WELCOME

THE SPINTRONIC SCANNER FOR CANCER DETECTION

SREENATH K.SBSc ELECTRONICS E6CAS,MALLAPPALLY

CONTENTS INTRODUCTIONSPINTRONICSCANCER CELLSPROPERTIES OF SPINDETECTION OF CANCER CELLSPOLARIZED ELECTRON SOURCESPIN DETECTORSEXTERNAL MAGNETIC FIELDAPPLICATION OF SPINTRONICS IN MEDICAL FIELDCONCLUSIONREFERENCES

INTRODUCTION An emerging research field in physics focused on spin-

dependent phenomena applied to electronic devices.It is based on manipulation not only of the charge of

electrons, but also their spin, which enables them to perform new functions.

brings out an innovative idea of extending the hands of spintronics in MEDICAL FIELD, in the detection of cancer cells even when they are very few in number in the human body.

Study of the role played by electron spin in solid state physics, and possible devices that specifically exploit spin properties instead of or in addition to charge degrees of freedom.

An electron is just like a spinning sphere of charge. It has a quantity of angular momentum (its "spin") and

an associated magnetism.In an ambient magnetic field its energy depends on how

its spin vector is oriented.

SPINTRONICS

SPINTRONICSEvery electron exists in one of two states;spin-up and

spin-down.An electron can rotate either clockwise or

counterclockwise around its own axis with constant frequency.

Two spins can be "entangled" with each other, so that neither is distinctly up nor down, but a combination of the two possibilities.

CANCER CELLSsomatic cells which are grown into abnormal size,have

different electromagnetic pattern when compared to normal cells.

most cancers begin with abnormal cells growing out of control, forming a lump that's called a tumor.

the longer the tumor goes unnoticed, the greater the chance that the cancer has spread. This makes treatment more difficult.

CANCER CELLS Tumor developed in human body, is removed by

performing a surgery. Even if a single cell is present after the surgery, it would again develop into a tumor. In order to prevent this, an efficient method for detecting the cancer cells is required.

With Spintronics we introduce a new method for detecting the cancer cells after a surgery. This accurate detection of the existence of cancer cells at the beginning stage itself ensures the prevention of further development of the tumor.

PROPERTIES OF SPINThe spin of an electron has a great dependence over an

external magnetic field.Polarization of spin of electrons is possible so that the

spin of all electrons orient in a particular direction.The electron spin can be detected by using devices like

polarimeters.The electron spin can be controlled electrically just with

the application of few volts.

DETECTION OF CANCER CELLSThe following setup is used for the

detection of cancer cells in a human body:

 Polarized electron source

Magnetic field

Spin detector

Polarized electron source

A beam of electrons is said to be “polarized” if their spins point on average in a specific direction.

requirement:Photoemission from negative electron affinity GaAsChemi -ionization of optically pumped meta stable

HeliumAn optically pumped electron spin filter

Polarized electron sourceA spin filter is more efficient electron polarizer which uses an

ordinary electron source along with a gaseous layer of Rb.

Free electrons diffuse under the action of an electric field

through Rb vapour that has been spin polarized in optical

pumping.

Through spin exchange collisions with the Rb, the free electrons

become polarized and are extracted to form a beam.

SPIN DETECTORSThe spin polarization of the electron beam can be

analyzed by using:

Mott polarimeter

Compton polarimeter

Moller type polarimeter

SPIN DETECTORSTypical Mott polarimeters require electron energies of

~100 keV.

Mini Mott polarimeter uses energies of ~25 keV,

requiring a smaller overall design.

The Mini Mott polarimeter has three major sections: the

electron transport system, the target chamber, and the

detectors.

EXTERNAL MAGNETIC FIELDThe magnetic field is applied after the surgery has

undergone.

First, it is applied to an unaffected part of the body and

then to the surgery undergone part of the body.

The magnetic field could easily alter the polarization of

electrons.

APPLICATION OF SPINTRONICS IN MEDICAL FIELD.

EXPERIMENTAL SETUPMOTTPOLARIMETER OPTICALSPINFILTE

R

HUMAN BODY

PROCEDUREAfter surgery and the removal of the tumor, the patient is exposed to a strong magnetic field. Now the polarized electron beam is applied over the

unaffected part and spin orientation of electrons are determined using polarimeter.

Then the same polarized beam is targeted over the

affected part of the body and from the reflected beam, change in spin is determined.

APPLYING MAGNETIC FIELDWhen the magnetic field is applied to the unaffected

part of the human body, the normal somatic cells absorbs the magnetic energy and retains it.

SPIN ORIENTATION OF THE UNAFFECTED PART OF THE BODY:

DETERMINING THE SPIN ORIENTATIONWhen the electrons get incident on the cells the

magnetic energy absorbed by the cells alters the spin orientation of the electrons.

These electrons get reflected and it is detected by the Mott polarimeter.

The change in spin orientation of the electrons is measured as Sx.

APPLYING MAGNETIC FIELD The cancer cells which are present, if any, will absorb

more magnetic energy than the normal cells since they differ in their electromagnetic pattern

SPIN ORIENTATION OF SURGERY UNDERGONE PART OF THE BODY:

DETERMINING THE SPIN ORIENTATION Now an electron beam which is polarized is incident on

the surgery undergone part of the body. The magnetic energy absorbed by the cancer cell alter

the spin orientation of the electron beam.

DETERMINING THE SPIN ORIENTATION

Since cancer cells absorb more magnetic energy, the

change in orientation caused by them are also more.

If no cancer cells are present the amount of change is

equal to the previous case.

The change in spin is measured by the polarimeter as Sy.

INFERENCE

If Sx=Sy

If Sx not equals Sy

CONCLUSION The usage of electron spin in the cancer cell detection

provides way for the entry of spintronics in medical

field. The approach suggested in this paper acts as an

efficient way of cancer cell detection after surgery

thereby preventing the further growth of tumor cells.

REFERENCESWWW.PHYSICSWEB.COM

WWW.QUINON.COM

WWW.JLAB.ORG

WWW.EBAY.COM

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