Imaging of cancer Flashcards Preview

Principles of dizzees > Imaging of cancer > Flashcards

Flashcards in Imaging of cancer Deck (20):
1

What structure in the body are barium contrasts primarily used to show?

Gastro-intestinal tract

2

How do contrasts, such as barium sulphate, appear on a radiograph?

White

(unless inversed image)

3

Although they're rarely used, what are barium enema's used to study?

Large bowel

4

What are the types of cross-sectional imaging methods?

MRI
CT
PET

5

In what plane do CT, MRI and PET scanners take images?

Axial (usually)

6

What are Hounsfield's units?

Attenuation values for x-rays, of different substances

Relative to that of water

7

Air has a Hounsfield unit of:

a) +1000
b) -1000

b ( -1000 )

If it's easy to pass through, it's negative

If it is denser/better at absorbing - positive

8

What natural substance in the body has the highest Hounsfield unit?

Bone

+700 to +3000

9

What is the difference between a pixel and a voxel, and what are voxels used for?

Voxel is in the 3D plane, pixel is 2D

Used in 3D constructions of images taken from CT scans etc

10

Describe the oral contrast that is used in CT scanning.

Dilute iodine based contrast

Called gastrografin

Outline gastrointestinal tract

Not used much nowadays - scanners more effective

11

What contrast agent is used intravenously in CT scanning?

Describe it's effectiveness

Iodine based contrast

Called omnipaque

Shows blood vessels and vascularity of different tissues

12

What risk is associated with the IV contrasts in CT's?

Risk of allergic/anaphylactic reaction

13

What is the difference between a T1 and a T4 tumour?

(Dont really need to know this in much detail)

T1 is small and hasn't really invaded/spread to much tissue

T4 has spread to adjacent tissues

14

Different sites of malignancy can be imaged using different techniques, for a variety of reasons.

What two sites of malignancy can only be imaged using MRI scanners, and not CT?

Spinal chord

Lymphomas of the CNS/MSK (not a 'site' but you get the point)

15

Aside from diagnosis, how is CT imaging used (in relation to cancers)?

Response to treatment

Checking for relapse

Checking progression of disease

16

What does ALARA stand for, and what is the ALARA principle used for?

'As Low As Reasonably Possible'

CT = fuck ton of x-rays = bad

To minimise risk of causing more harm (cancer) to the patient - examination should only be when:
- Necessary
- More information essential for appropriate protocol

Repeat examinations should be avoided

17

In MRI imaging, protons (H+) have their poles lined up with a strong magnetic field.

When they relax from this fixed alignment (and release energy), different molecules take a different amount of time to 'relax'.

What is the trend in the time taken to relax, and the molecular 'size'?

Heavier molecules - quick to relax

Lighter molecules - take longer

(Fat people are quicker to relax than fit, lighter people)

18

Describe the positives of MRI scanning?

Show bone and soft tissue in great detail

Show blood vessels

Imaging of the brain, spine, muscoloskeletal, abdomen, pelvis and cardiac

19

What is the main contrast used in MRI imaging?

Gadolinium DTPA

20

What cancers are screened for in the UK?

Breast
Colon
Cervical