Module 3

Question 1

What is the atomic number Z

Answer 1

is the number of protons

in the nucleus

Question 2

What charge do protons have?

Answer 2

Positive charge

Question 3

What charge do electrons have

Answer 3

negative charge

Question 4

What charge do neutrons have?

Answer 4

None

Question 5

Isotope

Answer 5

protons and neutrons in the nucleus are not of equal number

Question 6

Radioisotopes

Answer 6

isotope with unstable nuclei which undergoes radioactive disintegration
(radioactive)

Question 7

What do eletrons do?

Answer 7

They orbit the nucleus in shells, each shell has

a different energy level

Question 8

K shell electron

Answer 8

has the least energy and is the nearest to nucleus

Question 9

How do electrons travel?

Answer 9

Electrons can jump from one shell to another
but cannot exist between shells (forbidden
zone)

Question 10

What is the forbidden zone

Answer 10

Between shells electrons cannot exist

Question 11

What is the electron binding energy?

Answer 11

Electrons are bound to the nucleus by

electromagnetic force

Question 12

Positive Ion is?

Answer 12

If an electron is removed the atom becomes

positively charged and becomes a positive ion

Question 13

Ionisation

Answer 13

The process of removing the electron from shell

Question 14

Excitation

Answer 14

If an electron is moved from an inner shell to an
outer shell the atom remains neutral this is called
Excitation

Question 15

electron volt (eV)

Answer 15

The unit of energy in the atomic system is called

the electron volt (eV)

Question 16

Heat Producing Collisions

Answer 16

The incoming electron is deflected by the cloud of
outer shell tungsten electrons with a small loss of
energy

Question 17

Heat Producing Collisions alternative

Answer 17

The incoming electron collides with an outer shell
tungsten electron displacing it to a peripheral
shell (excitation) or displaces it completely from
the atom (ionisation)

Question 18

X-Ray Producing Collisions

Answer 18

The incoming electron penetrate the outer electron
shell and passes close to the nucleus of the tungsten
atom. The incoming electron is dramatically slowed
down and deflected by the nucleus with a large loss of
energy which is emitted in the form of X-rays

Question 19

X-Ray Producing Collisions alternative

Answer 19

The incoming electron collides with an inner shell
tungsten electron displacing it to an outer shell
(excitation) or displaces it completely from the atom
(ionisation) with a large loss of energy and emission
of X-rays

Question 20

The two different types of x-ray collisions result

in different x-ray spectra

Answer 20

Characteristic spectrum

Continuous/ Bremsstrahlung spectrum

Question 21

Intensity peaks appear when

Answer 21

In the characteristic spectrum

Question 22

Kilovoltage (Kv)

Answer 22

Voltage across the tube determines the

quality of the beam

Question 23

increase the Kv the contrast is decreased

Answer 23

longer

grey scale and the dose is reduced

Question 24

Milliamperage (mA)

Answer 24

• Electrical current flowing through

the tube- determines the quantity of the beam

Question 25

What happens if you increase the mA

Answer 25

the image will be darker and the | higher the dose

Question 26

Time (s)

Answer 26

The duration of the exposure time increase the time the image will be darker and the dose will be higher

Question 27

Xray interactions with matter. What are the Four outcomes

Answer 27

``` Scattered Absorbed Attenuated The electrons do not interact and so are transmitted unchanged ```

Question 28

xray interactions with matter depends on

Answer 28

the amount of energy the photons possess

Question 29

Scattered

Answer 29

The electrons are deflected from their original path and carry on travelling in a different direction with no loss of energy.

Question 30

Absorbed

Answer 30

The electrons are absorbed with a total | loss of energy

Question 31

Attenuated

Answer 31

A combination of absorption and scattering which will reduce the intensity of the beam

Question 32

‘Photoelectric | effect’

Answer 32

Absorption – pure absorption

Question 33

‘Compton effect’

Answer 33

Attenuation – scatter and absorption

Question 34

The incoming photon and inner shell electron collide

Answer 34

The energy of the incoming x-ray photon needs to be equal to or greater than that of the binding energy for ejection to take place 69.5Kv

Question 35

The inner shell electron is ejected with considerable | energy into the tissues

Answer 35

this ejected electron is now called a photoelectrons (further interactions will take place with the photoelectrons)

Question 36

X-ray photon has deposited all its energy

Answer 36

pure | absorption – x-ray photon no longer exists

Question 37

Vacancy within the electron shell has to be filled

Answer 37

outer shell electrons fall in to replace ejected | photoelectron.

Question 38

The atom has to return to neutral state

Answer 38

it captures a free electron to achieve stability

Question 39

Soft tissue has an atomic number of

Answer 39

7

Question 40

Bone has an atomic number of

Answer 40

12

Question 41

Aluminium Z is

Answer 41

13

Question 42

Copper Z is

Answer 42

29

Question 43

Lead is used in radiation protection as Z is

Answer 43

82

Question 44

Low Energy Scattered Photons produce?

Answer 44

back scatter which may be absorbed by patient and may not leave body – lead provides no protection or can possibly trap them in the body

Question 45

High Energy Scattered Photons will produce

Answer 45

forward scatter, if it reaches film it will degrade the image but normally it is removed by an anti scatter grid

Question 46

The interaction of the photon hitting an electron is not | dependent on the Z number

Answer 46

very little diagnostic information as there is very little contrast produced on the radiograph