XRAY TUBE.pptx

x ray tube

1. X-Ray Imaging System Prepared By: Lalaine Joy Ridad , RRT,MSRT

2. TWO GENERAL TYPES OF X-RAY Examination Radiography Fluoroscopy Prepared By: Lalaine Joy Ridad, RRT

3. X-ray imaging system has three principal parts: The Operating Console The X-ray Tube The High-voltage Generator . Prepared By: Lalaine Joy Ridad, RRT

4. OPERATING CONSOLE allows radiologic technologists to control the x-ray tube current and voltage so that the useful x-ray beam is of proper quantity and quality Line Compensator Incorporates a meter to measure the voltage provided to the unit and control to adjust the voltage to precisely 220V Prepared By: Lalaine Joy Ridad, RRT

5. OPERATING CONSOLE Radiation quantity - refers to the number of x-rays or the intensity of the x-ray beam. - usually expressed in milligray (mGya) or milligray/milliampere-second (mGya/mAs). Radiation quality - refers to the penetrability of the x-ray beam Prepared By: Lalaine Joy Ridad, RRT

6. kVp Adjusment The console usually have adjustment labelled MAJOR MINOR selecting combination of these controls, the technologist can provide required kVp Prepared By: Lalaine Joy Ridad, RRT

7. mA Adjustment control The quality of electrons emitted by the filament is determined by the temperature of the filament controlled by filament current Increase Current=increase Heat=increase Thermionic Emission Currents of 50, 100, 200,300 mA and higher Prepared By: Lalaine Joy Ridad, RRT

8. The X-Ray Tube Has 2 primary parts (each are electrodes It is a Diode A diode is an electronic device that allows one way direction to the electric current to flow (DIRECT CURRENT) Prepared By: Lalaine Joy Ridad, RRT

9. 3 External Structures of X-Ray Tube Help easily position the x-ray tube. Ceiling Support System Floor-to-Ceiling Support System C-Arm Support System Support Structure Protective Housing Metal or Glass Enclosure 3 methods of X-Ray Tube support Prepared By: Lalaine Joy Ridad, RRT

10. Ceiling Support System Consist of 2 perpendicular ceiling-mounted rails Telescoping columns connects the tube to the railings Transverse Travel Longitudinal Travel Prepared By: Lalaine Joy Ridad, RRT

11. C-Arm Support System Commonly used in Interventional Radiology suites Ceiling-mounted tubes to provide flexible tube positioning The IR rest on the other side of the C Prepared By: Lalaine Joy Ridad, RRT

12. Protective Housing Prevents excessive leakage radiation Provide mechanical support to the x-ray tube Protects against electric shock Contains DIALA OIL - Prepared By: Lalaine Joy Ridad, RRT

13. Glass or Metal Enclosure` Glass made of pyrex glass that can withstand tremendous heat Enclosure maintains the VACUUM (No AIR)- Coolidge Tube Semi-evacuated (w/ AIR) – Crookes Tube Tube is 30-50 cm long , 20 cm in diameter Prepared By: Lalaine Joy Ridad, RRT

14. Glass or Metal Enclosure Glass Enclosure Pyrex glass Able to withstand tremendous heat generated Disadvantages: More likely to fail Lesser tube life Prepared By: Lalaine Joy Ridad, RRT

15. Glass or Metal Enclosure Metal Enclosure Maintain constant electric potential between the electrons of the tube current & the enclosure Advantages: -Less likely to fail -Longer tube life Prepared By: Lalaine Joy Ridad, RRT

16. STATOR STATOR ROTOR Rotating Anode (Head) CATHODE (-) ANODE (+) Filament Focusing Cup Prepared By: Lalaine Joy Ridad, RRT

17. Internal Components: Cathode Thoriated Tungsten -high atomic number (74) -high melting point (3410 c) - thermal conductivity Thermionic Emission -boiling off of electrons caused by sufficiently high current in the filament Prepared By: Lalaine Joy Ridad, RRT

18. Internal Components: Cathode Has 2 major parts: Focusing Cup Filament Filament -coils of wire -2 mm in diameter -1 or 2 cm long -produces electron by thermionic emission -1%-2% of thorium added to prolong tube life Prepared By: Lalaine Joy Ridad, RRT

19. Thermionic Emission A phenomenon where in the current through the filament is sufficiently high, the outer-shell electrons of the filament atoms are “boiled off” and ejected from the filament. Prepared By: Lalaine Joy Ridad, RRT

20. Internal Components: Cathode Focusing cup -Made up of Nickel (-) -Electrostatically confines electron cloud to a small area in the anode Prepared By: Lalaine Joy Ridad, RRT

21. Internal Components: Cathode Dual Focus Tube has 2 Focal Spot Large Focal Spot: - 1-1.5 mm -used for high heat required Small Focal Spot -0.1 -0.5 mm -used for high-resolution image Prepared By: Lalaine Joy Ridad, RRT

22. Focusing cup focuses the electrons to the focal spot with the use of its negative charge. Because of the negative charge of electrons, they tend to move away from each other based on the concept of magnetism Prepared By: Lalaine Joy Ridad, RRT

23. Anode 3 functions of Anode: Electrical Conductor Mechanical Support Thermal Dissipater (99% of electron’s kinetic energy=heat; 1% of electron’s kinetic energy= x-rays) Prepared By: Lalaine Joy Ridad, RRT

24. Target Made up of Rhenium-Tungsten -high atomic number (74) -high melting point (3410 c) - thermal conductivity-desipate heat effectively Prepared By: Lalaine Joy Ridad, RRT

25. Why Tungsten is the material of choice for the target? 1. Atomic number — Tungsten’s high atomic numbe. 2. Thermal conductivity —Tungsten has a thermal conductivity nearly equal to that of copper. 3. High melting point – Tungsten 3400°C melting point 1100°C for copper Prepared By: Lalaine Joy Ridad, RRT

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27. Anode Assembly Two types of anode: Stationary Anode Rotating Anode Anode is the positive part of the x-ray tube Prepared By: Lalaine Joy Ridad, RRT

28. Anode Assembly Stationary Anode: Used in Dental X-ray & other low tube current and power is required Rotating Anode: Revolves 3,400-10,000 rpm Anode angle range from 7-20 deg Provides larger target area that doesn’t confine heat in one area (754mm ) 2 Prepared By: Lalaine Joy Ridad, RRT