Questions Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

frequency and wavelength are directly proportional eachother

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

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

A

true

in vacuum they all travel at the speed of light.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

visible light has a shorter wavelength than UV light

A

false

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

electromagnetic radiation includes beta particles

A

false

beta particles are emitted from the nucleus.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

velocity of electromagnetic adiation increases as energy increases

A

False

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Ionising radiation may require only to be shielded with Perspex

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Re secondary electron

They can interact with inner shell electron causing ionisation

A

False

They interact with outer shell electron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

In radioactive decay

Emission of beta- particle reduces atomic no by 1

A

False

N–> p+ B-

Z +1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

In radioactive decay

Positron emission reduces the number of protons by 1

A

True

P= n+ B+

Z-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Re radioactivity

If stored long enough the radioactivity will drop to zero

A

True

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Gamma rays are emitted at a single photon energy

A

False

More than one photon energy may be emitted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Direct emission from radioactive decay includes

Beta minus
Characteristic x Ray
Bremsstrahlung 
Alpha particle
Positron emission
A
True
True
False
True
True
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

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

A
False- no relation 
False- decreases total output
True- output ~kv2*
True- output~ mA 
True- kv is near its max for longer
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

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

A

False

The angle is generally 7-20

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

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

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Re x ray tube filament

It must have a high melting point and low resistance

A

False

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

17
Q

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

A

False

It’s anode heel effect

18
Q

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
A

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

19
Q

Attenuation of x Rays

Increased tube filtration increases the HVL

A

True

Total beam hardening

20
Q

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

A

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

21
Q

The MAC is less for water than for ice

MAC measured incm2*/g

A

False

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

22
Q

LAC
it is the fractional reduction in intensity per unit thickness

It increases as the photon energy increases

It is measured in mm

A

True

False , it decreases as the photon energy increases

False, 1/mm

23
Q

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

A

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.

24
Q

Re photoelectric process

It may result in scattered radiation

A

False

There will be complete absorption

25
Q

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

A

False

There is a sharp increase in the probability is photoelectric interaction

26
Q

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

A

False

It will be transparent