Intro to radiography

Question 1

What is the role of diagnostic imaging?

Answer 1

Role of diagnostic imaging is to provide anatomical and physiological information which is achieved by producing a high quality image

Question 2

Steps involved in x-ray interactions with matter

Answer 2

-The incident photon is absorbed by K-shell electron (which is then displaced
-The vacancy is filled by an L-shell electron(resulting in Kalpha emission)
-The scattered photon has less energy than the incident photon and may be scattered through any angle.
-The Compton electron(aka the recoil electron) always scattered in a forward direction.

Question 3

What are 3 examples of image receptors

Answer 3

-Analogue-film based
-Computed radiography
-Digital radiography-built into the equipment

Question 4

X-ray attenuation

Answer 4

-X-ray beam is homogenous
-Patients act as absorbers
-The denser the structure the more x-rays are absorbed therefore the less energy is incident to the receptor
-Less energy incident to receptor produces a dark area on the image
-Routinely:
-White on an x-ray equals dense structures like bones
-Black on an x-ray equals lucent(non-dense) structures like air
-Various shades of grey, each grey level is a different level of attenuation within the body

Question 5

What type of image is it after x-ray attenuation

Answer 5

The picture is a differentiated x-ray energy level image

Question 6

What does plain film radiography use and what are the energy levels between?

Answer 6

-Uses ionising radiation
-Energy levels between 55 and 150 kVp as normal

Question 7

Projections in plain film radiography

Answer 7

-2 projections at 90 degrees to each other

Question 8

What does plain film radiography show?

Answer 8

-Joints- Centre over the joints
-Long bones-include joint on either end
-Include soft tissue
-Demonstrate bony tissue well and some soft tissue structures

Question 9

What energy level do they use up to for fluoroscopy?

Answer 9

They use X-rays up to 150 kVp

Question 10

What does fluoroscopy produce?

Answer 10

-Produces real time moving images

Question 11

What does fluoroscopy enable?

Answer 11

-Enable invasive, diagnostic, therapeutic and surgical procedures
-Cardiac, neuro, urinary

Question 12

What contrast agent is used in fluoroscopy and what are the possible problems?

Answer 12

Uses radio-opaque contrast agents
-iodine based-can be injected or ingested
-Can cause allergic reactions-Anaphylaxis
-Can have adverse drug interactions-Metformin

Question 13

What does fluoroscopy show

Answer 13

Bony tissue and some soft tissue structure

Question 14

What power of radiation does CT use?

Answer 14

Uses ionising radiation up to 150 kVp

Question 15

What type of image does CT produce and what was it known as before?

Answer 15

-Produces cross sectional images as standard
-Was known as computed axial tomography(CAT)

Question 16

What can be done to the acquired image from a CT scan in terms of planes?

Answer 16

-Acquired image data can be reconstructed in all planes

Question 17

What dimension image can a CT scan image present as?

Answer 17

-Can be presented as a 3D image

Question 18

What does a CT scan have a higher sensitivity to?

Answer 18

-Higher sensitivity to changes within the densities of the body

Question 19

What can a CT scan demonstrate after computer enhancement process

Answer 19

-Can demonstrate both bone and soft tissue using computer enhancement processes

Question 20

What can CT scan be used to assess in the cranium?

Answer 20

-Can be used to assess ‘new bleeds’ in the cranium

Question 21

What type of energy does MRI use

Answer 21

uses non ionising enery

Question 22

What does a MRI scan produce?

Answer 22

-Produces ‘multi planar’ images

Question 23

How does a MRI work?

Answer 23

-Works on the abundance of hydrogen in the body (H20)
-Utilises magnetic waves and sound waves to produce a signal
-Needs RF and magnetic shielding
-Signal is picked up and converted in to the image

Question 24

What does an MRI demonstrate and not demonstrate very well?

Answer 24

-Can demonstrate soft tissue very well-due to the water content
-Does not demonstrate hard bones well due to little water content

Question 25

What type of energy does ultrasound use?

Answer 25

Uses non ionising radiaiton

Question 26

What is an ultrasound?

Answer 26

-High frequency sound waves

Question 27

What is an ultrasound utilised for?

Answer 27

-Utilised for soft tissue imaging

Question 28

How does ultrasound work?

Answer 28

-The sound waves penetrate the structure and are reflected back
-The image is built up from the reflected sound waves

Question 29

What is doppler in ultrasound used for?

Answer 29

-Doppler is used to calculate blood flow

Question 30

What can colour in an ultrasound image be used for?

Answer 30

-Colour can be overlaid to enhance the clarity of image

Question 31

What energy does nuclear medicine/ radionuclide imaging use?

Answer 31

-Uses ionising radiation- gamma rays

Question 32

How does nuclear medicine/ radionuclide imaging work?

Answer 32

-Radioisotope is injected, inhaled or ingested by the patient
-The isotope is attached to a pharmaceutical that is targeted for the anatomical region
-Gamma rays are detected by the gamma camera and the image is constructed by the computer
- Goes to the area of highest activity (highest function)
- higher the activity the darker the blob

Question 33

What does radionuclide imaging demonstrate?

Answer 33

-RNI demonstrates functions and physiology mainly