magnet, which is required for the setting of a magnetic field at the location of the ferrite. This complicated structure and the high frequency of the superimposed alternating field (in the GHz range) are the reasons why this method could also practically not be introduced.

Another magnetic temperature measurement method uses the change of the magnetic hysteresis loop or the coercive field strength as a function of the temperature ( FR 2 532 751 A1 ). For this purpose, a magnetic body is brought as a sensor to the place whose temperature is to be measured. From the outside, a high-frequency magnetic field is applied, which acts on the sensor. The magnetization of the sensor, which also changes periodically in this primary field, is detected by induction coils. From the known per se temperature dependence of the permeability of the sensor material can then be concluded that the sensor temperature.

A disadvantage of this method, especially for application a), is that the magnetic field strengths required for a useful signal in the range of high frequencies also lead to the excitation of eddy currents in electrically conductive objects. This not only falsifies the signal but also heats up the object, in the case of application a) unacceptably high as soon as the product of amplitude and frequency of the primary field exceeds 4.85 × 10 ⁸ A / (s · m) (IA Brezovich: Low frequency hyperthermia: capacitive and ferromagnetic thermoseed methods, in: PR Palivan & FW Hetzel (Eds.), Medical Physics Monograph 16, American Institute of Physics, New York 1988, 82-111). In the applications b) and c), the electrical conductivity of the object may be even higher than in human body tissue and therefore lead to stronger heating.

In addition, the sensitivity of the temperature measurements using the temperature dependence of the ferromagnetic permeability is very low, such as in the US 4,136,683 can be taken from the given table. These values correspond to a mean temperature coefficient (1 / χ) · (dχ / dT) = 0.0015 K ^-1 . For example, this is far too low for a temperature measurement in the human body. Considering in the US 4,136,683 given maximum permissible mass of small particles that may be introduced into the body for such a measurement, the measurement for this sensitivity would require an immense and practically unachievable effort of the measuring apparatus, in addition the Suszeptibiltäten of paramagnetic and diamagnetic substances by orders of magnitude smaller are as those of ferromagnetic substances.

In the DE 32 05 460 A1 a temperature measurement based on the known per se temperature dependence of the magnetic remanence is presented, although it is expressly assumed that there is a reversible relationship between the remanence induction and the temperature. This necessary condition for the application of the method and is fulfilled only in a few special cases, such as when using permanent magnets in the temperature range far below their Curie temperature. So will in the DE 32 05 460 A1 also discloses only a permanent magnetic transducer.

Also based on measuring the magnetic remanence is a long-known measuring method ( DE-OS 1 573 185 ) for measuring the maximum temperature, wherein a designated as an indicator ferromagnetic substance is first magnetized at a predetermined temperature, which is below the temperature to be measured, and only then exposed to the temperature to be measured. The measurement of the remanence takes place at a later time, when the indicator has again reached the said starting temperature. In this way, the maximum reached temperature can be determined, which has experienced the indicator during the entire process with the completed temperature change. The determination of the actual absolute temperature of the indicator is not possible.

Furthermore, a special measuring element as well as a method for its production is known (US Pat. DE 38 21 620 C2 ). The Meßmhlerelement consists of ferroelectric substances, wherein the temperature dependence of the dielectric constant is utilized. This method is not suitable for exact temperature measurements in preferably inaccessible places, for example in human or animal bodies as well as in technical objects that are not transparent to electromagnetic radiation.

Of the Invention is based on the object, the temperature of preferred remote or difficult or inaccessible locations, for example inside of solid or liquid Objects as well as in bodies, which is not transparent for electromagnetic radiation are, with a low economic, procedural and handling costs for the measurement or monitoring as possible exact and object compatible contactless to determine, without that in the objects introduced sensors or other large volume Elements or the measuring method itself is a significant burden or disturbing, damaging or cause any other adverse effect.

For medical Applications are in particular the requirement minimally invasive Interventions in human and animal bodies that are patient friendly Introduction of measuring probes as well as their highest biological and other compatibility in the foreground.

at technical use, the process should not be noticeable disadvantages for the to be measured or monitored Objects with regard to their intended use, such as function, stability and permanence, bring.

Furthermore The sensor should not contain its own energy source (eg battery) and therefore in the object for be usable for any length of time.

According to the invention is in or on the measuring object an element made of a ferromagnetic substance, For example, in the form of a small ball, positioned, which magnetized to any temperature detection by an external magnetic field becomes. Each time after switching off this magnetic field, the size of the the remanence magnetization of the ferromagnetic substance of the element outgoing magnetic stray field determined. From this size will on the basis of given or to the element used magnetic stray field reference data the temperature of the element is determined.

The element of ferromagnetic substance, depending on the intended use z. Example of iron oxide, such as Fe ₃ O ₄ and γ-Fe ₂ O ₃ or mixtures thereof, or mixed oxides of iron oxide and titanium oxide, in particular due to its good realizable contour and small size and, for example, for medical and food applications due to its biocompatibility and other harmless relatively aufwandgering and easily be placed in or on the measurement object. Before each temperature measurement of the measurement object, the ferromagnetic element is magnetized defined by an (external) magnetic field. It is advantageous that said element for this purpose no active energy sources, such as batteries, rechargeable batteries, etc., or must be electrically related to those which not only the life, but also the handling and use of the in or on the measurement object to be positioned Element, and thus restrict the use of the method itself or even question it.

With these benefits of the method, the element relatively easily, especially in civil engineering Facilities and installations (during their manufacture and / or use) be fitted or attached, without their function, use, stability resistance etc. to affect. In this way, you will be without big Additional effort and in particular without specially required additional maintenance the objects in largely arbitrary civil engineering facilities, for example Concrete and masonry buildings, unique, continuous and permanent Temperature measurements and monitoring for use and control purposes. With The invention is a comparatively low on the practice given online temperature control, especially not rarely for safety reasons costly Cooling additives for emerging Structures attached be or (at least without temperature control for required being held).

The ferromagnetic elements, their whereabouts in the structural engineering Equipment and installations for the above reasons of the principle for selbige is safe, must thus for temperature detection even with the required long-term or permanent applications may not necessarily be removed or replaced become. The advantages described apply equally, too for higher temperature ranges up to the respective boiling temperature for applications in fluid media and liquid reservoirs.

Also for temperature measurement and monitoring of cooling and frozen food, for example, for the detection control of this respectively prescribed cold chain, can the proposed elements, d. H. small ferromagnetic beads, for example, a nickel-copper alloy with about 35% copper, usually problematic and above all harmless be used. In the simplest way and handling can also for these low operating temperatures One-time, repeated and permanent temperature measurements in a timely manner carried out be removed from the cooling environment for a short time or longer without the measurement objects to have to remove. The ferromagnetic substances for in or on the refrigerated goods to dumping elements can so chosen that these materials, such as titanomagnetites, harmless and thus without hesitation for dealing with food and beverages are.

For medical applications, the small ferromagnetic beads may, for example, consist of titanomagnetite and are thus biocompatible even with prolonged retention in the human or animal body and essentially without any organism-damaging side-effects for the patient. Without the said element necessarily having to be repositioned in or on the body for each measurement or control, repeated sufficiently exact measurements and controls are also made possible in a 'patient-friendly' manner (even for beads of the smallest dimensions), even for long-term monitoring. Self-renewed (or further / changed positioning, for example other parts of the body) would be due to the mentioned contour and small size of the ferromagnetic elements (in addition, without required own energy sources, such as batteries and rechargeable batteries) minimally invasive and associated with no major or even unreasonable burden on the patient. This would be the proposed temperature measurement or control for the doctor very good diagnostic and / or therapeutic options, advantageously applicable even in clinical routine, given without burdening the patient separately or health by the investigation method additionally put at risk.

The under claims include further advantageous method and device features as well as possible applications the invention. So can For example, for the elimination of interference in itself known difference evaluations be carried out with magnetization of different polarity, especially applications of the smallest ferromagnetic elements (beads) and thus very sensitive measurements, among others for medical Applications as well as for the use with high sensor distance, (eg in large structural engineering Facilities).

Also can by directional stray field measurements these ferromagnetic elements, for example by use of known three-component magnetometers, with the temperature detection and evaluation additional Information, eg. B. over the position of the sensor to be won. At the mentioned medical Applications is for temperature detection / control determines the exact position of the or attached element crucial, especially since the same by most different influences its location in the body change in the long run can. In such cases would be through the said direction-dependent stray field measurement additionally the position of the element in or on the object can be determined or controlled.

The Invention is not on the mentioned applications and their intended use limited.

The Invention will be described below with reference to the drawing embodiments be explained in more detail.

It demonstrate:

1 : Temperature measurement inside the human body

1a : Temperature measurement in the female breast

1b : Comparison temperature measurement away from the object to be measured 1a

2 : Temperature measurement inside a building

embodiment 1:

In 1 is the measurement or control of temperature in the treatment of breast cancer by local magnetic hyperthermia or thermal ablation shown. For this purpose (cf. 1a ) using a minimally invasive method, a temperature probe 1 in or immediately adjacent to the carcinoma in the female breast 2 landfilled. The temperature probe 1 is a small sphere (diameter about 1 mm or even smaller) of biocompatible Titanomagnetit the composition Fe _2.3 Ti _0.7 O ₄ .

An electromagnetic coil 3 5 cm) by hand or by means of a suitable holder (not shown in the drawing for reasons of clarity) from the outside tightly against the breast to be examined 2 with the internal temperature probe 1 held for a period of about 0.5 s by a direct current, at the location of the temperature probe 1 generates a primary magnetic field of strength H _P ≈ 8 kA / m and the temperature probe 1 magnetized. After this primary magnetic field has decreased to zero (switching off the direct current), the stray field H _St becomes the temperature probe 1 through one in the center of the electromagnetic coil 3 attached magnetic field sensor 4 measured. The strength of this stray field is H St = (2M R / 3) · (R / A) 3 , (1) where MR is the remanence magnetization, R is the radius of the temperature probe 1 and A is the distance of the center of the electromagnetic coil 3 from the temperature probe 1 are. With a known dependence of the remanence MR on the temperature and constant ratio (R / A), the temperature at the location of the temperature probe can be determined from H _St 1 be determined.

To the influence of interference fields, such. As the earth's magnetic field, at the location of the magnetic field sensor 4 After a short waiting time of approx. 1 s, the magnetization of the temperature probe is eliminated 1 through the electromagnetic coil 3 with reversed primary field H _P and the difference of the two measured values of H _St formed.

From equation (1), the expected strength of the stray field H _St. If the M _R value is known, the sensitivity of the magnetic field sensor is known 4 to be chosen so that the temperature change of MR can be reliably detected. At a distance of the center of the electric coil 3 to the temperature probe 1 of A = 3 cm, a radius the temperature probe 1 of R = 0.5 mm and the above composition of titanomagnetite can be used as a magnetic field sensor 4 a magnetoresistive sensor (detection limit δH <10 ^-4 A / m) or a flux-gate sensor (δH <10 ^-5 A / m) can be used to detect a temperature change of 1K. Repeated measurement and averaging of the measured values can further increase the sensitivity of the temperature measurement.

The sensitivity can be further increased by comparison measurements. This will be a second external temperature probe 5 used at a known temperature (eg 37 ° C), which passes through another electromagnetic coil 6 (like those in the chest 2 introduced temperature probe 1 through the electromagnetic coil 3 ) is magnetized (see. 1b ). After the primary magnetic field of the coil 6 for magnetizing the temperature probe 5 has fallen to zero, equally the stray field H _{St of} the temperature probe 5 through one also in the center of the electromagnetic coil 6 attached magnetic field sensor 7 measured.

Both the temperature probes 1 and 5 , as well as the associated measuring arrangements (electromagnetic coil 3 respectively. 6 with magnetic field sensor 4 respectively. 7 ) as well as the magnetization conditions of the temperature probes 1 and 5 (Duration and size of the direct current to build the primary magnetic field) are identical. However, the distance B between the magnetic field sensor 7 and the temperature probe 5 variable and will be before the start of the said heat treatment of the female breast 2 calibrated so that the signal of the magnetic field sensor 7 to the same value as the signal from the magnetic field sensor 4 is set. In the heat treatment of the female breast 2 the difference of these signals is formed.

embodiment 2:

In 2 is the temperature measurement inside a on a floor 8th built building 9 , For example, a masonry, a building wall or a concrete structure shown.

In the manufacture or after completion of buildings with greater wall thicknesses, especially in concrete structures, created by chemical processes during the setting of the building material heat, which can lead to harmful cracking in the building. To counteract this heating, it is cooled, especially with larger concreting volumes. For optimum cooling, it is important to know the temperature in the building in order to adjust the required complex cooling capacity. The temperature measurement can according to the embodiment 1 respectively. Into the interior of the building 9 is (either immediately with its production or after its completion) a temperature probe 10 introduced, which in contrast to medical applications, in particular in or on the human organism, here must not be biocompatible, so that the selection of usable ferromagnetic materials with a suitable temperature dependence of the remanence is greater. For temperatures around 10 ° C, for example, nickel-chromium alloys with about 7% chromium or nickel-copper alloys with about 31% copper can be used.

In buildings, the measurement of the local temperature distribution over a long period of time may be important in order to calculate harmful mechanical stresses which may occur, for example. B. in extreme sunlight or local cooling caused by cold winds. For this purpose could also be temperature probes at different locations in the building 9 are introduced (not shown for reasons of clarity), which are suitably selected for respective temperature ranges of the ferromagnetic material or have a specific composition. For temperatures around the freezing point z. B. nickel-copper alloys with about 32% copper, suitable for temperatures around 100 ° C, such alloys with about 22% copper.

The size of the building 9 introduced temperature probe 10 depends in each case essentially on the distance between the temperature probe 10 and a magnetic field sensor provided for this purpose 11 which is at the center of a corresponding electromagnetic coil 12 is arranged. When the temperature probe 10 for example, in the middle of the building 9 with a wall thickness of 2 meters (distance A between the center of the building 9 applied electromagnetic coil 12 and the internal temperature probe 10 is on the order of 1 m) and it is a temperature probe 10 made of magnetoresistive material, then should for a reliable temperature-dependent detection of the remanence magnetization MR at spherical shape of the temperature probe 10 whose radius R is about 10 mm.

It should be noted that for the generation of the primary field by the electromagnetic coil 12 whose radius must be correspondingly large, so that the primary magnetic field at the location of the temperature probe 10 is sufficiently strong. As a rule of thumb, the radius of the electromagnetic coil 12 should be approximately equal to the distance A.

embodiment 3:

Not shown in the drawing, the temperature control inside of refrigerated or frozen, at which predetermined temperature limit values during storage and during transport must not be exceeded. Control measurements should be made inside the premises, although these locations are not immediately accessible. The temperature measurement again corresponds to the method described in the aforementioned embodiments. In the interior of the refrigerated or frozen goods a temperature probe of the type described is introduced at the point to be measured, the ferromagnetic material is briefly magnetized by an external (located outside of the refrigerator or freezer) electromagnetic coil. A magnetic field sensor arranged in the center of the electromagnetic coil measures the stray magnetic field of the temperature probe magnetized by the electromagnetic coil after changing, in particular switching off, the primary magnetic field. From the comparison of these stray field measured data with predetermined or specially determined reference data, the temperature of the temperature sensor located here in the item to be cooled or frozen is again determined or checked. This measurement or control is, as in the other embodiments, online or promptly possible, so that here an excess of the maximum cooling or freezing temperature not only in retrospect on the basis of records, but can be detected and reported immediately.

The Application and measurement conditions are similar to the second embodiment. distances between the interior of the refrigerator or frozen food (temperature probe) and the magnetic field sensor in the range of one or more meters. Therefore (for spherical temperature probes) Probe radii of one or more centimeters required. There the probes are generally coated with a dense coating, e.g. B. from a biocompatible Fabric, can be provided is also for Food the fabric selection, as in the second embodiment described, possible. For temperatures around - 30 ° C are then For example, nickel-chromium alloys with about 8% chromium or nickel-copper alloys suitable with approx. 35% copper.

Also Here are again several measuring points, d. H. the introduction of several Temperature probes at different locations of the cooling or Frozen goods, conceivable.

1, 5, 10

temperature probe

2

chest

3, 6, 12

electrical Kitchen sink

4, 7, 11

Magnetic field sensor

8th

ground

9

building

A, B

distance

Claims (26)

A method for the contactless determination of the temperature in preferably inaccessible places, in which an element is placed at the measuring location, the properties of which change as a function of the temperature acting thereon, characterized in that the element consists of a ferromagnetic substance, which at each temperature detection is magnetized by a magnetic field, that in each case after termination of this magnetic field from the remanence magnetization of the magnetized ferromagnetic substance of the element outgoing magnetic stray field is determined and that in each case from the size of this stray field based on predetermined or the element used magnetic stray field reference data, the temperature of the element is determined. Method according to claim 1, characterized in that that the magnetization of the element placed at the site by Circuit of one by means of one or more electromagnetic Coils generated magnetic field occurs. Method according to claim 1, characterized in that that the magnetization of the element placed at the site by one or more each in the magnetization region of the element to be brought magnets takes place. Method according to claim 1, characterized in that that the control of the magnetization of the placed at the site Elements by one in the area between the element and means for generating the magnetic field moving magnetic shield takes place. Method according to claim 1, characterized in that that the stray field of the magnetized element by a magnetometer is measured. Method according to claim 5, characterized in that that a SQUID magnetometer is used as the magnetometer. Method according to claim 5, characterized in that in that a magnetoresistive sensor is used as the magnetometer. Method according to claim 5, characterized in that that use as a magnetometer, a Hall sensor place. Method according to claim 1, characterized in that that the stray field of the magnetized element immediately after Shutdown of the magnetic field for the magnetization of the element is measured. Method according to claim 5, characterized in that that for the elimination of interference fields the magnetization successively each with the opposite sign takes place and from the difference of the stray field measurement results the temperature of the element is determined. Method according to claim 5, characterized in that that for obtaining the position of the element in or on the measurement object for determining the stray magnetic field of the ferromagnetic Substance of the element is a three-component magnetometer use. Method according to claim 1, characterized in that that the reference data for determining the temperature of the determined magnetic stray field of the ferromagnetic substance of the element as tables, lists, diagrams are present and that the temperature determination made manually from the comparison with the reference data. Method according to claim 1, characterized in that that the reference data for determining the temperature of the determined magnetic stray field of the ferromagnetic substance of the element in electronically evaluable form, for example as a database, and that the temperature determination from the comparison with the reference data is computationally. Device for contactless determination of the temperature in preferably inaccessible locations, comprising - an element to be placed ( 1 . 10 ) of a ferromagnetic substance, - means ( 3 . 12 ) for generating a variable magnetic field - at least one sensor ( 4 . 11 for determining the size of the magnetic stray field of the ferromagnetic substance and an evaluation unit for determining the temperature of the element from the comparison of the size of the magnetic stray field of the ferromagnetic substance of the element resulting from the remanence magnetization of the magnetized ferromagnetic substance of the element 1 . 10 ) with predetermined or used element ( 1 . 10 ) determined magnetic stray field reference data. Device according to claim 14, characterized in that as an element ( 1 . 10 ) a small ball of ferromagnetic material is used. Apparatus according to claim 14, characterized in that are used as the ferromagnetic substance iron oxide, such as Fe ₃ O ₄ and γ-Fe ₂ O ₃ or mixtures thereof. Device according to claim 14, characterized in that as ferromagnetic substance titano-magnetite, d. H. Mixed oxides of iron oxide and titanium oxide, find use. Device according to claim 14, characterized in that as means ( 3 . 12 ) for generating a variable magnetic field one (or more switchable electromagnetic coils ( 3 . 6 . 12 ) Find use. Device according to claim 14, characterized in that as means ( 3 . 12 ) for generating a variable magnetic field eint or more each to be brought into the magnetization region of the element to be used magnets. Device according to claim 14, characterized in that as means ( 3 . 12 ) are used to generate a variable magnetic field, a magnetic field generating arrangement and in the area between this and the element placed on the location moving magnetic shield. Device according to claim 14, characterized in that the evaluation unit is a database to compare the size of the determined contains magnetic stray field with the stray field reference data. Device according to claim 14, characterized in that the evaluation unit for the comparison the size of the determined stray magnetic field with the stray field reference data one or more interfaces for data input and / or for connection to external data sources. Device according to claim 21 and / or 22, characterized in that the evaluation unit computational Funds for comparing the size of the determined magnetic stray field with the stray field reference data and for the evaluation and Output of the temperature of the element determined from this comparison contains. Use of the method according to one or more the claims 1 to 13 and the device according to one or more of claims 14 to 23 for temperature detection and control in tissue examinations. Use of the method according to one or more the claims 1 to 13 and the device according to one or more of claims 14 to 23 for temperature detection and control in or on buildings and especially concrete structures. Use of the method according to one or more of claims 1 to 13 and the Vor Direction according to one or more of claims 14 to 23 for monitoring the cold chain of refrigerated and frozen goods.