Chapter 6 - X-ray Production, X-ray Tubes, And X-ray Generators

Question 1

Contains the electron source and target within an evacuated glass or metal envelope

Answer 1

X-Ray tube insert

Question 2

Provides protective radiation shielding and cools the X-Ray tube insert

Answer 2

Tube housing

Question 3

Supplies the voltage to accelerate the electrons

Answer 3

X-Ray generator

Question 4

Shapes the X-Ray energy spectrum

Answer 4

X-Ray beam filters

Question 5

Define the size and shape of the X-Ray field incident of the patient

Answer 5

Collimators

Question 6

SI UNIT OF POTENTIAL DIFFERENCE

Answer 6

Volt(V)

Question 7

Source of electrons

Answer 7

Cathode

Question 8

Target of electrons

Answer 8

Anode

Question 9

Probability distribution of X-Ray photons as a function of photon energy (keV)

Answer 9

Bremsstrahlung spectrum

Question 10

Shows an inverse linear relationship between the number and the energy of the X-rays produced

Answer 10

UNFILTERED bremsstrahlung spectrum

Question 11

Refers to the removal of X-rays by attenuation in materials that are inherent in the xray tube

Answer 11

Filtration

Question 12

Discrete X-ray energy peaks

Answer 12

Characteristic radiation

Question 13

Three major selectable parameters on the X-ray generator control panel that determine the X-ray beam characteristics

Answer 13

kV, mA and exposure time

Question 14

Product of the tube current and exposure time

Answer 14

mAs (milliamperes second)

Question 15

Angle of the target surface with respect to the central Ray (central axis) in the X-ray field

Answer 15

Anode angle

• typical range: 7 to 20 degrees
• most commonly used: 12-15 degrees

Question 16

Area of the anode that is struck by electrons and is primarily determined by the length of the cathode filament and width of the focusing cup slot

Answer 16

Actual focal spot size

Question 17

Foreshortening of the focal spot length at the central Ray

Answer 17

Line focus principle

Question 18

Refers to the reduction in the X-ray beam intensity toward the anode side of the X-ray field

Answer 18

Heel effect

Question 19

Results from electrons that scatter from the anode, and are re-accelerated back to the anode , outside of the focal spot area

Answer 19

Off-focal radiation

Question 20

Supports, insulates and protects X-ray tube insert from the environment

Answer 20

X-ray tube housing

Question 21

Removal of X-rays as the beam passes through a layer of material

Answer 21

Filtration

Question 22

Refers to sheets of metal intentionally placed in the beam to change its effective energy

Answer 22

Added filtration

Question 23

Most commonly used added filter material

Answer 23

Aluminum (Al)

Question 24

Used to Change the spatial pattern of the X-ray intensity incident on the patient, so as to deliver a more uniform X-ray exposure to the detector

Answer 24

Compensation (equalization) filters

Question 25

Principal function of an X-ray generator

Answer 25

To provide current at a high voltage to an X-ray tube

Question 26

Principal components of X-ray generators; they convert low voltage into high voltage through a process called ELECTROMAGNETIC INDUCTION

Answer 26

TRANSFORMERS

Question 27

A phenomenon in which a changing magnetic field induces an electrical potential difference (voltage) in a nearby conductor and in which a voltage is induced in a conductor moving through a stationary magnetic field.

Answer 27

ELECTROMAGNETIC INDUCTION

Question 28

The Voltage induced in the second winding is proportional to the voltage on the primary winding and the ratio of the number of turns in the two windings

Answer 28

Law of Transformers

Question 29

Increases the secondary voltage

Answer 29

Step up transformer

Question 30

Decreases the secondary voltage

Answer 30

Step down transformer

Question 31

Produces a secondary voltage equal to the primary voltage

Answer 31

Isolation transformer

Question 32

Basic electrical component that will allow current to flow in ONE direction only

Answer 32

Rectifier

Question 33

A device with two terminals

Answer 33

Diode

Question 34

Rate of energy production or expenditure per unit time

Answer 34

Power SI unit of power: watt (W) = 1 J of energy per second 1 watt = 1 volt X 1 ampere

Question 35

Electrical potential of the earth

Answer 35

Ground potential

Question 36

Difference between the peak voltage and the minimum voltage, divided by the peak voltage and multiplied by 100%

Answer 36

Voltage ripple

Question 37

Used as a safety mechanism to terminate the exposure in the event of an exposure switch or timer failure

Answer 37

Countdown timer (aka backup timer)

Question 38

Measure the actual amount of radiation incident on the image receptor and terminate X-ray production when the proper radiation exposure is obtained

Answer 38

Phototimer (aka Automatic exposure(AEC) control system)

Question 39

Power that an X-ray tube focal spot can accept or the generator can deliver

Answer 39

Power rating

Question 40

A traditional unit that provides a simple way of expressing the energy deposition and dissipation from the anode of an X-ray tube

Answer 40

Heat unit

Question 41

The penetrability of an X-ray beam

Answer 41

Quality

Question 42

Refers to the number of photons comprising the beam

Answer 42

Quantity

Question 43

5 factors affecting X-ray emission

Answer 43

1. Anode target material 2. Tube voltage (kV) 3. Tube current (mA) 4. Beam filtration 5. Generator wave form

Question 44

Common tools for measuring focal spot size (4)

Answer 44

1. Pinhole camera 2. Slit camera 3. Star pattern 4. Resolution bar pattern

Question 45

``` LARGE ANODE ANGLE SMALL FILAMENT LENGTH A. ______ field coverage B. ______ effective focal spot C. ______ power loading ```

Answer 45

A. large B. small C. poor

Question 46

``` LARGE ANODE ANGLE LARGE FILAMENT LENGTH A. ______ field coverage B. ______ effective focal spot C. ______ power loading ```

Answer 46

A. Large B. Large C. Good

Question 47

``` SMALL ANODE ANGLE LARGE FILAMENT LENGTH A. ______ field coverage B. ______ effective focal spot C. ______ power loading ```

Answer 47

A. small B. small C. good

Question 48

Increase in focal spot size resulting from high tube current (mA)

Answer 48

Focal spot "blooming" ***BLOOMING si mA

Question 49

Slight decrease in focal spot size with increasing kV

Answer 49

Focal spot "thinning" ***THIN KABA? (kV)