1. Basic Of X-Ray ProductionBy : M. Khalis , JKN Johor
2. Atoms All atoms share the same basicstructure. During past
200 years, scientist haveproposed different models.
3. Daltons Model
4. Thomsons Model End of 1800s Thompson discovered that
atomswere not simple, solid spheres. Atoms contained subatomic
particles.- very small, negatively charged- ELECTRONS
5. Thomsons Model Also knew that atoms were
electricallyneutral- Most contain enough positive charge to balance
negative charge of electrons. Developed model where electronswere
stuck into a positively chargesphere.- Like chipsmore
6. Thomsons Model
7. Rutherfords Model By early 1900s, scientist knew
thatpositive charge of atom comes fromsubatomic particles called
protons. 1911 Rutherford begins to testtheory His experiment led
him to believe thatprotons are concentrated in a smallarea at
center of atom. - called this area the nucleus
8. Rutherfords Model Rutherfords model describes an atomas
mostly empty space, with a centernucleus that contains nearly all
themass.- seperti biji dalam buah rambutan.
9. TRIVIAA hydrogen atom lost its electron andwent to the
police station to file amissing electron report. He wasquestioned
by the police: "Havent youjust misplaced it somewhere? Are yousure
that your electron is really lost?"Im positive." replied the
atom.
10. Bohrs Model Modified Rutherfords model in 1913 Proposed
that each electron has acertain amount of energy. - Helped electron
move aroundnucleus. Electrons move around nucleus inregion called
energy levels. Energy levels surround nucleus inrings, like layers
of onion
11. Bohrs Model Has been called planetary model- Energy levels
occupied by electrons are like orbits of planets at different
distances from the sun (nucleus)
12. Electron Cloud Model Model accepted today Electrons dart
around in an energylevel Rapid, random motion creates acloud of
negative charge aroundnucleus Electron cloud gives atom its size
andshape
15. Productions Of X-RayRequirements: a source of fast moving
electrons must be a sudden stop of the electrons motion in stopping
the electron motion, kinetic energy (KE) is converted to EMS
energies Infrared (heat), light & x-ray energies
16. Productions Of X-Ray Power is sent to x-ray tube via cables
mA (milliamperage) is sent to filamenton cathode side. Filament
heats up electrons boil off Negative charge
17. Productions Of X-Ray Positive voltage (kVp) is applied
toANODE Negative electrons = attracted acrossthe tube to the
positive ANODE. Electrons slam into anode suddenly stopped. X-RAY
PHOTONS ARE CREATED
18. Productions Of X-Ray Electronbeam is focused from the
cathode to the anode target by the focusing cup Electronsinteract
with the electrons on the tungsten atoms of target material PHOTONS
sent through the window PORT towards the patient
19. QUIZ C B
20. Principles Part Of X-RayImaging System Operating Console
High-voltage generator X-ray tube The system is designed to provide
alarge number of e- with high kineticenergy focused to a small
target
21. QUIZ 2 Projectilee- interacts with the orbital e- of the
target atom. This interaction results in the conversion of e- ___
energy into ________ energy and ________ energy.
22. Tube Interaction3 possible tube interactions Tube
interactions are generated from _____ slamming into ________? Heat
(99%), EM energy as infraredradiation (heat) & x-rays (1%)
X-rays = Characteristic (20%) or Bremsstrahlung (80%)
23. Heat Mostkinetic energy of projectile e- is converted into
heat 99% Projectilee- interact with the outer- shell e- of the
target atoms but do not transfer enough energy to the outer- shell
e- to ionize
24. Heat is an excitationrather than an ionization
25. Heat Production Production of heat in the anodeincreases
directly with increasing x-ray tube current & kVp Doubling the
x-ray tube currentdoubles the heat produced Increasing kVp will
also increase heatproduction
26. Bremsstrahlung Radiation Heat& Characteristic produces
EM energy by e- interacting with tungsten atoms e- of the target
material Bremsstrahlungis produced by e- interacting with the
nucleus of a target tungsten atom
27. Bremsstrahlung RadiationA projectile e- that completely
avoids the orbital e- as it passes through a target atom may pass
close enough to the nucleus of the atom to convert some of the
projectile e- kinetic energy to EM energy Because of the
electrostatic force?
28. Bremsstrahlung Radiation
29. Characteristic Radiation 2Steps Projectilee- with high
enough energy to totally remove an inner-shell electron of the
tungsten target Characteristicx-rays are produced when outer-shell
e- fills an inner-shell void Alltube interactions result in a loss
of kinetic energy from the projectile e-
30. It is called characteristic because it is characteristic
ofthe target element in the energy ofthe photon produced
31. X-ray energy Characteristicx-rays have very specific
energies. K-characteristic x- rays require a tube potential of a
least 70 kVp Bremsstrahlung x-rays that are produced can have any
energy level up to the set kVp value. Brems can be produced at any
projectile e- value
32. Discrete spectrum Contains only specific values
33. Continuous Spectrum Contains all possible values
34. Characteristic X-ray Spectrum Characteristic has discrete
energies based on the e- binding energies of tungsten
Characteristicx-ray photons can have 1 of 15 different energies and
no others
35. Characteristic X-RaySpectrum
36. Bremsstrahlung X-raySpectrum Brems x-rays have a range of
energies and form a continuous emission spectrum
37. Factors Affectingthe x-ray emission spectrum Tubecurrent,
Tube voltage, Added filtration, Target material, Voltage waveform
Thegeneral shape of an emission spectrum is always the same, but
the position along the energy axis can change
38. Quality And Quantity ??
39. mAs A change in mA or s or both results inthe amplitude
change of the x-rayemission spectrum at all energies The shape of
the curve will remain thesame
40. mA increase from 200 to 400
41. kVp A change in voltage peak affects boththe amplitude and
the position of thex-ray emission spectrum
42. Target Material The atomic number of the targetaffects both
the quantity and quality ofx-rays Increasing the target atomic
numberincreases the efficiency of x-rayproduction and the energy
ofcharacteristic and bremsstrhlung x-rays
43. Target material
44. Voltage Waveform 5 voltage waveforms:
half-waverectification, full-wave rectification, 3-phase/6-pulse,
3-phase/12-pulse, andhigh-frequency. Maintaining high voltage
potential