27174560 bio magnetism btech seminar

8/8/2019 27174560 Bio Magnetism Btech Seminar

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BIOBIO- -MAGNETISMMAGNETISM


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OUTLINEOUTLINE

INTRODUCTIONINTRODUCTIONBIOMAGNETIC THERAPY BIOMAGNETIC THERAPY

INSTRUMENTATION OF BIOINSTRUMENTATION OF BIO- -MAGNETSMAGNETS TYPES OF SQUIDS TYPES OF SQUIDS WORKING WORKING APPLICATIONS OF SQUIDS APPLICATIONS OF SQUIDS

ADVANTAGES ADVANTAGESDISADVANTAGES OF MAGNETICDISADVANTAGES OF MAGNETICMEASUREMENTMEASUREMENT


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IntroductionIntroduction

BioBio--magnetism is a new field of research dealing withmagnetism is a new field of research dealing withthe measurement and interpretation of magnetic fieldsthe measurement and interpretation of magnetic fieldsproduced by organs or by magnetic contaminants of theproduced by organs or by magnetic contaminants of thebody body

Some examples are:Some examples are: The bio The bio--magnetic fields arising from ironmagnetic fields arising from iron--bearing bearing proteins in human liver.proteins in human liver.

Magnetic contaminants may be found in the lungs andMagnetic contaminants may be found in the lungs andstomachstomach


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BIOMAGNETIC THERAPY BIOMAGNETIC THERAPY

The healthy tissue produces a distinct negative, micro voltage. The healthy tissue produces a distinct negative, micro voltage. When trauma, stress or malfunction occurs, the potential changes When trauma, stress or malfunction occurs, the potential changesto a positively charged stateto a positively charged state ..

T The nervous relay system immediately transmits the relay to thehe nervous relay system immediately transmits the relay to thebrain, which floods the problem area with healing negativebrain, which floods the problem area with healing negativecharges to correct the chaotically charged areacharges to correct the chaotically charged area

The metabolism process in each cell is dependent on The metabolism process in each cell is dependent onbiopotential in this cellbiopotential in this cell

The negative field of a magnet is used to correctly stimulate & The negative field of a magnet is used to correctly stimulate &create the healthy cellular charge state of a strong negativecreate the healthy cellular charge state of a strong negativepotential. Hencepotential. Hence the need for properly designed biomagneticthe need for properly designed biomagneticfield.field.


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Current in the body is not like current through a wire.Current in the body is not like current through a wire.(A)(A)

It is expressed as current dipole (mAIt is expressed as current dipole (mA- -m)m) A current dipole consists of a source A current dipole consists of a sourceat the dendrite and a sink at the soma.at the dendrite and a sink at the soma.

The distance between source and sink The distance between source and sink determine he impact of current dipoledetermine he impact of current dipole

on the other dipole in the surrounding tissue.on the other dipole in the surrounding tissue. The total effect produces two current patterns of The total effect produces two current patterns of

opposite polarity, one outwardopposite polarity, one outwardand the other inward, hence theand the other inward, hence thename current dipole.name current dipole.


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INSTRUMENTATIONINSTRUMENTATION

Super Conductivity Quantum Interference DeviceSuper Conductivity Quantum Interference Device(SQUID) is a magnetometer used to measure extremely (SQUID) is a magnetometer used to measure extremely

weak magnetic field. weak magnetic field.

Threshold for SQUID: 10^ Threshold for SQUID: 10^- -14 T14 TMagnetic field of brain: 10^Magnetic field of brain: 10^--13 T13 TMagnetic field of earth: 2.5x10^Magnetic field of earth: 2.5x10^--88

SQUIDSQUID is an assembly of is an assembly of Josephson junctions within a Josephson junctions within asuperconducting ring.superconducting ring.


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The Josephson junction is composed of two The Josephson junction is composed of twosuperconductors separated by a thinsuperconductors separated by a thin

insulating layer.insulating layer.

Electrons can tunnel through the insulator. HenceElectrons can tunnel through the insulator. Hencecurrent crosses the junction across superconductor despitecurrent crosses the junction across superconductor despite

insulator. This is Josephson Effect.insulator. This is Josephson Effect.

There are two main types of SQUID There are two main types of SQUID

(1)(1) Direct current (DC)Direct current (DC) Two Josephson Junction used Two Josephson Junction used(2) Radio Frequency (RF)(2) Radio Frequency (RF)-- One Josephson Junction usedOne Josephson Junction used


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D C SQUI D D C SQUI D Phase changes with changing Phase changes with changing magnetic field.magnetic field.

So does the super currentSo does the super currentaround the ring and thereby around the ring and thereby voltage. voltage. The change in flux crossing The change in flux crossing across the ring is quantized.across the ring is quantized.

The quanta of flux is given The quanta of flux is givenby by


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RF SQUI D SRF SQUI D S

Uses only one Josephson junction .Uses only one Josephson junction .Less sensitive compared to DC SQUIDSLess sensitive compared to DC SQUIDS

Widely used due to less cost Widely used due to less cost

The RF SQUID is coupled to a resonant tank circuit . As the The RF SQUID is coupled to a resonant tank circuit . As theSQUID operates the effective inductance of the tank circuitSQUID operates the effective inductance of the tank circuitchanges and thereby resonant frequency changes.changes and thereby resonant frequency changes.Output voltage is sinusoidal with linear variation in flux.Output voltage is sinusoidal with linear variation in flux.


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Structure of SQUI DsStructure of SQUI Ds


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APPLICATIONS OF SQUI D S APPLICATIONS OF SQUI D S

MEASUREMENT OF IRON IN LIVER MEASUREMENT OF IRON IN LIVER The liver is a major site for iron which is in The liver is a major site for iron which is in

the form of ferrinite and hemosiderin proteinthe form of ferrinite and hemosiderin protein which are paramagnetic which are paramagneticPARTICLES IN LUNGSPARTICLES IN LUNGS

Well Well--known examples of such particlesknown examples of such particlesare asbestos fibers, coal dustare asbestos fibers, coal dustand metal aerosols.and metal aerosols.


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ME D ICAL IMAGINGME D ICAL IMAGING

Computerized Tomography (CT)Computerized Tomography (CT)

Magnetic Resonance Imaging (MRI)Magnetic Resonance Imaging (MRI)Positron Emission Tomography (PET)Positron Emission Tomography (PET)


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MAGNETOENCEPHALOGRAPHY (MEG)MAGNETOENCEPHALOGRAPHY (MEG)Measures the magnetic fields produced in the brain by ionicMeasures the magnetic fields produced in the brain by ionic

current flow arising from neural activity.current flow arising from neural activity.

COMPARISION OF MEG, MRI & PETCOMPARISION OF MEG, MRI & PET


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MAGNETOCARDIOGRAPH (MCG)MAGNETOCARDIOGRAPH (MCG)Used for heart monitoring.Used for heart monitoring.

Heart produces a rhythmically synchronizedsignal. This signal is described by means of acurrent dipole.

SQUIDS pick up the magnetic signal.Signal is then amplified and sampled and thenfed to processor


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D ISA DV ANTAGES OFD ISA DV ANTAGES OFMAGNETIC MEASUREMENTMAGNETIC MEASUREMENT

Environmental noiseEnvironmental noiseMost effective solution is a magnetically shielding room (MSR).Most effective solution is a magnetically shielding room (MSR).Magnetic shielding: Mu metalMagnetic shielding: Mu metal

(high permeability alloy)(high permeability alloy)Eddy current and RF shielding:Eddy current and RF shielding:aluminum (high conductivity)aluminum (high conductivity)


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FUTURE SCOPEFUTURE SCOPE

A new program to image cancer and tumors A new program to image cancer and tumors with SQUID sensor arrays and super with SQUID sensor arrays and superparamagnetic nano particles is currently paramagnetic nano particles is currently under development.under development.Biomagnetism also have a good diagnostic value.Biomagnetism also have a good diagnostic value.


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REFERENCESREFERENCES

I.P.Wiksow, Jr; SQUID magnetometers for Biomagnetism andI.P.Wiksow, Jr; SQUID magnetometers for Biomagnetism andNondestructive Testing: Important Questions and IntialNondestructive Testing: Important Questions and Intial

Answers. Answers. IEEE Transactions on Applied Super Conductivity IEEE Transactions on Applied Super Conductivity Vol 5, No:2,June1998 Vol 5, No:2,June1998Handbook of Biomedical Instrumentation, R.S.KhandpurHandbook of Biomedical Instrumentation, R.S.Khandpur

www.biomagnetism.com www.biomagnetism.com


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THANK YOU THANK YOU

27174560 bio magnetism btech seminar

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