X rays generators and transformers

DR SHARIQ A SHAH RADIODIAGNOSIS SKIMS SRINAGAR

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

2. WILHEM CONRAD ROENTGEN

3. 1985

4. X RAY TUBE

5. BREMSTRAHLUNG RADIATION

6. CHARACTERISTIC RADIATION

7. 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 Transformers Diodes and rectifier circuits Filament circuits kilovolt and milliampere meters.

8. COMPONENTS OF A GENERATOR

9. ELECTROMAGNETIC INDUCTION

10. TRANSFORMERS

11. Vp.Ns = Vs.Np

12. AUTOTRANSFORMER

13. DIODES

14. RECTIFIER CIRCUITS

15. FILAMENT CIRCUIT

16. FILAMENT CURRENT Vs TUBE CURRENT

17. GENERATORS Several designs of x-ray generators of varying complexity and cost are currently in use: Single-phase generator Three-phase generator Constant potential generator High-frequency generator.

18. SINGLE PHASE GENERATOR

19. VOLTAGE RIPPLE

20. Three-Phase Generators

21. 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

22. Two Types of 3 Phase Generators: 6 Pulse 12 pulse.

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

24. 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 .

25. 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.

26. 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.

27. 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 .

28. THANK YOU