Mock

Question 1

Please list the components within the cathode portion of the X-ray tube. Please discuss these components with regards to their properties and function.

Answer 1

Filament Coil - Tungsten. Current is passed through the coil; the Coil heats up and emits electrons (Thermionic Emission)
Focussing Cups - Nickle. Provides electrostatic focussing of the beam onto the anode—negative charge.
Vacuum - Helps to ensure electrons move uninterrupted across x-ray tube.

Question 2

What are the two types of radiation that are produced at the anode focal spot?

Answer 2

Bremsstrahlung and Characteristic Radiation

Question 3

Please define the following:
kVp
mAs
kEv

Answer 3

kVp: Kilovolt peak. Measure of the maximum electrical potential across an x-ray tube.
mAs: Milliampere- second. Product of exposure time and x-ray tube current or measure of the total number of electrons.
kEv: Kiloelectrons Volt. The kinetic energy of the electron is equivalent to 1000 eV (1000eV=1kEV_

Question 4

What effect does an increase of kVp have on the number of photons in the x-ray beam and their energy?

Answer 4

Increases the energy, has no effect on the number of photons beam.

Question 5

Please state the 5 main radiographic densites?

Answer 5

Air, Metal, Bone, Water, Fat

Question 6

Please state 5 properties of the x-ray?

Answer 6

No mass
Electrically neutral
Invisible
Travel at the speed of light
Highly penetrating
Travel in straight lines in a divergent beam
Diagnostic range of energy 15-150 keV
Cause certain substances to fluoresce
Can expose photographic film
Produce secondary radiation
can ionize matter

Question 7

What are 5 attenuation interactions that can occur between x-ray photons and matter, and which 2 interactions do we find in diagnostic radiography?

Answer 7

Coherent Scatter
Compton Scatter - Diagnostic Radiography
Photodisintegration
Pair production
Photoelectric Effect - Diagnostic Radiography creates energy and does not affect the number of photons in the beam.

Question 8

What is the name of the point on the anode target with which the electrons interact to produce the x-ray beam?

Answer 8

Focal Spot

Question 9

What thickness of Aluminium equivalent filtration must legally be manufactured into an x-ray tube?

Answer 9

2.5mm

Question 10

Please define ‘‘Grid Ratio’’?

Answer 10

The ratio of the height of the led strips to the distance between two strips (the interspace).

Question 11

Please state three advantages of utilising the air gap technique?

Answer 11

Reduction of surface skin entrance dose,
comparable to using a grid if one is not available,
reduces the amount of scattered radiation that reaches the image receptor,
improves the contrast resolution of the image.

Question 12

Please list the following in order of radiosensitivity, with the most radiosensitive at the top and the least radiosensitive at the bottom: Digestive System, Skin, Nervous System, Blood forming organs, Bone, Muscle, Reproductive System

Answer 12

Blood forming organs
Digestive system
Reproductive system
Skin
Bone
Muscle
Nervous system

Question 13

Please discuss the 10 Day Rule?

Answer 13

This applies to women of childbearing age, used for higher dose examination i.e. CT, RNI/PET, Need to establish the first day of the last menstrual period, if this is within the last 10 days then the examination can proceed, if its outside of 10 days then a pregnancy check may be performed.

Question 14

Please discuss 28 day rule?

Answer 14

This applies to women of childbearing age, used for low dose examination i.e. CT, RNI/PET, Need to establish the first day of the last menstrual period, if this is within the last 28 days then the examination can proceed, if its outside of 28 days then a pregnancy check may be performed.

Question 15

Please define the following:
Radioprotector-
Radiosensitiser-

Answer 15

Radioprotector- Agent that reduces the response of the cell to radiation.
Radiosensitiser- Agent that enhances the response of a cell to radiation.

Question 16

What dose DEXA stand for and what does measure?

Answer 16

Dual Energy X-ray Absorptiometry
Measures bone mineral density.

Question 17

What is the purpose of using filtration within an x-ray tube?

Answer 17

To reduce the low energy x-ray photons that will contribute towards patient dose, and harden beam.

Question 18

What is the name of the operator-dependent filtration that can be applied to an x-ray tube?

Answer 18

Compensatory filtration

Question 19

High-quality grids will attenuate approximately how much scatter radiation?
60-70%
70-80%
80-90%
90-100%

Answer 19

80-90%

Question 20

Please state 3 techniques that could be employed to reduce blurring on the radiograph?

Answer 20

Use the shortest possible exposure time.
Restrict patient movements by providing instructions or acceptable restraining techniques.
Use a large SID
Use small OID
Suspend Breathing Inspiration/Expiration

Question 21

What is DRL and DAP stands for?

Answer 21

DRL- Dose Reference Level
DAP - Dose Area Product

Question 22

Please state the 2 Cross section imaging modalities useful for musculoskeletal imaging?

Answer 22

CT- Computer Tomography and
MRI - Magnetic Resonance Imaging

Question 23

Please state 6 ways to reduce unnecessary radiation dose to patients?

Answer 23

No unnecessary examinations.
No repeat examinations.
Use lead shielding.
Good communication with the patient.
Ensure correct patient positioning.
Ensure appropriate radiographic technique applied.

Question 24

What imaging modality describes the appearance of tissue by their ‘‘echogenicity’’?

Answer 24

Ultrasound or Sonography

Question 25

What charge is Anode and Cathode?

Answer 25

Anode is Positive and Cathode is Negative

Question 26

What the energy range for diagnostic imaging photons?

Answer 26

15-150keV

Question 27

What radiation use CT?

Answer 27

Ionising radiation

Question 28

Please state when we should use the air gap technique?

Answer 28

Should only be use when an air gap is unavoidable i.e. lateral C-spine, HBL hip.
And when scatter must be reduced.
Can be used instead of an anti-scatter grid for some projections.

Question 29

Please state 4 common grid ratio’s?

Answer 29

4:1,6:1,8:1,10:1 or 12:1

Question 30

What technical factor primly controls image density?
What technical factor primarily controls image contrast?

Answer 30

mAs
kVp

Question 31

Please define ‘‘Shape Distortion’’ and give two examples of how this can occur?

Answer 31

Unequal magnification of different portions of the same objects.
Anatomy can be angled or image detector can be angled.

Question 32

Please discuss the difference between ‘‘Direct’’ and ‘‘Indirect’’ radiation damage?

Answer 32

Direct - radiation interacts directly with the critical target in the cell. Atoms within the cell can be ionised or excited, causing a chain of physical and chemical events. Dominant interaction of high LET particles
Indirect - Radiation interact with other molecules within the cell i.e. water, produces free radicals, which can damage the critical target in the cell. Accounts for approximately 2/3 of damage by low LET radiation.

Question 33

What legislation is primarily concerned with protecting patients within diagnostic radiography and imaging?

Answer 33

IRMER2017 - Ionising Radiation (Medical Exposure ) Regulation 2017

Question 34

What legislation is primarily concerned with protecting Staff and Public within diagnostic radiography and imaging?

Answer 34

IRR 2017 - Ionising Radiation Regulations 2017

Question 35

Please discuss the advantages and disadvantages of using MRI - Magnetic Resonance Imaging as additional modality?

Answer 35

Advantages - Can image pregnant patients, pathology characterisation, people can stay in the room, planning ability, comprehensive, accurate reconstruction.

Disadvantages - Medical risks, contrast risk, uncomfortable, expensive, misdiagnosis, claustrophobic, lengthy training and exam, waiting lists.

Question 36

What CT windows techniques have been applied to the following images?

Answer 36

Bone -300/200
Soft tissue -40/400
Lung window - -600/1600