RAD 105 Midterms: X-ray Production and Types of X-ray Tubes

These flashcards cover key concepts about X-ray production and components related to X-ray tubes, including their parts, functions, and types.

What are the components of the cathode in an X-ray tube?

The cathode consists of the filament, connecting wires, and a metallic focusing cup.

What is thermionic emission?

Thermionic emission is the release of electrons from the heated filament.

Why is tungsten used in X-ray tubes?

Tungsten has a high atomic number of 74, a high melting point (3422°C), and is a good thermionic emitter.

What does the Space Charge Effect refer to?

The Space Charge Effect refers to the cloud of electrons formed around the filament, inhibiting further release of electrons.

What is the purpose of the focusing cup in an X-ray tube?

The focusing cup, made of molybdenum or nickel, is negatively charged to focus electrons towards the anode and prevent spatial spreading.

What is the Line Focus Principle?

The Line Focus Principle results in a wider actual focal spot for heat dissipation, while maintaining a narrow effective focal spot for better resolution.

What happens during the Anode Heel Effect?

The Anode Heel Effect causes less x-ray photons to be produced on the anode side, as photons pass through the heel of the anode.

What is the function of the copper rotor in a rotating anode?

The copper rotor, driven by magnetic induction, helps to reduce friction and allows the anode to rotate at high speeds.

What is the role of the glass envelope in the X-ray tube?

The glass envelope is a thin enclosure that withstands high heat, prevents the production of secondary electrons, and allows x-rays to exit.

How does tube shielding improve safety in X-ray production?

Tube shielding blocks unwanted radiation, protects individuals in the room, and improves image quality by reducing scattered radiation.

What is the significance of rectification in X-ray production?

Rectification converts AC to DC, ensuring electrons flow from cathode to anode only, which affects the x-ray spectrum and output.

Describe the characteristics of characteristic radiation for tungsten.

Characteristic radiation for tungsten occurs when electrons transition between energy levels, with energies of 59.3 keV (Kα) and 67.6 keV (Kβ).

What is the importance of filters in the X-ray tube?

Filters attenuate low-energy x-ray photons that contribute little to imaging and primarily increase the entrance surface dose (ESD).

What are the steps in X-ray production?

1. Electric current heats the filament. 2. Electrons are released via thermionic emission. 3. Voltage is applied. 4. Electrons speed up towards the anode. 5. Electrons hit the anode, releasing energy. 6. X-rays are produced. 7. X-rays exit through the window. 8. X-rays pass through the patient.

What types of X-ray tubes are mentioned in the notes?

Types of X-ray tubes include mammography tube, angiography tube, CT X-ray tube, dental X-ray tube, microfocus X-ray tube, and radio-therapy tube.