What do Physicists do in REAL LIFE
M.KUMARASAMY COLLEGE OF ENGINEERING
2/15/2015EMF11EMFMEDICAL APPLICATION OF ELECTRO MAGNETIC FIELD
2/15/201522EMFWhat do Physicists do in REAL LIFE
Many work with doctors in the field of Medicine
2/15/20153Doctors often need to look inside our bodies without cutting them open.Some you may have heard ofX-rays..NMR..MRI scansAnd new ones you may not have heard of yet.PET scans..MEG"Medical Physicists"are essential in the development of many scanning technologies2/15/201544EMF
Here is your chance toFind out the basics of how these scans work See how important electro magnetic field in modern medicine.2/15/201555EMFELECTRO MAGNETICWAVES
2/15/20156 X-raysVery little ordinary light can pass through skin. Its either absorbed at the surface or reflected back.. To see inside we need a kind of light with more energy
SkinOrdinary LightX rays2/15/201577EMF Taking X raysThe patient is placed in front of a source of X-rays.X ray TubeA photo graphic plate is placed on the other side of the patientMost of the X rays pass through the patients body.2/15/20158X-rays are also partly absorbed by some tissues in body this creates a more subtle picture. SOFT TISSUEboneSoft tissuePhotographicplate2/15/201599EMF X-RAYS
2/15/2015.10Advantage of X raysX-rays are easy to produceX-rays machines are relatively cheapX-rays are used to diagnose broken bones, dislocated joints etc..
2/15/20151111EMFDisadvantage of X-raysIn large doses X rays can harmful to health.
Imaging of soft tissues and organs is not always very detailed.
2/15/20151212EMF MRI What do the letters stand for?M.. MagneticR ResonanceI. Imaging
MRI scanners do not use X rays.
2/15/20151313EMFWith the patient safety check complete the scan can begin The part of the body to be scanned is placed in the centre of the primary magnetXThis field causes the Hydrogen nuclei in the patients body to line up with the field2/15/20151414EMFThe patient is placed on a bed and then moved into a large hollow tube.
The tube contains a very powerful magnet. Using an MRI Scanner2/15/2015EMF1515EMFIt took physicists over 40 years to turn their discovery of nuclear magnets into images of the human body.
2/15/20151616EMFView an MRI scan from any angle..
2/15/20151717EMFADVANTAGESDo not involve exposure to radiations.Ability to image without the use of ionising radiations.Scanning and detection of abnormalities in soft tissues.
2/15/201518DISADVANTAGESVery expensive (1 million )While processing creates so much of noise.It is done in enclosed space.Less spatial resolution than COMPUTED TOMOGRAPHY.
2/15/201519 PET (positron emission tomography)snapshot images are usefulbut doctors sometimes need real time pictures of how parts of your body are functioninge.g. How your heart is functioning.
2/15/20152020EMFPET SCANNERS LOOK LIKE CT SCANNERS -NO X RAY TUBE.-The ring is surrounded by Gamma Ray detectors
2/15/20152121EMF PET scan patients are injected with a specially created substance called a RADIOTRACER.Usually a Radioactive type of glucose.
The radiotracer is a source of positrons which leads to the production of gamma raysINSIDE THE PATIENTS BODY!2/15/20152222EMFThe radiotracer concentrates itself in certain tissue types
This glucose type radiotracer has concentrated itself in high glucose using cells like the brain, kidneys and cancer cells.2/15/20152323EMF PET ScansThe biggest cost is in the production of RADIOTRACER
The hospital needs to have access to a CYCLOTRON
2/15/20152424EMFADVANTAGESUsed for diagnosis of many diseases.At small movement it does not ruin the scan.To show blood flow, oxygen and glucose metabolism in the tissue.
2/15/201525DISADVANTAGESScans works by injecting a patient with radionuclide.Radioactivity decays rapidly.Images are of substantially lower.
2/15/201526 MEG (magnetoencephalography)
It doesnt put anything into a patients body.
It just measures something that is already there
No X rays/Strong Magnetic Fields/Radio waves/Radiotracers
2/15/20152727EMFYour body is full of tiny electric currents!These tiny currents produce tiny magnetic fieldsMEG is able to measure some of these.
2/15/20152828EMFADVANTAGESMeasure activity of the brain extreme quickly.Temporal specificityEffective diagnostic tool for evaluating brain function.Easy to use
2/15/201529 DISADVANTAGESVery invasiveMore expensiveCannot detect activity of the cellCannot be used with the patients who are claustrophobic.
2/15/201530NMR(NUCLEAR MAGNETIC RESONANCE)Used for magnetic resonance imaging for medical diagnosis and magnetic resonance microscopy in research setting.
Biochemical information can also be achieved from LIVING TISSUE.
EX: HUMAN BRAIN TUMOR2/15/201531 NMR process NMR scan the narrow table moves the patient through a tunnel like structure create a magnetic field through which radio waves are sent , creating a 3-D image of the internal structure.
2/15/201532 NMR SCANNERNMR SCANNERalso utilisedin low field NMR.
Its effectiveness can be Improved byHYPERPOLARISATIONand using 2D,3D Techniques.
2/15/2015133NMR HAHN ECHO DECAY EXPERIMENT
Does not require contrast media,so no anaphy lactic reaction.Better accuracy in localisation of etiologyNo complications like pancreatitis,bleeding etc..Non invasive
2/15/201535 DISADVANTAGES Imaging compared with other modalities is intrinsic insesitivity of the method.Very expensiveTime consumingSpectra take long time to interpret.
2/15/201536ELECTRO MAGNETIC BLOOD FLOW METERWorks on the principle of FARADAYS LAW OF ELECTRO MAGNETIC INDUCTION.Used to measure the blood flowFor this the diameter of blood vessel is outlined by the TRANSDUCER IN THE RADIOGRAM
2/15/2015EMF37ELECTRO MAGNETIC BLOOD FLOW METERIt is used during the vascular surgery to measure the quantity of blood passing through the vessel or graft before during or after surgery.
2/15/201538VARIOUS METHODS USED FOR ASSESSMENTObservation and palpation of pulses Intra-arterial pressure measurements with careful attention to the presence of GRADIENTSArteriography
2/15/201539 ADVANTAGESMeasurement of flow and volume of blood.During arterial reconstructionSuperior mesenteric artery reconstruction
2/15/2015EMF40 DISADVANTAGESSome times magnetic fields are not uniform
Wall of flow tube is conductive
Flow is axially non-symmetrical