Xray Tube Components

tube components, anode heel effect, line focus principle, off focus radiation, and tube loading

What is the role of the glass envelope

maintains a vacuum

What is the role of the tube housing

provides shielding and protection from radiation

What end of the tube has the filament and focusing cup

Cathode end of the tube

What are the types of anodes

stationary and rotating anodes

what is the anode made of

Typically made of tungsten and rhenium alloy

Whys is that anode material used? What are the benefits?

Tungsten and rhenium are chosen for their high melting points and excellent thermal conductivity, allowing for effective heat dissipation and prolonged lifespan in x-ray tube operation.

What is a stator?

rotates the anode, and is located outside the xray tube housing

What does the rotor do

It generates the rotating magnetic field, which drives the anode in the x-ray tube.

What do the bearings do?

They support and reduce friction for the rotating anode.

Define anode heel effect

increased exposure on the cathode side and decreased exposure on the anode side due to the geometry of the x-ray tube.

Why is the beam more intense on the cathode end

because of the angled anode

If the degree of anode angle decreases, will that increase or decrease the anode heel effect?

It will increase the anode heel effect, leading to greater differences in exposure between the cathode and anode sides.

Define line focus principle

the technique of angling the anode target to concentrate the x-ray beam and reduce the effective focal spot size, thereby enhancing image sharpness.

Which is larger, actual focal spot or effective focal spot

The actual focal spot is larger than the effective focal spot, which is created by the angling of the anode target.

Where is the actual focal spot located

on the anode target surface.

Does the effective or actual focal spot go toward the patient

The effective focal spot is the one that is directed toward the patient during an X-ray procedure.

If you decrease anode angle (small focal spot) how will that affect the effective focal spot?

It will increase the size of the effective focal spot, resulting in a larger area of radiation directed toward the patient.

Define off focus radiation

X-rays that are produced outside the main focal spot area on the anode

Define Tube Loading (heat units)

The measurement of the thermal energy generated in an X-ray tube during operation which indicates the allowable limits for the tube's safe use.

Formula for tube loading

mA X kVp X S x factor