xray bascis ppt

1. XRAY-BASICS
GROUP DISSCUSSION
MODERATOR
DR.MANOJ KUMAR
PRESENTED BY
DR.NABA KUMAR BARMAN
JR 1
MD
FICS (INTERVENTIONAL RADIOLOGY)

2. RADIATION:ENERGY THAT COMES FROM SOURCE AND TRAVEL THROUGH SOME MATERIAL
OR THROUGH A SPACE
RADIATION TWO TYPES
A.IONISING RADIATION
B.NON IONISING RADIATION

3. IONISING RADIATION NON –IONISING RADIATION
ELECTROMAGNETIC RADIATION:
CONSIST ENERGY IN SMALL PACKETS
CALLED PHOTON
UV RAYS
GAMMA RAY VISIBLE RAYS
COSMIC RAYS INFRA RED RAYS
XRAY MICRO WAVES
PARTICULATE RADIATION RADIO WAVES
ALPHA RAYS,
BETA RAY
PROTON
NEUTRON

7. XRAY IS NOTHING BUT HIGH ENERGY PHOTON TRAVELLING IN WAVE FORM
• PHOTON BEING A PARTICLE IT FOLLOW WAVE AND PARTICLE THEORY
• IT TRAVEL WITH THE SPEED OF LIGHT
• IT IS FORM OF ELECTROMAGNETIC RADIATION JUST LIKE ULTRAVIOLET ,
RADIOWAVE, GAMMA AND INFRA RED RAY
HIGHLY PENETRATING
AVERAGE ENERGY OF XRAY PHOTON IN DIAGONOSTIC XRAY BEAM IS THE ORDER OF
30 Kev
PROPERTIES OF XRAY

8. STEPS OF XRAY
1.X –RAY TUBE :PRODUCTION OF XRAY:BREMSSTRAHLUNG /CHARACTERISTIC
2.INTERACTION WITH MATTER (BODY) :PHOTOELECTRIC /COMPTON EFFECT
3.INTENSIFYING SCREEN(LUMINESCENCE
FLUORESCENCE
U
U
USE RARE EARTH MATERIALS LIKE GADOLINIUM
LANTHANUM OR CALCIUM TUNGSTATE
XRAY FLIM
5. PROCESSING OF XRAY FLIM(DARK ROOM)

11. FILAMENT :MADE OF THIN TUNGSTEN WIRE 2 MM DIAMETER
LENGTH -<1 CM
TUNGSTEN USE BECAUSE
1 HIGH ATOMIC NUMBER(Z-74)
GOOD THERMIONOC EMITTER (GOOD EMITTER OF ELECTRON)
CAN BE MANUFACTURED INTO THIN WIRE
VERY HIGH MELTING TEMPARATURE (3422 degree)
SIZE OF FILAMENT SRELATED TO SIZE OF FOCAL SPOT
IS RUN THROTHERMAL STABILITY IS FURTHER ENHANCED BY
ADDITION OF THORIUM
CATHODE

12. THIS ELECTRON GOES AND HIT THE ANODE AND XRAY IS
PRODUCED (LINEAR ACCELERATION)
.SINCE HEAT IS GETTING PRODUCED AT CATHODE ,IT IS
MADE UP OF SUBSTANCE WHICH HAS HIGH MELTING POINT
THAT IS
When a metal is
heated its atoms absorb thermal energy,
and some of the electrons in the metal acquire
enough energy to allow them to move
a small distance from the surface of the
metal (normally, electrons can move within
a metal, but cannot escape from it). Their
escape is referred to as the process of
thermionic emission, which may be defined
as the emission of electrons resulting
from the absorption of thermal energy.
The electron cloud surrounding the filament,
produced by thermionic emission,
has been termed the "Edison effect."

13. Electrons are released by thermionic
emission, the electron current is determined by
the temperature which depends on the wire
current. The electron current is approximately 5
to 10 times less than the wire current.
a focusing cup with a negative bias voltage applied to focus the
electron distribution.

14. ANODE
ELECTRON IS HITTING THE ANODE SO THAT
HEAT IS PRODUCE SO ANODE IS ALSO MADE UP
TUNGSTEN
RHENIUM IS ADDED TO ANODE TO INCREASE ITS
TENSILE STRENGTH
 THE ANODE IS ATTACHED TO A COPPER ROD
WHICH IS BEING A GOOD CONDUCTOR OF HEAT
HELPS IN HEAT DISSIPATION
The anode is the target electrode and is maintained
at a positive potential difference Va with respect to the
cathode. Electrons are therefore accelerated towards
the anode: E = wVa
Upon impact, energy loss of electrons takes place by scattering and
excitation processes, producing heat, electromagnetic radiation and X-
rays.
 0.5% of the electron energy is converted into X-rays.

15. The two major anode configurations are:

16. The stationary anode is the classical configuration, tungsten
target for X-ray production and copper block as heat sink

17. The rotating anode is a tungsten disc, large rotating surface
area warrants heat distribution, radiative heat loss (thermally
decoupled from motor to avoid overheating of the shaft)

18. The anode angle is defined as the angle of the target surface
to the central axis of the X-ray tube.
The focal spot size is the anode area that is hit by the
electrons.
effective focal length = focal length • sinq
The angle q also determines the X-ray field size coverage. For
small angles the X-ray field extension is limited due to absorption and
attenuation effects of X-ray photons parallel to the anode surface.
The anode angle q determines the effective focal spot size:

19. A small angle in close distance is recommended for small spot
coverage, a large angle is necessary for large area coverage.

20. INTERACTION OF ELECTRON WITH ANODE A) BREMSSTRAHLUNG RADIATION
B)CHARECTERISTIC RADIATION

21. BREMSSTRAHLUNG REACTION
BREMSSTRAHLUNG REACTION IS PRODUCED BY PROJECTILE ELECTRON INTERACTION
WITH THE NUCLEUS OF TARGETED ATOM
HIGH ENERGY ELECTRON BOMBERDING A TARGET ,SPECIALLY TARGET THAT HAVE HIGH PROTON NUMBER
(Z).WHEN BOMBERDING ELECTRON PENETRATE INTO THE TARGET ,SOME ELECTRON TRAVEL CLOSE TO
NUCLEUS DUE TO ATTRACTION OF ITS POSITIVE CHARGE AND ARE SUBSEQUENTLY INFLUENCED BY
ITS ELECTRIC FIELD .THE COURSE OF THIS ELECTRON WOULD BE DEFLECTED AND
A PORTION OR ALL OF THEIR KINETICS ENERGY WOULD BE LOST .THE
LOST ENERGY IS EMITTED AS X-RAY PHOTON ,SPECIALLY BREMSSTRAHLUNG REACTION
90 PERCENT XRAY ARE DUE TO THIS REACTION

23. CHARECTERISTICS RADIATION
 WHEN FAST MOVING ELECTRON COLLIDES WITH K SHELL ELECTRON THE
ELECTRON IN THE K SHELL IS EJECTED (PROVIDED THE ENERGY OF INCIDENT
ELECTRON IS GRATER THAN THE BINDING ENERGY OF K SHELL ELECTRON)
LEAVING BEHIND A HOLE .THIS HOLE IS FILLED BY AN OUTER SHELL ELECTRON
(FROM L –SHELL,M-SHELL ) WITH AN EMISSION OF SINGLE XRAY PHOTON
,CALLED CHARECTERISTIC RADIATION WITH AN ENERGY LEVEL EQUIVALENT TO
ENERGY LEVEL DIFFERENCE BETWEEN THE OUTER AND INNER SHELL ELECTRON
INVOLVED IN THE TRANSITION
AS OPPOSED TO NORMAL X-RAY IN MAMOGRAPHY MOST OF THE RADIATION IS
CHARECTERISTICS

25. INTERACTION OF XRAY WITH HUMAN BODY
A)PHOTOELECTRIC EFFECT
B)COMPTON EFFECT
PHOTOELECTRIC EFFECT:INTERACTION OF INCOMING PHOTON WITH INNERSHELL ELECTRON
IT IS SIMILAR TO CHARECTERISTIC RADIATION ONLY DIFFERENCE IS IT IS INTERACTION
WITH HUMAN BODY

26. COMPTON EFFECT
INTERACTION OF PHOTON WITH OUTERSHELL
ELECTRON
CROMPTON EFFECT REDUCES CONTRAST IN
XRAY IMAGE

27. PHOTOELECTRIC COMPTON
INNER SHELL ELECTRON OUTER SHELL ELECTRON
INCIDENT ENERGY COMPLETELY
ABSORB
INCIDENT ENERGY PARTIALLY ABSORB
XRAY 70 Kvp XRAY 140 Kvp
INCIDENCE INCREASES WITH ATOMIC
NO
NO EFFECT
RADIOGRAPHY CT SCAN

39. The X-ray beam size is limited by a collimator system, the
collimators are lead for complete absorption.

40. Collimator design allows to optimize
the point exposure!

54. INTENSIFING SCREEN

64. THE SCATTERED PHOTON ALSO REACHES THE FLIM SCATTER
SIMPLY PRODUCES UNIFORM BACK GROUND
IT DOE NOT CONTRIBUTE TO IMAGE,BECAUSE SCATTER
REDUCES IMAGE CONTRAST ,THIS SCATTER REMOVED
BY ANTISCATTER GRID,THIS GRID CONSIST OF SERIES OF
NARROW LEAD STRIPS WITH RADIOLUCENT INTERSPACE
MATERIAL TO REMOVE SOME OF SCATTER
RADIATION DOSE OF THE PATIENT IS SLIGHTLY INCREASE AS
THE USEFUL RADIATION BLOCK BY THE GRID

68. PROCESSING OF XRAY FLIM

103. TYPES OF RADIOGRAPHY
 CONVENTIONAL RADIOGRAPHY
 DIGITAL RADIOGRAPHY 1)COMPUTED RADIOGRAPHY
2)DIRECT RADIOGRAPHY
DIRECT RADIOGRAPHY :IT IS ONE OF THE MOST MODERN IMAGING METHOD ON
WHICH SELECTIVE WINDOW SETTINGS OF SOME IMAGE VISUALISATION OF LUNG
FIELD ,MEDIASTINUM ,BONE OPTION AVILABLE

107. COMPUTED
RADIOGRAPHY
DIRECT RADIOGRAPHY
STEPS REQUIRED LOAD CASSSETTE
POSITION PATIENT
POSITION TUBE
PERFORM EXPOSURE
TRANSPORT CASSETTE
PROCESS CASETTE
ASSESS IMAGE QUALITY
AND EXAMINATION
POSITION PATIENT
POSITION TUBE
PERFORM EXPOSURE
IMAGE IS SENT TO
VIEWING STATION
ASSESS IMAGE QUALITY
END EXAMINATION
ADVANTEGES MANIPULATION AND
POSITIONING OF IMAGE
FOR CROSS TABLE
PROJECTION IS POSSIBLE
(TRAUMA PATIENT)
RELATIVELY FASTER
WORK FLOW DUE TO
ELEMINATION OF
CASSETTES
SHORTER TURN AROUND
TIME FOR VIEWING
IMAGE
DISADVANTAGES SLOWER MORE COMPLEX
WORKFLOW
HIGHER COST