Exam style Questions

Question 1

Radionuclides decay exponentially

Answer 1

True

Question 2

Radionuclides do not occur naturally

Answer 2

False

Question 3

Concerning DR, the receptor dose indicator gives a record of patient dose

Answer 3

True

Question 4

In automatic mode fluoroscopy, the patient ESD rate usually increases with image intensifier field size

Answer 4

False

Question 5

In automatic mode fluoroscopy the patient ESD should ideally be under 50mGy/min

Answer 5

True

Question 6

IRR- overall responsibility for keeping dose ALARP tests with practitioner

Answer 6

False (employer)

Question 7

IRR- the practitioner is the only person that can authorise exposures

Answer 7

False (skilled operators)

Question 8

For MRI Signal to noise ratio to be increased, what are the few things that will have to decrease?

Answer 8

1. TE
2. Receiver bandwidth

Question 9

Typical wavelength of ultrasound in abdominal scanning (in soft tissue) is 0.5mm

Answer 9

True

Question 10

CT SNR increases when kvs is decreased

Answer 10

False
KV and SNR are proportional

Question 11

Gadolinium should be avoided during the first trimester

Answer 11

True
Avoid in all stages of gestation

Question 12

K space is a table of spatial frequencies

Answer 12

True

Question 13

Each horizontal line of K space represents data from each frequency encoded gradient applied

Answer 13

False
It’s each phase encoding Gradient applied

Question 14

Information from the edge of K space corresponds to contrast of the image

Answer 14

False
Fine detail at the edges

Question 15

Noise is related to the square root of the number of photons

Answer 15

True

Question 16

Contrast is usually T1 weighted

Answer 16

True

Question 17

The larger the anode angle the larger the focal spot size and the less heat loading there is

Answer 17

True

Question 18

I’m CT scanners the anode-cathode axis is placed along the xy plane

Answer 18

False
Z plane

Question 19

Photomultiplier tubes take light produced by scintillation layers, from X-rays or gamma rays, and convert them into electric signal

Answer 19

True

Question 20

The gamma camera PMT tube is filled with inert halogen gas

Answer 20

False

Question 21

The effective dose is usually lower than the absorbed dose

Answer 21

True

Question 22

Compton scatter is the predominant mode of interaction in the input screen of the image intensifier

Answer 22

False
Photoelectric dominates due to high atomic number of CSI

Question 23

Compton scatter is the dominant mode of interaction on soft tissue with nuclear medicine studies

Answer 23

True
Average kv is high

Question 24

Increasing kVP from 40 to 60 will require mA to be reduced by approx a half to deliver the same dose?

Answer 24

True
60^2 / 40^2 = 2.25, so mA must decrease by factor of about 2.

Question 25

The spatial resolution of indirect FPDs is restricted by screen blur

Answer 25

True

Question 26

Spatial resolution in DR increases with pixel depth

Answer 26

False, decreases with pixel size Pixel depth determines number of X-rays that can be recorded

Question 27

I’m fluoroscopy, magnification mode improves both contrast and spatial resolution

Answer 27

True, at expense of increased dose

Question 28

Xray image contrast is improved by reducing the area of the X-ray beam

Answer 28

True

Question 29

Using an anti scatter grid with a higher grid ratio improves Xray spatial resolution

Answer 29

False Improves contrast not resolution

Question 30

Spatial resolution of Xray images is improved by decreasing patient to image receptor distance

Answer 30

True Reduced geometric unsharpness penumbra

Question 31

Spatial resolution of Xray images is improved by increasing the amount of added filtration on the beam

Answer 31

False This affects contrast and dose, not SR

Question 32

DRLs should be reviewed annually

Answer 32

True

Question 33

Dose rate from scattered radiation at 1m from patient is approx 0.1% of the dose rate incident on the patient

Answer 33

True

Question 34

Leakage radiation from Xray tubes must not exceed 1mGy/hr at 1m from the focal spot

Answer 34

True

Question 35

Spatial resolution in CT can be improved by reducing scan time

Answer 35

True Less motion artefact

Question 36

Noise from a CT study will increase with increasing matrix size

Answer 36

True Smaller pixels so decreased SNR

Question 37

The main role of the collimator of a gamma camera is to reject scatter

Answer 37

False True for X-rays but not for gamma. Scatter rejection is performed by PHA window. The collimator is for spatial localisation.

Question 38

TC99m emits energy rays of 140keV

Answer 38

True

Question 39

Contrast in planar nuclear medicine is dependent on the type of collimator used in the gamma camera

Answer 39

False

Question 40

SPECT scans are acquired using high resolution collimator

Answer 40

True They are needed to make up for the shitty resolution

Question 41

An uptake time of 30mins is used to prevent excessive decay of FDG

Answer 41

False it’s 60mins

Question 42

Tissue concentration of fDG is proportional to injected dose and inversely proportional to body weight

Answer 42

True

Question 43

Radiation dose from a radio pharmaceutical May be measured by a gamma camera

Answer 43

False The camera only visualises activity distribution, not doze

Question 44

On average around 0.4mSv per year of irradiation is due to medical exposures

Answer 44

True

Question 45

USS waves have a wavelength of 1-5mm in soft tissue

Answer 45

False It’s 0.3-1mm

Question 46

Muscle has a higher acoustic impedance than fat

Answer 46

True

Question 47

Increased operating frequency will result in improved axial resolution (USS)

Answer 47

True Improves both axial and lateral resolution

Question 48

An increased operating frequency will result in no change in the speed of USS wave propagation

Answer 48

True Speed depends on medium

Question 49

An increased operating frequency will give reduced incidence of aliasing in Doppler

Answer 49

False Results in more Doppler shift so more chance of aliasing

Question 50

MRI spin echo- the spin echo signal appears at time TE after the 90 degree pulse

Answer 50

True

Question 51

Gradient recalled echo sequences are affected by main field inhomogeneities

Answer 51

True

Question 52

Chemical shift artefact occurs along the frequency encoding axis gradient

Answer 52

True

Question 53

The anode angle is generally 7-20 degrees

Answer 53

True

Question 54

If the anode angle is reduced, the tube rating is…?

Answer 54

Increased

Question 55

The anode angle determines the size of field covered by the cray beam at a given…

Answer 55

Focus film distance