Questions

Question 1

frequency and wavelength are directly proportional eachother

Answer 1

true

Question 2

in vacuum velocity of radio waves is equal to the infrared light

Answer 2

true

in vacuum they all travel at the speed of light.

Question 3

visible light has a shorter wavelength than UV light

Answer 3

false

UV light is further up the spectrum and therefore has a shorter wavelength.

Question 4

electromagnetic radiation includes beta particles

Answer 4

false

beta particles are emitted from the nucleus.

Question 5

velocity of electromagnetic adiation increases as energy increases

Answer 5

False

The frequency increases as the energy increases, the velocity is constant.

Question 6

Ionising radiation may require only to be shielded with Perspex

Answer 6

Beta radiation may require only Perspex shielding, optimal shielding is achieved with Perspex backed with lead.

Question 7

Re secondary electron

They can interact with inner shell electron causing ionisation

Answer 7

False

They interact with outer shell electron

Question 8

In radioactive decay

Emission of beta- particle reduces atomic no by 1

Answer 8

False

N–> p+ B-

Z +1

Question 9

In radioactive decay

Positron emission reduces the number of protons by 1

Answer 9

True

P= n+ B+

Z-1

Question 10

Re radioactivity

If stored long enough the radioactivity will drop to zero

Answer 10

True

Although decay is an exponential process, all of the atoms will eventually decay

Question 11

Gamma rays are emitted at a single photon energy

Answer 11

False

More than one photon energy may be emitted

Question 12

Direct emission from radioactive decay includes

Beta minus
Characteristic x Ray
Bremsstrahlung 
Alpha particle
Positron emission

Answer 12

True
True
False
True
True

Question 13

Radiation output from x Ray tube increases with:
Increasing cathode to anode distance
Addition of filter
Increasing kv
Increasing mA
A constant potential compared to a single phase waveform

Answer 13

False- no relation 
False- decreases total output
True- output ~kv2*
True- output~ mA 
True- kv is near its max for longer

Question 14

In x Ray tube the anode angle is generally 20-30 degrees

Answer 14

False

The angle is generally 7-20

Question 15

The spectrum of the x Ray beam
Is not affected by filtration
Varies with tube current
Has a max energy determined by peak tube potential kvp
Consists of bremsstrahlung and characteristic radiation if kvp exceeds the k edge energy of the anode

Answer 15

False. Filtration removes low energy photons hardening the beam and increasing the mean energy of the spectrum
False. Increasing mA increases no of photons. The shape of spectrum remains the same if kv is unchanged
True.
True. Bremsstrahlung is the continuous spectrum and characteristic radiation the peaks specific to anode material

Question 16

Re x ray tube filament

It must have a high melting point and low resistance

Answer 16

False

High melting point and high resistance to generate heat for thermionic emission

Question 17

The anode heel effect is more noticeable at the cathode end of tube

Answer 17

False

It’s anode heel effect

Question 18

Increasing tube kv increases:

Patient entrance surface dose
Scattered compared to primary radiation at the film
Radio graphic contrast
Film blackening
Photoelectric compared to Compton

Answer 18

True
True. Higher kv x Rays are more penetrating
False. Contrast decreases as kv increases
True. Increased kv = increased exposure and increased film density
False. At higher kv Compton are favoured

Question 19

Attenuation of x Rays

Increased tube filtration increases the HVL

Answer 19

True

Total beam hardening

Question 20

HVL
Is a measure of penetrating power of x ray beam

For lead is greater than for Al
Is reduced as the photon energy of radiation decreases
Will produce exponential attenuation

Answer 20

True
False. The hvl decrease as the atomic number increases
True
True

Question 21

The MAC is less for water than for ice

MAC measured incm2*/g

Answer 21

False

It is equal for water a ice as it is independent of physical density

Question 22

LAC
it is the fractional reduction in intensity per unit thickness

It increases as the photon energy increases

It is measured in mm

Answer 22

True

False , it decreases as the photon energy increases

False, 1/mm

Question 23

Re scattered radiation

More is measured in the Tyneside of patient.

During a Compton interaction a photoelectron is produced

At higher kv more photons are deflected through large angles

Answer 23

True- most interaction occurs at the entrance surface of patient and forward scattered are more attenuated than back scattered ones.

False. These are formed in photoelectric int.

False. There is slight increase in forward scatter as kv increases, therefore there are more small angle deflections.

Question 24

Re photoelectric process

It may result in scattered radiation

Answer 24

False

There will be complete absorption

Question 25

Re absorption edge

At photon energies just above the k shell binding energy of an element there is a sharp decrease in the probability of photoelectric interaction

Answer 25

False

There is a sharp increase in the probability is photoelectric interaction

Question 26

Re absorption edge

An X-ray filter does not transmit photon well if they are of an energy equivalent to its own k absorption edge

Answer 26

False

It will be transparent