historical perspective of radiology

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Historical perspectives Of Radiology Dr Deebika Vinothprabu

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Page 1: historical perspective of radiology

Historical perspectives OfRadiology

Dr Deebika Vinothprabu

Dr Deebika vinothprabu

Page 2: historical perspective of radiology

History of radiology

1895 – Wilhelm Conrad Roentgen detects x rays & take first x ray

1896 – Antoine Henri Becquerel discovers radioactivity

1896 – Thomas Alva Edison invents first commercially available fluoroscope

1913 – Albert Salmon – mammography

1927 – Egas Moniz – cerebral angiography

1950 – David e.kuhl invents PET

Page 3: historical perspective of radiology

• 1953 – Sven Ivar Seldinger – seldinger technique

• 1957 – Ian Donald – ultrasound

• 1964 – Charles Dotter – image guided intervention

• 1972 – Godfrey Hounsfield & Allan m.Conmarck – CT

• 1977 – Raymond Vahan Damadian – mri scanner

Page 4: historical perspective of radiology

History of X rays

Discovery of x rays was the beginning of revolutionary change German physicist WILHELM CONRAD RONTGEN discovers x rays – 1895

Nobel prize in physics in 1901

In 2004, international union of pure and applied chemistry named element 111 as ROENTGENIUM(radio active element)

Page 5: historical perspective of radiology

• In early november he was investigating external effects of various vacuum tubes.

• While doing experiments with vacuum tubes,he added aluminium window to permit cathode rays to exit & a cardboard covering added to protect aluminium from damage by electrostatic field that is necessary to produce cathode rays

• Roentgen observed invisible rays caused fluorescent effect on carboard screen painted with barium platinocyanide

Page 6: historical perspective of radiology

• He investigated various properties of rays which he called ‘X RAYS’

• He took the very first picture using x rays of his wife Anna berthas’s hand

Page 7: historical perspective of radiology

X RAYS part of electromagnetic spectrum

Wide range of Wavelength

Deeply penetrating,highly destructive shorter wavelength – HARD X RAYS

Longer wavelength,lesser penetrating power – SOFT X RAYS

Soft xrays – used in medical & dental diagnosis

Ionising radiation

Carries high energy & deposits a part of it within the body it passes

Cause biological effects

Page 8: historical perspective of radiology

X ray tubes Crookes tube

-invented by william crookes

-first used x ray tubes -used untill 1920

-generate electrons by ionization of residual air in the tube

-used an aluminium cathode, platinum anode

-unreliable as residual air in tube absorbed by walls

Page 9: historical perspective of radiology

Coolidge tube

• Improved by william coolidge 1913• Most widely used• Electrons produced by thermionic effect• Tungsten filament(cathode) heated by electric current• High voltage potential between cathode & anode• Electrons accelerated hit anode

Page 10: historical perspective of radiology

X-Ray tube

Filament

Rotor

Vacuum envelopeAnode

Cathode

Page 11: historical perspective of radiology

X rays produced due to sudden deceleration of fast moving electrons when they collide & interact with target anode99% electron energy converted to heat and 1% into x ray productionCathode(tungsten filament) is the negative terminal of x ray tubeWhen current is flowing through it filament gets heated and start emitting electrons by process called thermionic emissionHigh voltage applied between cathode and anode

Anode(tungsten disc) is the positive terminal.fast moving electron interact with anode in 3 ways1)Interaction with K-shell electron – charecteristic x rays2)Interaction with nucleus – bremsstrahlung radiation3)Interaction with outer shell electron – line spectrum

Page 12: historical perspective of radiology

In early 1896 in the wave of excitement following Roentgen’s discovery of x rays, Antoine Henri Becquerel ,french physicist thought that phosphorescent materials such as Uranium salts emit penetrating x ray like radiation when illuminated by sunlight

Discoverer of radioactivity1903 – received nobel prize in physics along with Marie Curie & Pierre Curie

Page 13: historical perspective of radiology

Fluoroscopy

• First crude fluoroscope created within months after x ray discovery

• Use of x rays to produce a moving image of internal structure of patient

• Fluoroscopy uses continuous x ray beam that is passed over area of interest

• Frequently used to evaluate GI tract,kidney function etc

Page 14: historical perspective of radiology

Computerised radiography

• Similar to conventional radiography except that in place of the flim to create the image,an imaging plate made of photostimulable phosphor used

• Imaging plate is housed in a special cassette and placed under the object and xray exposure made

• Imaging plate is run through a special laser scanner that reads the image

Page 15: historical perspective of radiology

Digital x ray

• X ray sensors(digital image capture device)are used instead of traditional photographic film

• Time efficiency

• Ability to digitally transfer & enhances image

• Less radiation

• Immediate image preview & availability

• Eliminates costly film processing

Page 16: historical perspective of radiology
Page 17: historical perspective of radiology

Mammogram

1949 – Raul Leborgne,radiologists introduced compression technique

Late 50’s –Robert L.Egan,radiologists introduces a new technique using fine-grain intensifying screen & industrial film for clearer images

MID 60’s – gain acceptance as screening tool

german surgeon Albert Salmon attempts to visualize cancer of breast through radiograph1913

1949

Late 50’s

MID 60’s

Page 18: historical perspective of radiology

– modern day film mammogram invented 1969

1993

2000

2011

– mammogram recommended as screening tool by American Cancer Society

– FDA approves first digital mammography system

– FDA approves Hologic’s 3D mammography technology(breast tomosynthesis),proven clinically superior to digital mammography

Page 19: historical perspective of radiology

Ultrasonogram

• Ian Donald – first diagnostic application of usg – 1956,one dimentional A mod (amplitude mode)

• 1963 – B mode(brightness mode)two dimentional devices constructed

• Turning point in application of ultrasound in medicine

• In mid seventies (kossoff garrett)introduction of real time ultrasound scanner

• Decade later,doppler effect enabled visualization of blood circulation

Page 20: historical perspective of radiology

• Ultrasound refers to sound waves with frequency too high for humans to hear

• Images made by sending a pulse of ultrasound into tissue using ultrasound transducer

• Sound reflected fron parts of tissue recorded as image

Page 21: historical perspective of radiology

Modes

A-MODE : -simplest type -single transducer scans a line through the body with echoes plotted on screens function of depth -therapeutic ultrasound for tumor or calculus for pinpoint focus of destructive wave energy

B MODE : Linear array of transducers scan a plane that viewed as two – dimentional image on screen

Page 22: historical perspective of radiology

M – MODE : M for motion rapid sequence of B mode scans images follow each other in sequences ,enable see & measure range of motion commonly used to measure cardiac dimensions & ejection fraction

DOPPLER MODE : In measuring & visualizing blood flow

Page 23: historical perspective of radiology

Doppler effect

• Christian Andreas Doppler(1803-1853),austrian physicist & mathemetician formulated his theory in 1842

• Observed change in the frequency of transmitted waves when relative motion exists between the source of wave & an observer

Page 24: historical perspective of radiology

• First medical applications of doppler sonography initiated during late 1950’s

• First pulsed-wave doppler equipment developed by Donald Baker,Dennis Watkins & John Reid worked on this project in 1966 produced one of first pulsed Doppler devices

Page 25: historical perspective of radiology

Convex 3.5 MHzFor abdominal and OB/GYN studies

Micro-convex: 6.5MHzFor transvaginal andtransrectal studies

Ultrasoundmachine

Ultrasound examination

Page 26: historical perspective of radiology

3D USG

Sound waves sent at different angles

Returning echoes processed by sophisticated computer resulting in three dimentional volume image of fetus’s surface

First developed by Olaf Von Ramm 1987 OBS - Timing of 3d scan between 26 to 30wks

Page 27: historical perspective of radiology

4D USG

• Similar to 3D usg with the difference associated with time

4D allows 3 dimentional picture in real time

it is reffered to 4D when baby is moving in 3D

Page 28: historical perspective of radiology

Elastography

Maps the elastic properties of soft tissueGives diagnostic information about disease by saying whether tissue is hard or softOffers very high contrast between masses and host tissuesThe acoustic radiation force moves the tissue and detect distorsion by speckle trackingResults are quantitativeFound applications in breast,liver prostate,thyroid

Page 29: historical perspective of radiology

Ultrasound therapyRole in tissue ablation therapy in the form of high intensity focused

ultrasound

Exploits thermal effects of high power ultrasound beams focused on very small target tissue

Use frequency 0.7 to 3.3 mhz

More precise, easy to handle compared to radiotherapy

In ligament sprains,lithotripsy,cataract,acoustic targeted drug delivery,cancer therapy,thrombolysis etc

Page 30: historical perspective of radiology

Computerized Tomography

Also known as computerized axial tomography[CAT]

Imaging of a cross sectional slice of the body using X-rays.

Invented by Dr. G. N. Housfield in 1971. Received the Nobel prize in medicine in 1979.

The method is constructing images from large number of measurements of x-ray transmission through the patient.

The resulting images are tomographic maps of the X-ray linear attenuation coefficient.

Page 31: historical perspective of radiology

• Hounsfield built a prototype head scanner & tested it on a preserved human brain later on himself

• In 1971 CT scanning introduced into medical practice with a successful scan on cerebral cyst patient at Atkinson Morley’s hospital London

• In 1975 he built a whole body scanner

• In early experiments he used gamma source & it took 9 days to acquire image data & 2 ½ hrs to reconstruct image

• He replaced gamma source with x ray tube, scan time reduced to 9 hrs

Page 32: historical perspective of radiology

ALLAN M.CORMACK

• 1979 – nobel prize shared with DR.Hounsfield developed solutions to mathematical problems in CT

Page 33: historical perspective of radiology

• Principle - The density of the tissue passed by x ray beam can be measured from calculation of the attenuation coeffient

• Two processes of absorption photoelectric effect compton effect Measure transmission of thin beam of x rays through full

scan of body Image of that section taken from different angles,allows to

retrieve information on the depth Consists of square matrix of elements(pixel) & volume

element (voxel)

Page 34: historical perspective of radiology

CT-First generation

• Single x ray source • Beam – pencil beam

• Detector rotate slightly

• Translate/rotate scanner

• Duration of time 25 to 30 mins

• Resolution very poor

Page 35: historical perspective of radiology

Second generation

• Design – multiple detectors upto 30

• X rays beam – fan shaped

• Translate – rotate

• Duration of scan - <90 secs

Page 36: historical perspective of radiology

Third generation

• Design – larger array of detectors

• 300-700 detectors ,circular

• Beam – fan shaped x ray beam

• Tube and detector arrays rotate around patient

• Rotate rotate scanner

• Duration of scan – 5sec

Page 37: historical perspective of radiology

Fourth generation

• Detector – multiple >2000 arranged in outer ring fixed

• Beam – fan shaped

• Rotate – fixed scanner

• Duration of scan few seconds

Page 38: historical perspective of radiology
Page 39: historical perspective of radiology

Fifth generation

• X ray tube is a large ring that circles patient

• Use – cardiac tomography imaging “cine CT”

• Stationary/stationary geometry

Page 40: historical perspective of radiology

Spiral/helical ct

• Design – x ray tube rotates as patient moved smoothly into x ray scan field

• Source rotation,table translation,data acquition

• Advantages

speed-30 sec for abdomen,chest improved detections improved contrast improved reconstruction improved 3D images

Page 41: historical perspective of radiology

Seventh generation

• Design – multiple detector array• Turbo charged spiral• Upto 8 rows of detectors• Improvement in details• Cone beam and multiple parallel rows

of detectors• Reducing scan time,increase z

resolution• Very expensive

Page 42: historical perspective of radiology

Attenuation coefficients of several tissues expressed

in Hounsfield units.

Page 43: historical perspective of radiology

Magnetic Resonance Imaging (MRI)

Page 44: historical perspective of radiology

1946 - NMR Discovered by two physicists Felix Bloch &Edward Mills Purcell

1952 - They received nobel prize in physics

1971 - Use of NMR to produce 2D images made by Paul Lauterbur 1976 - First clinical human MRI

2003 - Nobel prize for Lauterbur & Mansfield

Uses strong magnetic fields and radiowaves to form image of the body

Used for medical diagnosis,staging of disease,follow up without exposure to radiation

Page 45: historical perspective of radiology

How it works

First – mri creates steady state of magnetism within human body by placing the body in a steady magnetic field

Second – mri stimulates body with radiowaves to change the steady state orientation of protons

Third – mri machine stops the radiowaves & register the body’s electromagnetic transmission

Fourth – transmitted signal used to construct internal images of body

Page 46: historical perspective of radiology

MRI machine

Page 47: historical perspective of radiology

Neuroimaging more sensitive for small tumors,CNS diseases guided stereotactic surgery radiosurgery(av malformations,tumors)

Cardiovascular MI,cardiomyopathies,CHD,ironoverload

Musculoskeletal spine imaging,joint disease,soft tissue tumors

Oncology,Liver,GI tract,functional MRI

Page 48: historical perspective of radiology

Specialized applications

Diffusion MRI MR angiography

MR spectroscopy Functional MRI

Real time MRI Interventional MRI

MR guided focused ultrasound Multinuclear imaging Molecular imaging by MRI

Page 49: historical perspective of radiology

• Advantage – ability to produce images in axial,coronal,saggital & multiple oblique planes

• Gives best soft tissue contrast of all imaging modalities

• CI – pacemakers,cochlear implants,aneurysm clips,metal fragments in eye

• Potential advancement – functional imaging,cardiovascular MRI,MRI guided therapy

Page 50: historical perspective of radiology

Nuclear Imaging

Page 51: historical perspective of radiology

PET

• Concept of emission and transmission tomography introduced by David E.Kuhl in late 1950s

• In 1961 James Robertson built the first single plane PET Scan,nick named “head-shrinker”

• Development of labeled 2FDG was a major factor in expanding in the scope of PET imaging

• The compound was first administered to two volunteers in aug 1976,at university of pennsylvania

Page 52: historical perspective of radiology

•Modern non invasive imaging technique for quantification of radioactivity in vivo

•Involves use of radiopharmaceutical injected into body & its accumulation in body detected,quantified & interpreted

Concept• radiolabelled biocompound 2-fluoro-2-deoxy-D-glucose injected iv• uptake of compound followed by breakdown occurs in cells• tumors have high metabolic rate hence this compound metabolised by • tumor cells• FDG metabolised to FDG 6 phosphate • further not metabolised by tumor cells hence accumulates• accumulation is quantified

Page 53: historical perspective of radiology
Page 54: historical perspective of radiology

Whole body PET

Page 55: historical perspective of radiology

Nuclear camera

Page 56: historical perspective of radiology

Radionuclide (isotope) scan

• Radionuclide is a chemical which emits a type of radioactivity called gamma rays

• Tiny amount of radionuclide put into body• Cells which are more active will take up more of

radionuclide & emits more gamma rays• Detected by gamma camera,converted into

electrical signal & sent to computer• Computers builds into different colours/shades of

grey

Page 57: historical perspective of radiology

SPECT (single photon emission computerized tomography)

Page 58: historical perspective of radiology

• Tomographic slice is reconstructed from photons emitted by the radio isotope in a nuclear medicine study

• SPECT is 3D Tomographic technique that uses Gamma Camera data from many projections and reconstructed in different planes

Page 59: historical perspective of radiology

SPECT Machine

Page 60: historical perspective of radiology

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