X-ray Tube Part 2 Flashcards Preview

Rad Physics II > X-ray Tube Part 2 > Flashcards

Flashcards in X-ray Tube Part 2 Deck (59):
1

2 principal parts of Induction Motor

Rotor
Stator

2

Outside part of the enclosure

Stator

3

Consists of series of electromagnets equally spaced around the neck of the tube

Stator

4

Stator may either be

Permanent magnet or
Electromagnet

5

An electromagnetic coil of copper wire that is connected to a power supply

Stator

6

Sends pulses of energy to the stator which in turn induces motion into the anode assembly

Rotor controller

7

Wire that transfers rotor controller to the stator

Stator cord

8

Shaft inside the enclosure

Rotor

9

Rotor is made of

Bars of copper and soft iron

10

Works through electromagnetic induction

Induction motor

11

Production of voltage across a conductor moving through a magnetic field

Electromagnetic induction

12

Covert electricity into mechanical energy

Electric motor

13

Current in each stator wirings induces

Magnetic field

14

Are energized sequentially so that induced magnetic field rotates on the axis of the stator

Stator

15

Short delay allows

The rotor to accelerate to its designated rpm while filament is heated

16

Where the high voltage electrons hit the anode

Focal spot

17

Focal spot is also known as

Target
Focus
Focal point

18

Area around the anode that is exposed to electrons

Actual focal spot

19

Area projected onto the patient

Effective focal spot

20

Impacts the geometric resolution of the X-ray image

Focal spot

21

Smaller the focal spot

Better spatial resolution

22

Designed incorporated into the X-ray tube targets allowing large area of heating while maintaining a small focal spot

Line Focus principle

23

Angling of the target

Line focus principle

24

Diagnostic tube target angles allows

5 to 20 degrees

25

Reduce the effective area of the focal spot

Line focus principle

26

Effective focal spot is controlled by

Size of the actual focal spot
Anode target angle

27

Electrons can rebound and interact with other areas

Off-Focal Radiation

28

Control of Off Focal Radiation

Diaphragm (place bet the tube)
Collimator (reduce off focus rays)

29

Produces two off focal spot sizes because of two diff target angles

Biangular Targets

30

Radiation intensity on the cathode side is greater than the anode side

Anode-Heel Effect

31

Heel effect is considered when

Positioning areas with diff thickness or density

32

Placed over the area if greater density

Cathode side

33

In full supine X-ray

Anode should be up
Cathode down

34

Under the control of radiologic technologist

X-ray tube life

35

Extended by using minimum radio graphic factors

Tube life

36

Three forms of tube cooling

Radiation
Convection
Conduction

37

Anode may glow red hot and emit infrared energy

Radiation

38

Heat is conducted through narrow molybdenum neck to the rotor assembly

Conduction

39

Glass enclosure raises temperature of the oil bath

Convection

40

Warming the anode through a series of exposure and increasing the kVp settings, the anode will build up heat

Tube warm-up procedure

41

Charts that guide radiologic technologist on the use of X-ray tubes

X-ray tube rating charts

42

Three types of X-ray tube rating charts

Radiographic rating chart
Anode cooling chart
Housing cooling chart

43

Conveys which radiographic technique is safe or unsafe

Radiographic rating charts

44

A guide regarding the most common technical factor combinations that can be used without overloading the tube

Radiographic rating charts

45

There are diff charts for

Filament use
Speed of the anode
Target angle
Voltage rectification

46

Given mA, any combination of kVP and time that lies below the mA curve

Safe

47

Lies above the curve

Unsafe

48

Has limited capacity for storing heat

Anode

49

Thermal energy is measured in

Heat units (HU)

50

Anode cooling chart: single-phase formula

HU = kVp x mA x time

51

Anode cooling chart: three-phase / high frequency formula

HU = 1.4 x kVp x mA x time

52

Heats in Joules formula

heat (J) = w x kVp x mAs

53

1 HU =

1.4 J

54

Used to determine the length of time required for complete cooling after any level of heat input

Anode cooling chart

55

Maximum of 350,000 HU

15 minutes to cool down

56

Tube housing have the capacity of ___ HU

1 to 1.5 million

57

Complete cooling of tube housing

1 to 2 hours

58

Permits the calculation of the time necessary for the housing to cool enough for additional exposures to be made

Housing Cooling charts

59

Turn the anode

Induction Motor