Biomagnetism is a science in which magnetic fields produced by organs or by magnetic contaminants of the body are studied. The science of Biomagnetism applies a technology that was originally developed for the measurement of extremely small magnetic field in physics. Health is determined by the electromagnetic vitality of the cells to maintain the perfect chemical balance. Properly designed bio-magnetic field can dynamically manipulate the electrical charge of the cellular tissue back to a normal healthy condition thereby return to health. The application of Biomagnetism is very wide. It can detect storage of iron in liver, particles in lungs, brain studies, heart functions etc.
Biomagnetism is a combination of two sciences; Physics and Biology. It is the science where specifically designed magnets and their energy fields are used to affect the living system- the human body or what is called the Body electric. There are some basic physical laws that come into play with the body electric. The body electric is the energy flow found in the human body. This energy flow is the collective result of minute electrical currents and cellular charge values that runs the body and all its function. Biomagnetism can change and elevate the electrical currents and charges thereby increasing the efficient of the bodyâ„¢s functional metabolism.
A new field of scientific research called Biomagnetism was evolved after the major discovering of magnetic field associated with the flow of electric current in the human body. Biomagnetism deals with the study of magnetic contaminants of the body. The science of Biomagnetism applies a technology that was originally developed for the measurement of extremely small magnetic field in physics.
In Biomagnetism, magnetism fields produced by organs or by magnetic contaminants of the body are studied. The example of the fields arising from iron-bearing proteins in human liver. Magnetic particles may be found in the lungs and stomach where these are commonly introduced by environmental exposures particularly for workers in industries dealing with iron or steel. Biomagnetism is a science and should be taken seriously. When proper protocols are followed Biomagnets can help the body heal itself of even chronic and long term conditions.
Biomagnetic Therapy finds curing in person suffering from carpal tunnel, muscle tension etc or possibly someone who needs a good nights sleep or just wants to increase his or her general vitality.
Â¢ Magnetic therapy has been used for over 5000 years to treat many common health issues and some that are not so common
Â¢ Known as Iodestones, the Chinese first used the power of this magnetic stone to help heal disease over 5000 years ago.
Â¢ Cleopatra used this as a beauty aid.
Â¢ Paraclesus, a scientific in the late 1400â„¢s used them successfully to treat the cause of seizures and many other illnesses that at a time, had no known cures.
Â¢ Today Biomagnetic therapy is used worldwide to treat broken bones, conquer pain, relieve carpel tunnel, arthritics, increase vitality and help itself from even chronic disease.
The negative and positive pole techniques on the body are critical for successful Biomagnetic treatment. When used properly, Biomagnets are safe have no known side effects. Biomagnets help to regulate the bodyâ„¢s natural electrical current. They are safe, non invasive therapy that will help your body to do what the body wants to do naturally- relative pain and heal itself.
Researchers through the years have identified that the healthy cell tissue quantitatively gives off a distinct high- negative, micro voltage charge (potential). When trauma, stress or malfunction occurs, the cell changes from its healthy strong negative potential, or in extreme cases changes to a positively charged state. When this occurs the nerve relay system immediately transmits the relay to the brain, which floods the problem area with healing negative charges to correct the chaotically charged cellular orientations.
Health is determined by the electromagnetic vitality of the cells to maintain the perfect chemical balance. Cells transfer necessary elements and spent energy wasted through various channels by little electromagnets. Proper electrical vitality of the cell creates the natural DNA computers that arrange all the essential elements to properly organize and metabolize correctly. In the inverse the weak negatively charged or wrong electrical climate slows and / or shuts down the correction metabolism process and chemical balance.
The negative field of a magnet is used most often to correctly stimulate and recognize the electron (spin) charge which results in creating the healthy cellular charge state of a strong negative potential. The negative field is used in most treatments to help the body heal. When a cells electrical charge is elevated from its stressed, improperly charged state to a highly- charged negative state, the cells natural ionic tones and suddenly able to function properly and correctly metabolize all the necessary micronutrients. The primary point is that the properly designed Biomagnetic field can dynamically manipulate the electrical charge of the cellular tissue back to a normal, healthy condition- thereby return to health.
A physician named Mesmer claimed that an invisible fluid permeates (passes through the pores of) all objects in the universe including human body. He also claimed that our body contains poles like a magnet which when improperly aligned; prevent the flow of the fluid and the illness
CURRENTS AND FIELDS
We assume positively charged ions within the body to move in the orientation of arrow along a short narrow path confined by the cell membrane. Any net movement of charge from one area is the electric current. The field becomes weaker as the distance increases from the arrow. Such a current segment is known as current dipole. The current dipole has a strength given by the product of the current and length of the path. The total current pattern associated with a current dipole situated within a conducting medium like human body is shown in figure1.
What is a current dipole
The movement of positive charge in a current dipole produces a build- up of positive charge at the head of the arrow .The outward electric field from this charge drive ions in the surrounding medium to form an outward spreading pattern of current. Similarly at the tail of the arrow, the removal of the positive charge causes an inward flow of current. The total effect produces two current patterns of opposite polarity, one outward and the other inward, hence the name Ëœcurrent dipoleâ„¢.
Depolarization and Repolarization of cells results in currents with in the human body. And these currents give rise to Biomagnetic field. Figure2 shows the magnetic fields produced by a current dipole.
Figure 2: Magnetic field produced by a current dipole
DIPOLE THEORY IN BIOMAGNETISM
Since an active tissue is electronegative with respect to an inactive or recovered area, boundary exists that is characterized by an array of positive and negative charges. The boundary between active and inactive tissues can be represented by a dipole, and because tissues and fluids can conduct current, potential fields will be established. Figure3 illustrates the dipole theory in Biomagnetism
DETECTION OF BIOMAGNETIC FIELD
Magnetic field arises from the currents in the human body. When a person touches a table with a finger, the magnetic response in the brain is observed as the sensory center of the brain that is devoted to tactile the response of that region. The magnetic field is influenced by intracellular axial current that are confined to the regions of discharging cortex in brain. The most sensitive instrument for measuring magnetic fields is based on the Super Conductivity Quantum Interference Device (SQUIDS). Figure4 shows a SQUID control system.
The most sensitive instrument for measuring magnetic fields is based on the superconductivity quantum interference device SQUID. A SQUID is a mechanism used to measure extremely weak signals, such as subtle changes in the human bodyâ„¢s electromagnetic energy field. Using a device called a Josephsons junction, a SQUID can detect a change of energy as much as 100 billion times weaker than the electromagnetic energy.
Theory of Josephson junction
The Josephson junction is composed of two superconductors separated by a thin insulating layer. The junction is connected in a circuit with an external voltage applied across a resistor, the current; I and the voltage drop, V across the junction can be measured.
Super conductivity and Super conductors
When certain substances are cooled below a critical temperature, the electrical temperature, the electrical resistance becomes very small, effectively vanishing. The superconductor is not a perfect conductor, but a perfect diamagnetic material with zero electrical resistance. This is known as Meissner Effect. The high sensitivity of SQUID is made possible by superconductivity.
What is SQUID magnetometer
Superconducting Quantum Interference Device can detect magnetic fields generated by electrical activity in smooth muscle. The SQUID MAGNETOMETER, a popular and extremely useful device, uses the interaction between magnetic flux and josephson junction.
How does a SQUID work
The SQUID has as its active elements one or more josephson junctions. A josephson junction is a weak link between two superconductors that can support supercurrent below a critical value. The special properties the josephson junction cause the impedance of the SQUID loop to be a periodic function of the magnetic flux threading the SQUID so that a modulation signal applied to the bias current is used with a lock in detector to measure the impedance and to linearism the voltage to flux relationship. The net result is that a SQUID functions as a flux to voltage converter with unrivaled energy sensitivity.Figure5 shows the structure of SQUID
The SQUID is located inside a small cylindrical, superconducting magnetic shield in the middle of liquid helium dewar as shown in fig: 5 This minimizes helium evaporation due to excessive heating. The special geometry of the detection coil is less sensitive to the magnetic field from distant sources. The coil is mounted at the bottom of the dewar, close to the head. The rest of the hardware is designed to minimize helium boil off, eliminate RF interference, and to not contribute Johnson noise or distort any external ac fields.
TYPES OF SQUIDS
Based on the applied bias there are two types
1. AC or RF
2. DC SQUIDS
DC SQUIDS are easier to analyze and understand, but until the past decade, AC SQUIDS were more popular as they were easier to construct and use.
The main part of a dc SQUID is the dual junction superconducting loop as shown in figure6
I0-critical supercurrent carried by the loop
1&2 -phase difference across the junction
The SQUID loop has an inductance, L, which means that any change in the magnetic flux through the loop will result in a current being induced to
produce opposing flux. The induced current is the shielding current, is, and circulates around the loop. A dc SQUID is designed such that when a dc current is sent to one end of the device, the current divides into two parts to take different routes to the other end. At this end, interference takes place between the two waves. When a magnetic field is applied to the region separating the paths, it accelerates the flow of electrons in one path and retards the electrons in other path. Because of this the interference conditions are changed. This can be detected by incorporating a wave link in each of the paths. This effect is very sensitive to the presence of magnetic field and it is for this reason that SQUIDS are useful as good magnetic sensors.
The figure7 shows the arrangement of dc SQUID system
Since the signal out of a SQUID is compared with the magnitude of normal electronic signals, amplification is necessary. The dc SQUID is supplied with a constant current. The flux through the loop is modulated by a 100 KHz flux from the feedback coil. The greater magnitude would mask any signal that one would wish to detect. Lock in amplifier amplifies the difference between the SQUID loopâ„¢s signal and the 100 KHz signal and this is fed back to the feedback coil, the feedback coil adjusts until the feedback flux cancels the input flux. The SQUID loop has a small inductance, so flux is usually collected using a large input coil, and mutually induced into the SQUID loop via another coil.
MORE ABOUT SQUIDS
SQUIDS have been fabricated from pure Nb and from Pb alloys containing about 10%Au or In. Pure lead is not used because of its instability in thermal cycling. The Nb-Pb alloy structure is preferred because it has better properties than all Pb or all Nb alloy structure. It has extra hardness and high tensile strength.
APPLICATIONS OF SQUIDS
SQUIDS have been used for a variety of testing purposes that demand extreme sensitivity; including engineering, medical and geological equipment. A SQUID is capable of detecting a change in magnetic field without any extra equipment.
SQUIDS IN BIOMAGNETISM
The measurements of biologically produced magnetic fields were unknown before the invention of SQUIDS. There are many magnetic fields which have been measured, ranging from the susceptibility of tissue to applied magnetic fields to ionic healing currents and those associated with neural or muscle activity
By far the largest area of study within Biomagnetism is brain imaging. Most existing non invasive brain imaging methods such as Computerized Tomography (CT), Magnetic Resonance Imaging (MRI) and Positron Emission Tomography (PET), measure the distribution of some kind of matter and are therefore primarily a measure of structure.
It utilizes SQUIDS to measure the magnetic fields produced in the brain by ionic current flow arising from neural activity. Brain generates rhythmical potentials which originate in the individual neurons of the brain. The potentials get summated as millions of cells developing synchronously and appear as a surface waveform. Current MEG techniques have spatial resolutions of 1-5mm but the time resolution\ions is between 1-5ms allowing real time imaging. This real time imaging allows research into epileptic seizures and other psychological disorders.figure8 shows the comparison of the spatial and time resolution of MEG, MRI and PET imaging.
SQUIDS are used in popularly for heart monitoring. The figure9 shows the MCG measurement system.
Figure 9.2: Schematic diagram of magneto cardiogram measurement system
Heart produces a rhythmically synchronized signal. This signal is described by means of a current dipole. SQUIDS pick up the magnetic signal. Signal is then amplified and sampled through an RF amplifier. Controller interconnects the magnetic signal arising from the heart to the processor via A\D converter. Processor is connected to printers and to display monitors.
ADVANTAGES OF MAGNETIC MEASUREMENT
Magnetic measurement of nerve function can be made directly in the conducting fluid.
Â¢ The use of split torrid allows measurement without puncture or intrusive contact with nerve axon.
Measures the current density directly and allows determination of current profiles (MCG).
MCG exceeds the diagnostic value of ECG.
Good spatial and temporal resolution.
Â¢ Magnetic field is less than distorted by tissues than the electric potential.
Â¢ Localization is more exact especially for multiple dipole sources.
Functional diagnostic information(MRI,CT,PET)
DISADVANTAGES OF MAGNETIC MEASUREMENT
Biomagnetism fields are much weaker than typical fields in our environment such as those produced by motor vehicles, elevators etc. The principle challenge in field measurement is from environmental noise. The most straight forward solution for shielding the magnetic noise is a magnetically shielding room (MSR).Figure10 shows an MSR
MAGNETICALLY SHEILDED ROOM
Biomagnetic fields are almost a billion times weaker than the earthâ„¢s geomagnetic field, thereby requiring a high performance MSR to shield out the broad spectrum of everyday RF and magnetic interference.
FEATURES AND BENEFITS
Optimum shielding effectiveness>=80db from 10Khz-1Mhz
MSR is constructed of several high grade materials such as aluminium, Mu metal and copper. It has demountable construction.
Magnetic shielding: Mu metal (high permeability alloy)
Eddy current and RF shielding: aluminium (high conductivity)
WALL: Acoustic damping
FLOORS: Vibration damping & antistatic
WEIGHT: Approximately 3400kg
MSR allows imaging equipment such as MEG system to be able to detect weak fields in the presence of much stronger environmental magnetic and RF fields. The figure11 shows the schematic view of an MSR. As shown in the graph we can see that outside the MSR, there is high field noise and inside the MSR it is very much reduced.
Â¢ Storage of iron in the liver
Â¢ Particles in lungs
Â¢ Brain studies
Â¢ Heart functions
STORAGE OF IRON IN LIVER
An important application of Biomagnetism in medicine is measurement of iron concentration in liver. The liver is a major site for iron which is in the form of ferrinite and hemosiderin proteins which are paramagnetic. In earlier days, this was measured by chemical analysis in which a tissue is removed from the liver through biopsy which was painful and unsafe.
To measure the iron concentration, the basic idea is to apply a field to the region of the liver and measure the field response produced by molecules in the body tissues. The response of the tissue in comparison with the strength of applied field is called magnetic susceptibility of the tissue. Hence to determine iron concentration only the susceptibility of the liver needs to be measured.
PARTICLES IN LUNGS
Another application of Biomagnetism is the measure of the magnetic field from magnetic particles in the lungs. Well-known examples of such particles are asbestos fibers, coal dust and metal aerosols.
To detect the presence of magnetic particles, a strong magnetic field is applied over the region of lungs. The magnetic field is detected by removing the applied field and bringing a sensitive detector near the chest. The magnetic particle become magnetized in that common direction and produces a magnetic field. Then a scan of the detector over the chest gives the information about the amount and distribution of magnetic field.
Brain research is the most rapidly growing application of biomagnetism. Neuro magnetic measurements can localize active regions of the brain whether other approaches have failed. Local paroxysmal discharges lead to the generation of magnetic field in the skull. These fields are calculated by means of neuromagnetic techniques.
Magnetic techniques provide a direct measure of brain activity. But it has a limitation that radial current sources are magnetically silent. Thus when a complete specification of source is required, it is better to use both magnetic and electric techniques.
Mapping of the magnetic field outside the chest of the subject describes the spatial and temporal behavior of MCG. These maps were first measured by Cohen and Chandler in1969. This measurement instrument was induction coil magnetometer.
In 1975 flexible magnetocardiographic measurement grid was introduced in 1975. The plannar anterior MCG measurement grid was introduced thereafter. The MCG has diagnostic capabilities comparable to that of the ECG and in several studies, it has been reported to even exceed the diagnostic value of ECG.
Based on the double relaxation oscillator SQUIDS (DROS) a 3-axis vector magnetometer system has been constructed for magneto cardiogram and mapping of MCG.
A new program to image cancer and tumors in â€œvivo with SQUID sensor arrays and super paramagnetic nano particles is currently under development.
Biomagnetism is a boon for medicine. Biomagnetism fields result from currents or magnetization of biological tissues. Biomagnetism helps in brain study, measurement of iron concentration in liver, measurement of magnetic particles in lungs and study of heart functions.
The application of magnetic fields to human and animals is classified as not being harmful. This is not harmful status resulted from a pre-market toxicity study with MRI procedures using longer periods of exposures. A static magnetic field is an energy field is an electric field by virtue of the movements of electrons in the static electric field. This fact of the magnetic field is used in industry with predictable results and can also be used in magnetic therapy with the same predictable results.
Magnetic therapy is very efficient and have better results. Biomagnetism also have a good diagnostic value.
To conclude Biomagnetism is a boon for medicine.
1. I.P.Wiksow, Jr; SQUID magnetometers for Biomagnetism and Nondestructive Testing: Important Questions and Intial Answers. â€œIEEE Transactions on Applied Super Conductivity Vol 5, No:2, June1998
6. Measurement Science and Technology by H.J.Wieringa & H.Rogalla
7. Electronics for you.2000 July
8. Handbook of Biomedical Instrumentation, R.S.Khandpur
I extend my sincere gratitude towards Prof . P.Sukumaran Head of Department for giving us his invaluable knowledge and wonderful technical guidance
I express my thanks to Mr. Muhammed kutty our group tutor and also to our staff advisor Ms. Biji Paul and Mr. Santhosh Kumar for their kind co-operation and guidance for preparing and presenting this seminars.
I also thank all the other faculty members of AEI department and my friends for their help and support.
2. BIOMAGNETIC THERAPY
4. BIOMAGNETIC FIELDS
7. TYPES OF SQUIDS
8. MORE ABOUT SQUIDS
9. APPLICATIONS OF SQUIDS
10. OTHER APPLICATIONS
11. ADVANTAGES OF MAGNETIC MEASUREMENT
12. DISADVANTAGES OF MAGNETIC MEASUREMENT
14. FUTURE SCOPE