Lec 2 Main Features of Xray Tubehead

Question 1

The glass x-ray tubehead consists of? (3)

Answer 1

1. Filament
2. Copper block
3. Target

Question 2

Required to step-up the mains voltage of 240 volts to the high voltage (kV) required across the X-ray tube.

Answer 2

Step-up transformer

Question 3

Required to step-down the mains voltage of 240 volts to the low-voltage current required to heat the filament.

Answer 3

Step-down transformer

Question 4

To minimize leakage.

Answer 4

Surrounding lead shield

Question 5

To facilitate heat removal.

Answer 5

Surrounding oil

Question 6

To remove harmful low-energy (soft) X-rays.

Answer 6

Aluminium filtration

Question 7

A metal disc or cylinder with central aperture designed to shape and limit the beam size to a rectangle (the same size as an intraoral image receptor) or round with a maximum diameter of 6 cm.

Answer 7

Collimator

Question 8

A device for indicating the direction of the beam and setting the ideal distance from the focal spot on the target (the focus) to the skin.

Answer 8

Spacer cone / beam-indicating device

Question 9

A long focus-to-skin distance (fsd) of ________ should be employed, although focus-to-skin distances of _______ are increasingly being used.

Answer 9

NOT less than 20cm;
30 cm