WEEK 1

Question 1

What is the difference between Diagnostic Radiology and Therapeutic Radiology?

Answer 1

Diagnostic Radiology = uses various imaging modalities to aid in the diagnosis of disease
Therapeutic Radiology = uses radiation to treat diseases using a form of treatment called radiation therapy

Question 2

What is a CT scan and what is it used for?

Answer 2

Computed Tomography (CT) is a type of imaging that uses x-rays to make cross sectional pictures of your body.

It is used to look out for broken bones, lungs, brain, cancers, blood clots, signs of heart disease, internal bleeding and any acute problem e.g bleeding & trauma

Question 3

What is faster between a CT scan and an MRI?

Answer 3

CT (10-15sec) is FASTER than MRI (25-30min)

Question 4

What is the history of the discovery of X-Rays?

Answer 4

In November 8 1895, Wilhelm Conrad Röntgen (a German professor) discovered while experimenting with cathode tubes a new penetrating radiation and called it “X-Rays”.

The first historical X-ray image was of the hand of his wife & he got a Nobel prize for physics in 1901.

Question 5

Common equipment/techniques used in Diagnostic Radiology?

Answer 5

• CT (Computed Tomography)
• MRI (Magnetic Resonance Imaging)
• X-Ray
• Ultrasound

Question 6

What is an X-ray?

Answer 6

X-rays are electromagnetic radiations which are used to create images of the subject/body

Question 7

Why are X-ray images typically black and white?

Answer 7

X-ray images are black and white due to the different absorption of tissues

Question 8

What tissue absorbs X-rays the most and what colour would the tissue be seen as?

Answer 8

Bones, they will be seen as WHITE since calcium in bones absorbs x-rays the most

Question 9

What colour does healthy lungs appear in X-rays?

Answer 9

Black (because air absorbs X-rays the least)

Question 10

How does an MRI work?

Answer 10

MRI uses a large magnet and radio waves to look at organs and structures inside the body

Question 11

MRI is similar to a CT scanner in that produces __________ of the body

Answer 11

cross-sectional images

Question 12

How does the CT machine work?

Answer 12

The x-rays are produced in a part of the ring and the ring is able to rotate around the patient and create images

Question 13

Describe the radiography principle of image formation

Answer 13

1. X-ray beam of uniform intensity falls on object which consists of structures with different absorption properties
2. The different structures absorb the beam in different amounts
3. The transmitted beam consists of different intensities called the “aerial image”
4. The aerial image falls on the image receptor which translates to an image

Question 14

What are the common uses of x-rays?

Answer 14

• Broken bones/Fractures
• Pneumonia
• Breast cancer

Question 15

What is an MRI and what is it used for?

Answer 15

Magnetic Resonance Imaging (MRI) uses a large magnet and radio waves to look at organs and structures inside your body

MRIs can be used for:
- Diagnosing tumours
- Bleeding
- Blood vessel diseases
- Infection
- Brain and spinal cord
- Abdomen and pelvis
- Bones and joints

Question 16

What is another term for CT scan?

Answer 16

CAT scan

Question 17

When did the first MRI machines become available?

Answer 17

1980s

Question 18

What is the difference between T1 and T2 MRI?

Answer 18

T1 MRI is known as “Spin-lattice relaxation time” and differentiates fat from water (water appearing darker and fat appearing brighter). T1-weighted MRI is best for looking at brain structures.

T2 MRI is known as “Spin-spin relaxation time” and also differentiates from water but fat shows darker and water shows lighter. T2 is better for looking at non-enhancing brain lesions.

Question 19

What is the strength of magnets used in both T1 and T2 MRI?

Answer 19

0.5-2.0 Tesla range

Question 20

What are some limitations of using MRI?

Answer 20

• some patients experience claustrophobia
• some obese patients cannot be examined
• patients with pacemakers and metalwork cannot be examined

Question 21

What is ultrasound and what is it used for?

Answer 21

Ultrasound is a type of imaging that uses high-frequency sound waves to look at organs and structures inside the body

Ultrasound is used to view the heart, blood vessels, organs, tissues and muscles

[ultrasound cannot see bones or lungs but can see muscles. structures cannot be seen under the bone since ultrasound cannot penetrate through the bones]

Question 22

What frequencies are used in ultrasound diagnostics?

Answer 22

2-40 MHz with intensity of 1 kW/m^2