Iron chains to carry from his electric machines to evacuate the glass vessels.electric egg direct descendsnt of discharge tube Vitreous : rubbing glass on silk Resinous: rubbing resinous body, present in body with excess electrons
The Magdeburg hemispheres are a pair of large copper hemispheres, with mating rims. They were used to demonstrate the power of atmospheric pressure. When the rims were sealed with grease and the air was pumped out, the sphere contained a vacuum and could not be pulled apart by teams of horses
Investigating discharge of high tensn in perfect vacuum….achieved high vacuum with no discharge..glass cracked to
Improved vacuum pumps..fluorescence size increased as the tube was evacuated..found that they travel in straight path produce fluorescence and cast shadow of the object in their way.
Not permitted to acces dr.hertz supply of platinocyanide
Turned on alow pressure crookes tube wrapped on black paper and applied power with
Placed hand between crookes tube and fluorescent screen..cast shadow
To this breathtaking revolution
this was hou US responded to discovery of wilhem roentgen the electrical engineer New York..jan 7 1896
Skiagram: a photographic image on a phosensitive surface that can be traced formed by rays other than visible rays
Photographic glass plate wrapped in rubber dam put in mouth between teeth and tongue
Fried rich otto walkhoff succeeded in making skull radiograph 2 yrs later. 30 mins exposure
Koenig: used focus tube, cathode rays reflected by sheet of platinum at 45 deg
Also used crookes tube and ruhmkorff induction coil Mentioned importance of keeping film and object at right angle to xrays , film as close to object as possible and at the same time parallel to the object
Clinical xray setting holder with modelling compound his patient his asistant
Source of high potential current. Pri:few turns of coarse wire around soft iron.sec: many turns of insulated fine wire. Interrupter interrupts the pri currents to generate magnetic impulse. Mercury type: platinum tipped rod in and out of mercury with help of electric motion .electrolytic: universal.: like cell or battery tesla high frequency
Gas tubes: fix or stationary, vacuum could not be altered, incomplete vacuum low; dark blue..high vcuum: yellow apple green, 3-4 inches spark: soft, 7-10 were hard 4-7 dental caterpillar like Regulator : self regulatingdegree of vacuum can be changed Lilienfield effect: patent us..cathode did not emit electrons
Cathode tube: tungsten as filament cathode graeter flexibility in quality and quantity of xray, tube stability, smller tube size longer life anode : tungsten backed by copper
Voltage supply wires: uninsulated open and unguarded so tube and high volt component were guarded in oil filled compaertment: insulator. Electrical and fire hazard eliminated
Early pioneers suspended x-ray tube from ceiling, tube stand almost fixed or lim mobility
Curved fil inside the mouth lingual to teeth and used slit xray beam to rotate around the patient. Principle: if film moves at a speed that follows the moving projection at certain point this will be always projected at same spot. Stationary rotation: rotation center shifted by moving the pt., single center of rotation 2 center and three center.
Internal structure of object can be reconstructed from multiple projections of object. naI, CaF Bigerminate. Scintillation or gas ionization detectors
Pt placed inside a large magnetic field.radiowaves placed into pt by coil transmitter at 90 deg to magnetic field.it develops net magnetic vector parallel to applied magnetic field.after application of RF signal energy is released from body detected by recieiver coil and image constructed.
Complete image from single data sample. Single shot: entire range of phase encoding in one TR ( repetition time).. Multishots divided to multiple tr periods. Decresed imaging time, decresed motion artifact
Sound travels through medium encounters impedance “acoustic impedance” some reflected some transmitted and some transferred. Reflected sound is picked by transducer and and converted to electric impulses ansd displayed.
Compounds have affinity for target tissues.radiation emissions are detected and imaged
Localised in the areas of increased osteoblastic activity. Sr showed clearly that bone scan consistently detected lesions months before radiograph of the skeleton become abnormal
History of radiology
HISTORY OF RADIOLOGY
Dr. Jyotsna Rimal
Additional Professor, HOD
Dr. Iccha Kumar Maharjan
Department of Oral Medicine and Radiology
Nothing materializes as if by magic overnight.
Even ROENTGEN’s discovery depended upon
development and application of three converging
ELECTRICITY, VACCUM and MAGNETISM
• Prologue to discovery
• Discovery of X- Rays
• Post discovery
• Insight to oral radiology
• The other side of coin: radiation hazards
• Fundamentals in radiology
• Growth of dental radiology
• Panoramic Radiography
• Computed Tomography
• Magnetic resonance imaging
• Nuclear imaging and medicine
• Bone scan
• Oral radiology journals.
• Radiology in Nepal
• Who, when, what, how, which
PROLOGUE TO DISCOVERY
• 600 BC
• Phoenician voyager Thales of Miletus
• “Delicate substance fair in color and beautiful in
• Baltic shores
• Electron or Amber
• Gilbert gave the term “Electricity”
• Stephen Gray discovered that current would flow over the
conductor for great distances.
• Abbe Nollet “electric egg” became
direct descendent of discharge tube.
• Charles DuFay (1730) – vitreous and
• Otto Von Guericke (1648) – first air pump used in formation of
Experiment on ‘Magdeburgh Hemispheres’
• Evangelista Toricelli (1643) – Mercury Barometer; permanent
• Francis Hauksbee – electricity producing friction machine within
DISCOVERY OF X- RAYS
• Sir William Morgan
• Obtained a vacuum so that there was no discharge.
• Glass cracked – display of colors
Red, Violet, BlueUnknowingly he was first to
produce X- Rays
• Michael Faraday
• First experiment on electric discharges
• Fluorescence as “Radiant Matter” : 4th state
• Wilhelm Hittorf
• Identified CATHODE rays
• Philip Lenard
• Cathode rays pass through aluminium window
• Cause fluorescent screen to glow 5 cms in air “Lenard’s Ray”
• Had he used barium platinocyanide instead of pentadecyl paratolylketon
(discoverer of X- Rays)
• Proposed Inverse Square Law
• Humanity owes honor and gratitude for discovering the most
striking and outstanding properties of cathode rays to
Professor Wilhelm Conrad Roentgen
• November 8, 1895 Friday evening
• Research on electric discharge in diluted gas
• Crooke’s tube and Ruhmkorff induction coil
• Fluorescent screen with barium platinocyanide began to glow
• Rays produced when cathode rays encountered matter
• The rays could not be reflected or refracted
• They were unaffected by magnetic and electric fields
• Termed X- Rays (X = unknown)
• Roentgen Rays
• Property of fluorescence and penetration
• Shadows cast on screen
FIRST MEDICAL RADIOGRAPH OF
HUMAN BODY• 15 minutes, Bertha
• Dec 22, 1895
• First industrial radiograph: Roentgen’s Shotgun
• A New Kind of Rays: A preliminary communication
• A New Kind of Rays: continued
• Further observations on A New Kind of Rays
• # Fact that X- Rays could be polarized and defracted
• 1901- First Nobel Prize in PHYSICS
• Honorary M.D Degree- Maximilan University, Wurzberg
• The Ruhmford Gold Medal of the Royal Society (British)
• The Iron Cross from Hindenberg
• The year 1896- momentous
• Major discoveries and inventions in the field of radiodiagnostics and the
emergence of radiotherapy
• Total of 49 books and brochures, and 1,044 scientific essays were
written on the scientific aspects and possible applications of the newly
• A multitude of these publications dealt specifically with possible
applications in medicine.
• Four years after his wife, Röntgen died at Munich on February 10,
1923, from carcinoma of the intestine.
INSIGHT TO ORAL RADIOLOGY
• Who took the first dental radiograph ??? UNCERTAIN
• Honors shared between Dr. Friedrich Otto Walkhoff, Wilhelm
Koenig Wilhem, Frank Harrison and C. Edmund Kells
• Crude but recognizable dental skiagrams
• 1896- Late winter and early spring
• Dr. Friedrich Otto Walkhoff
• Completed first dental radiograph
• 25 mins exposure
• Crown of maxillary and mandibular teeth, the first “Bitewing”
• 1896: first dental roentgenologic laboratory- Fritz Giesel
• Professor Wilhem Koenig Wilhem- Feb 2, 1896
• Giesen- 14 dental radiographs of his own mouth
9 minute exposure per film
• Frank Harrison- Demonstration of “Pulp chamber”
10 minute exposure
• William J Morton, 1896
• First recorded dental radiograph in US
• Revealed presence of impacted tooth which was otherwise invisible.
FATHER OF DENTAL RADIOLOGY
• Dr. C Edmund Kells,
First to use compressed air in dental office
First to hire “lady assistance” or “ lady in attendance”
First radiograph of root of teeth was made in 1896.
First advocate of right angle or paralleling technique.
First dentist to use radiograph in root canal therapy: may 10, 1899
• Dental Cosmos, 1899 : importance of keeping film and object at right
angles to the source of X- Rays.
• Journal of Dental Service, “Lady in Attendance”: She would eventually
be found in every dental office.
THE OTHER SIDE OF COIN: RADIATION HAZARDS
• 1896, Frank Harrison: probably first to report occurrence of radiation
• 1896, March 23 : Dr. John Daniel mentioned about hair loss from head
of colleague that was photographed with radiography.
• 1896, July 22: W. Marcuse published first microscopic study of effect of
radiation on tissues.
• Elihu Thomson: first X- Ray worker, Roentgen rays cause adverse effects.
1900, Kienbock: irradiation of rats
1901, William Rollins: irradiation of guinea pigs
Direct relationship between X-Ray beams and biologic effects was
• At age 40, Kells first began his work with x-rays
• Unaware of the unseen danger of cumulative doses of radiation.
• Often held the films in place with his own fingers.
• By age 50, he had developed cancer in his right hand.
• Over the next 20 years, Kells endured 42 operations
eventually losing his hand, arm, and shoulder.
• On May 7, 1928, at age 72, he committed suicide - due
to great suffering
FUNDAMENTALS IN RADIOLOGY
• X- Ray Machine
• X-Ray tube
• Adjustable tube stand
• The Darkroom
Regulator Tubes, 1896,
Queen and Company
Vaccum Tubes, 1911, J.E.
GOLDEN AGE OF RADIOLOGY
• Clyde Snook, 1907
• 110 kvp, 200mA
• William David Coolidge,
SHOCKPROOF DENTAL X-RAY UNIT
• 1918- 1919, Coolidge and General Electric Company
• Victor CDX- shockproof dental X-Ray unit.
Adjustable tube stand
• Dr. William Rollins, 1896
• Protective screen and adjustable Diaphragm
• First to publish Harmful effects of X- Rays.
• First dental radiograph- glass plate
• Kells and Rollins- Photographic film wrapped in black paper and rubber
dam ( lack of emulsion sensitivity)
• First machine wrapped dental X- Ray film, 1919: Regular film KODAK
• 1920: cellulose nitrate base (inflammable)
• 1924: non inflammable cellulose triacetate (expensive, wrinkled and
tendency to break)
• Double emulsion film: Radiatized film (Kodak)
• 1940: the ultra speed (improved radia tized)
• 1955: D speed Film
• 1960: polyester base
• 1980: Ekta speed Film (Kodak)
• 2000: F speed film
• Closet with or without running water (3.5 ft* 5ft)
• Developing time and solutions varied with operator
Covering sensitive material with developing agent
Adding a preservative
Adding an accelerator
Adding a bromide
• 1896, Kells- 30-60 mins
• 1909: tank development, 5 min development at 65 F
• 1918: Eastman Kodak company, darkroom with tank processing
• 1920: film hangers
• 1910: Automatic processor
• 1981: Day light processor
GROWTH OF DENTAL RADIOLOGY
“Dentistry’s forgotten man” “Father of Radiation Protection”
William Herbert Rollins (1852-1929)
• Intraoral cassette and oral fluoroscope.
• First dental X-Ray appatratus but never commercialized.
• First to suggest the use of radium for cancer.
• First to advise three precautions to X-Ray users (1901, guinea pigs)
Wear lead glasses
Enclose X-Ray tube in lead housing
Irradiate only area of interest, rest cover with radio- opaque material.
• Introduced collimator to reduce beam size and recommended long
target film distance for image quality and patient safety.
• Advocated draping of patient with non- radiable material.
• Pioneered sandwiching the film between two intensifying screens to
• Suggested safe and harmless radiation dose to be determined.
• February 24, 1901, he published a resounding article entitled "X light
"Undoubtedly the greatest genius the dental profession has ever
known...He gave more to the dental, medical radiologic scientific world
than any other practitioner of our profession. Yet no dentist has received
so little recognition for his contributions."
• Rollins, 1903: First to suggest selective filtration of X-Ray beam
• Kells, 1903: First X-Ray Laboratory, THE NEW ORLANDS X-RAY LAB
• Dr. Weston A Price, 1904:
First proposed X-Ray production based on “Rule of Isometry”
Developed flexible leaded rubber, first pair of leaded gloves for
Established relationship between nutrition and dental health.
• Howard Riley Raper, 1909: A part time instructor at
Indiana Dental College, Indianapolis
Teaching of Dental Radiology in every school in United
1901- 1910, first course of radiology initiated, professor of
1911- 1913, series of papers in Dental items of interest
1916, Elementary and Dental Radiography, new disciple RADIODONTIA
1918, Angle meter and different vertical angles for different projections
1925, approached Eastman Kodak Company for Bite- wing Film
• Franklin W McCormack: Paralleling technique to practical use
Hand wrapped dental films in black paper, added flat metal plate,
wrapped both in wax paper
Metal plate prevented back scatter radiation
Mc Cormack long distance technique, lecture at Missouri Stale Dental
Association- 55th annual meeting at Kansas, April 12 1920
Journal of Dental research, 1920, first layman to publish research in
• Dr. Gordon Fitzgerald, 1940
Designed long cone for dental X- Ray machine
1947-1950, Journal of American Dental Association, four
articles, “Long Cone Paralleling Technique”
• 1949, American Academy of Oral Roentgenology, American
Academy of Dental Radiology.
• Dr. H Numata proposed (1933) and experimented (1934) with rotational
• Y.V Paatero, Institute of Dentistry Finland proposed (1946) and experimented
(1948) slit beam Panoramic radiography
• 1960, S.S White and Company marketed PANOREX
• 1968, International Association of Dental Maxillofacial Radiology was
• 1969, Godfrey Hounsfield: Prototype scanner with
Americium light source
• 1970: Computed tomography, announced in 1972,
mathematics (1917), astrophysics (1956)
• 1971: First scanner installed,
• 1972: commercially viable CT scanner (Thorn EMI central
research laboratories), installed in Atkinson Morley’s Hospital in
• 1974: First CT system from medical equipment manufacturer SIRETOM
• 1975: introduction of CT unit of 5000 series, 18 sec scanning time.
• 1976: Whole body CT imaging started, Fan beam and rotating anode
• 1979: Godfrey Newbold Hounsfield, Dr. J Ambrose and Allan McLeod
Cormack shared Nobel Prize in Medicine.
• 1980, Andrew Castagini: Electron beam CT
• 1987, Dr. Michael Rhodes: First Dental CT reformatting package
• 1990, Wili Kalender and Kazuhiro Katada: The first spiral CT was Siemens
SOMATOM Plus system
• 1992: Integrated CT angiography
• 1993: Interactive CT
• 1998: MDCT
MAGNETIC RESONANCE IMAGING
• 1946, Felix Bloch and Edward Purcell: Nobel Prize 1952, discovery of
• 1971, Raymond Damadian: Nuclear Magnetic Relaxation time of tissue
and tumors differs
• 1973, Paul Lauterber: Demonstrated MRI on small
test tube samples
• 1975, Richard Ernst: Proposed MRI using Phase and
• Jul 3, 1977: First MRI performed on human, Dr.
Raymond Damadian, Dr. Larry Minkoff, Dr. Michael
• 1977, Peter Mansfield: Echo- Planar imaging
• 1987: Echo- Planar performed real time movie imaging of single cardiac
• 1987, Charles Dumoulin: perfecting Magnetic Resonance Angiography
• 1991, Richard Ernst: Nobel Prize in Chemistry
• 1992: Functional MRI (fMRI) developed
• 2003, Paul C. Lauterbur, Sir Peter Mansfield: Nobel Prize in Medicine.
NUCLEAR IMAGING AND MEDICINE
• Invention of the cyclotron: Ernest Orlando Lawrence (1901-1958)
• 1930: first cyclotron which was only 4 inches in diameter.
• It involved 2 D-shaped magnets, which created a circular magnetic
field, with a small gap between them.
• 1935: John Lawrence, Injected radioactive phosphorus in mice
• 1939: Ernst Lawrence, Nobel prize in PHYSICS
• 1939: first successful radio isotopic treatment of polycythemia
vera using phosphorus-32
• 1946: Major achievement, iodine- 131 halted growth of thyroid cancer
• 1983, John Lawrence: Fermi Award “pioneering work and continuing
leadership in nuclear medicine.“
• 1980s: digitization of Nuclear Medicine
• RADIONUCLIDES: I-131, Ga- 67, Se- 74, Tc-
• Scintillation Camera: ANGER cameras
Convert them to light and then to voltage
Reconstruction to planar image-
• 1961, Fleming et al: First radionucleide skeletal imaging using Sr- 85
• F-18 and Ca- 45 (previously used)
• Development of Mo-99, Tc phosphate- 99m and Y-scintillation camera
lead to phase out of previously used substances.
• Chester Carlson, 1937: imaging method discovered
• 1949: First known use
• 1963, Pogorzelska- stronczak B: attempted xeroradiography in
• Began in 2008 with few people from John Hopkins, grown to include
>3500 contributors from 200 countries.
• Moves ahead to answer the need for radiology and imaging technology in
resource limited regions and communities of world.
• Asian members: NEPAL, Bhutan, India, China, Jordan, Laos
• Radiology is a medical specialty that uses imaging to diagnose and treat
diseases seen within the body. A variety of imaging techniques such as X-
ray radiography, ultrasound, computed tomography (CT), nuclear
medicine including positron emission tomography (PET), and magnetic
resonance imaging (MRI) are used to diagnose and/or treat diseases
• Pioneers of radiation, radiology and radio diagnosis have put upon their
whole life into it just to come up with a spark of light that can form image
or shadow that is castable and hence interpretable.
• Diagnosis of hard and soft tissue lesions of body including head and
neck has become so easy and trustworthy that most of the
radiodiagnosis tool have become routine investigations.
• History of radiology is not just about cramming of names of inventors,
the dates and the inventions but an ODE to those great people who
brought about magical change in medical fraternity, its about
RESPECTING them and getting MOTIVATED from them
• Which was the vaccum tube used by Sir Wilhem Conrad Roentgen?
a) Lenard’s tube
b) Ruhmkorff’s tube
c) Crooke’s tube
d) Morgan’s tube
• When was International Association of Dental and Maxillofacial
• Who revealed presence of impacted tooth for the first time in
a) Frank Harrison
b) William J Morton
c) Wilhem Koenig Wilhem
d) C. Edmund Kells b
• Nepalese Journal of Radiology was launched in:
d) 2013 c
• Who is known as Father of Radiation Protection?
a) William Herbert Rollins
b) Howard Riley Raper
d) Gordon Fitzgerald a
• Karjodkar FR. Textbook of Dental and Maxillofacial Radiology. 2nd
edition. New Delhi: Jaypee Brothers Medical Publishers (P) Limited;
• DiSantis DJ. Early American Radiology: The Pioneer Years. AJR.
1986, October; 147:850-853
• Thomas A, Busch U. The Story of Radiology. Vienna: European
Society of Radiology; 2012 (1)
• Thomas A, Busch U. The Story of Radiology. Vienna: European Society of
Radiology; 2013 (2)
• Tsung J. History of Ultrasound and technological advances. New York:
Mount Sinai School Of Medicine
• Carlson S. A Glance At The History Of Nuclear Medicine. Acta Oncologica.
• Brant WE, Budhathoki TB, Pradhan R. Radiology in Nepal.
• Udoye CI, Zafarzadeh H. Xeroradiography: Stagnated after a Promising
Beginning? A Historical Review. Eur J Dent. 2010 Jan; 4(1): 95–99
• Stronczak P. ATTEMPTED APPLICATION OF XERORADIOGRAPHY IN
STOMATOLOGY. Przeal Radiol Med Nukl. 1963 May-Jun;27:265-75
• Curry TS, Dowdey JE, Murry Cr. Christensen’s Physics of Diagnostic
Radiology. 4th eition. Philadelphia: Lippincott Williams and Wilkins; 1990
• The name of scientist associated with Skiagram is Rowland.
• The two properties of X- Rays:
a) Polarized: Vibration of light in a single plane. It can be brought about by transmission,
reflection, refraction or scattering.
b) Diffraction: it refers to slight bending of light as it passes around the edge of an object.
• MRI test tube: 4.2 mm diameter test tube contained capillary tube of 1mm diameter with
• Slit beam: a beam of X-Ray coming out from vertical slit aperture, a type of collimator.
• Different types of collimator: diaphragm (7cm diameter), tubular, rectangular and
slit ( used only in OPG) collimator.
• What changes the speed of the film?
• First commercially available intra-oral X-Ray films came in 1913 whereas the same
for extra- oral came in 1918.
• Advantages of helical CT:
• Which gas is present in ionization gas detectors?
Hydrogen and oxygen, Nitrogen-phosphorus, Argon, xenon
• Scientist associated with functional MRI(fMRI):
1890, Charles Sherrington linked brain function to blood flow.
1991, John Bellirean carried first fMRI.
• Multiplanar Imaging:
Allows image to be created from original axial plane in either coronal saggital or
It allows isotropic imaging in which image quality of reconstructed multiplanar iamge
is same as original axial image.
• New MRI in Kathmandu:
Grande International Hospital: 1.5 T digital broad band MRI, first of its kind in Nepal
with outsanding image quality and scan.
• Nuclear imaging in Kathmandu:
Gamma imaging and research center.
Metro radiology and imaging center.
National Academy and Medical Sciences (NAMS)
• Early radiation hazards that dentist can detect:
Mucositis, Xerostomia, Superficial or Oppurtunistisc fungal infection, Soft tissue Necrosis.
• 1896, Thomas Edison, Calcium Tungstate screen was a kind of first intensifying screen used
in general radiology.
• Doppler Ultrasonography (Usg): Christian Andrews Doppler in 1842 formulated Doppler
Change in frequency of transmitted waves when relative motion exists between source of
wave and observer.
Doppler Usg: 1950
• 4D Usg: 3D picture in real time i.e, the 3D object moves.
HISTORY OF CBCT
• In 1988, cone beam computerized tomography (CBCT) was introduced to dentistry.
• This technology offered 3-dimensional visualization and more complex and more accurate
imaging compared to analog and digital radiographs.
• Because CBCT exposure incorporates the entire FOV, only one rotational sequence of the
gantry is necessary to acquire enough data for image reconstruction.
• Medical CT, which uses a fan-shaped x-ray beam in a helical progression to acquire individual
image slices of the FOV and then stacks the slices to obtain a 3D representation. Each slice
requires a separate scan and separate 2D reconstruction
• With larger FOVs, is a limitation in image quality related to noise and contrast resolution
because of the detection of large amounts of scattered radiation
• Advantages in dentistry:
Rapid scan time
Interactive display modes applicable to maxillofacial imaging