X-ray generators are used to power x-ray tubes in radiology. They contain transformers, diodes, and circuits to select energy, quantity, and exposure time. Generators can be single-phase, three-phase, constant potential, or high-frequency. Three-phase generators provide a continuous output to reduce exposure time and improve image quality. Constant potential generators produce a near-DC waveform for more efficient acceleration of electrons.

1. X-RAY GENERATORS:
APPLICATIONS IN RADIOLOGY
SHARIQ A. SHAH
MODERATOR : PROF. MANJEET SINGH

3. WILHEM CONRAD ROENTGEN

6. 1985

12. X RAY TUBE

13. BREMSTRAHLUNG RADIATION

14. CHARACTERISTIC RADIATION

17. X RAY GENERATOR
• The x-ray generator delivers the electrical power to
energize the x-ray tube and permits the selection of
x-ray energy, x-ray quantity, and exposure time.
• Major internal components of the generator include
a) Transformers
b) Diodes and rectifier circuits
c) Filament circuits
d) kilovolt and milliampere meters.

18. COMPONENTS OF A GENERATOR

19. ELECTROMAGNETIC INDUCTION

20. TRANSFORMERS

21. Vp.Ns = Vs.Np

22. AUTOTRANSFORMER

23. DIODES

24. RECTIFIER CIRCUITS

26. FILAMENT CIRCUIT

27. FILAMENT CURRENT Vs TUBE
CURRENT

28. GENERATORS
• Several designs of x-ray generators of varying
complexity and cost are currently in use:
a) Single-phase generator
b) Three-phase generator
c) Constant potential generator
d) High-frequency generator.

29. SINGLE PHASE GENERATOR

31. VOLTAGE RIPPLE

32. Three-Phase Generators

33. • Voltage never drops to zero
• x-rays are continuously produced.
• Because of this exposure time can be dropped
as low as 1/1000 of a second.
• Disadvantages of three phase equipment:
1. Higher cost (twice as expensive as single
phase).
2. Size of the unit

34. Two Types of 3 Phase Generators:
a) 6 Pulse
b) 12 pulse.

35. Three Phase-Six Pulse
Uses six rectifiers, and one half of
the three phase AC pulses.
This generator give 360 pulses per second

36. Three Phase-Twelve Pulse-
• Uses twelve rectifiers, this gives 720 pulses
per second,
• It is more efficient than the six pulse but is
more expensive .

37. Constant Potential Generators
• Constant potential generators are so named
because of their ability to produce a high-voltage
waveform with essentially no voltage ripple
(essentially DC or “constant potential”).
• This is the preferred waveform, because the
electrons are accelerated at an even potential
difference throughout the exposure.
• A higher effective energy beam and greater tube
output is obtained with a DC waveform.

38. High-Frequency Inverter Generators
conversion of a low-frequency, low-voltage
input into a high frequency,low-voltage
waveform that producesa high-frequency,
high-voltage output waveform.

39. • In summary, the x-ray quantity is
approximately proportional to
Z target X kVp2 X mAs.
• The x-ray quality depends on the kVp, the
generator waveform, and the tube filtration.
• Exposure depends on both the quantity and
quality of the x-ray beam.