Medical Imaging

Question 1

What is radiology?

Answer 1

A branch of medicine concerned with the use of radiant energy or radioactive material in the diagnosis and treatment of disease

Question 2

What is the difference between a radiologist and a radiographer?

Answer 2

A radiologist is a doctor who interprets images whereas a radiographer is someone who is trained to take the images

Question 3

What is interventional radiography?

Answer 3

Medical sub-specialty of radiology utilising minimally-invasive image guided procedures

Question 4

Give an example of invasive radiology

Answer 4

Angioplasty, insertion of a balloon into a vein or artery to widen it

Question 5

How does an X-ray create an image?

Answer 5

When the beam passes through the human body, some of the X-rays are absorbed or scattered producing reduction of the beam

Question 6

What is attenuation?

Answer 6

the reduction of the amplitude of a signal, electric current, or other oscillation

Question 7

How does different tissues effect attenuation?

Answer 7

The higher density of tissue causes more attenuation so will show up as lighter grey or white on an X-ray

Question 8

What are the five X-ray densities?

Answer 8

Air-Black
Fat-Dark grey
Soft tissue- Grey
Bone-Light grey
Metal-White

Question 9

Why is it important to take images on multiple planes?

Answer 9

The fracture,break and dislocation may be hidden by one viewpoint

Question 10

What is used to prevent radiation on certain body parts?

Answer 10

A metal screen, used primarily to stop radiation meeting the ovaries and testes

Question 11

How would you take an image of a patient’s heart?

Answer 11

Posteriarly to avoid magnification of the heart

Question 12

What is mammography?

Answer 12

Specific type of X-ray that uses low dosages which is designed for images of the breast

Question 13

What is fluoroscopy?

Answer 13

Type of medical imaging that shows a continuous X-ray image on a monitor

Question 14

When is fluoroscopy used?

Answer 14

When there is a need for real-time examination

Question 15

Give an example of when fluoroscopy is appropriate

Answer 15

Implants during surgery, viewing movements of contrast agents

Question 16

How does fluoroscopy differ from a regular X-ray?

Answer 16

The image is displayed on a fluorescent screen

Question 17

What is angiography?

Answer 17

X-ray technique used in the examination of the arteries, veins and organs to diagnose blockages

Question 18

What is the process of an angiograph?

Answer 18

A thin tube is inserted into an artery or vein, then a contrasting agent is injected to make the blood vessels visible on the X-ray image

Question 19

What is tomography?

Answer 19

A method that produces images of single tissue plane

Question 20

What does CT stand for?

Answer 20

Computed tomography

Question 21

What does CAT stand for?

Answer 21

Computerized axial tomography

Question 22

What is a CAT scan?

Answer 22

Radiologic imaging that uses a computer to generate an image of the tissue density in a slice of the patient

Question 23

How should you envision yourself when seeing CAT scan?

Answer 23

The patient is on their back and your looking from their feet to their head

Question 24

What are the advantages of CAT scans?

Answer 24

Fast, readily available, good imaging of bony structures abdomen and lungs

Question 25

What are the disadvantages of a CAT scan?

Answer 25

High radiation dose, not so good at imaging soft tissue

Question 26

What is scintigraphy

Answer 26

Radioisotopes attached to drugs that travel to a specific organ or tissue are taken internally and the emitted gamma radiation is captured by external detectors to form two-dimensional images in a similar process to the capture of x-ray images

Question 27

What is the most commonly used radionuclide?

Answer 27

Technetium or 99mTc

Question 28

What does the term metastable mean and what does this allow?

Answer 28

The radionuclide atom has two basic energy states, as the atom transforms from the high-energy state to the low-energy state, it emits a quantum of energy in the form of a gamma ray

Question 29

What is single photon emission CT (SPECT)?

Answer 29

A scintigraphic technique whereby the the computer can detect subtle lesions overlain by other active structures

Question 30

How can a SPECT scan be improved?

Answer 30

Fusing it with a CT scan, this improves sensitivity and specificity

Question 31

What is a positron emission tomography (PET) scan?

Answer 31

A combination of computed tomography and scintillation

Question 32

How does a PET scan work?

Answer 32

An isotope is attached to a biological compound to form a radio-pharmaceutical, which is injected into the patient to from a 3D image

Question 33

What are the advantages of scintigraphy nuclear medicine?

Answer 33

Good functional information Good localization of pathology

Question 34

What are the disadvantages of scintigraphy nuclear medicine?

Answer 34

High radiation dose Not so good at differentiating between different pathologies

Question 35

What is a magnetic resonance imaging (MRI)?

Answer 35

A form of imaging that uses a powerful magnetic field and radiofrequencies to produce detailed images of the body'd internal structures

Question 36

How is the imaged created in an MRI?

Answer 36

When the radio signal is turned on, the energy is absorbed by different atoms is reflected back out of the body

Question 37

What are the three levels of signal intensity in a MRI?

Answer 37

High- white Intermediate- grey Low- black

Question 38

What are the two basic types of MRI images?

Answer 38

T1 and T2 weighted images

Question 39

Which type of MRI allows the image to see fat and water?

Answer 39

T2-weighted images

Question 40

Which type of MRI is better at identifying a tumour?

Answer 40

T2

Question 41

What are the advantages of MRI?

Answer 41

Gold standard of imaging No radiation Good localization of pathology Good differentiation between pathologies Excellent soft tissue imagine

Question 42

What are the disadvantages of MRI?

Answer 42

Strong magnet Not so good showing anatomy of bones Cost Long duration of scanning Need for anaesthesia in younger children/uncooperative patients

Question 43

Advantages of ultrasound?

Answer 43

Safe No ionizing radiation Relatively inexpensive

Question 44

Disadvantages of ultrasound?

Answer 44

Highly operator dependent Structures surrounded by bone cannot be seen Cannot be used for some tissues due to attenuation

Question 45

When should radiation be completely avoided?

Answer 45

In pregnant woman