Imaging in Cancer Flashcards Preview

Principles of disease JK > Imaging in Cancer > Flashcards

Flashcards in Imaging in Cancer Deck (24)
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1
Q

Name 5 Imaging techniques used in cancer

A

PET, CT, MRI, Barium studies and radiographs

2
Q

What is usually used for cancer imaging

A

Endoscopy and biopsy or barium examination

3
Q

What does barium sulphate do

A

Outline GI tract and does not react with tissues

High atomic number absorbs more xrays and appears white

4
Q

Barium swallow

A

Oesophagus

5
Q

Barium meal

A

Stomach and duodenum (1.5mSv) and fast for 4-6 hours

6
Q

Barium follow through/ small bowel study

A

Small bowel

7
Q

Barium enema

A

Large bowel (7mSv) and have a low residue diet for 48 hours and lie on left hand side

8
Q

CT

A

Xray Produce slice of tissue in axial plane

Fan shape beam of xray

9
Q

Hounsfield (HU)

A

Attenuation coefficient measurement

10
Q

HU of distilled water

A

0HU

11
Q

Sate some HU values

A
lung = -700
Fat = -100
blood = 40
muscle = 40
Calcium = 150
12
Q

Voxel

A

Value on a regular grid in 3D and position relative to other voxel

13
Q

Pixel

A

Physical point on an image (2D)

14
Q

Contrast agent

A

Oral ( dilute iodine to outline GI) or IV ( iodine for vascularity of tissues) but IV can have problems with anaphylaxis

15
Q

Explain the ways in which imaging can help with the diagnosis and staging of cancer

A
  • Presence of distant metastases and spread to lymph nodes
  • Relationship to adjacent structure
  • Position and depth of tumour and penetration
16
Q

CT radiation dose for chest

A

8mSv

17
Q

CT radiation dose for abdomen and pelvis

A

10mSv

18
Q

MRI and H+

A

Align H+ by strong magnetic fields in one direction

Radio frequency displaces protons and images created during the time protons take to relax and realign

19
Q

What is MRI used to see

A

Bone and fat
Soft tissue
Vessels and heart

20
Q

Drawback of MRI

A

Loud, noisy and claustrophobic
Can create a “ghost” due to fluid movement which can mimic pathology
Cannot image patients with pacemakers or aneurysm clips

21
Q

MRI contrast agent

A
Gadolinium DTPA (IV)
Changes local magnetic field and allows vascularisation and tumours to be seen easier
22
Q

Screening

A

Diagnose at earlier stage when asymptomatic eg cervix, lung, breast - mammography before lump felt but can give false positives

23
Q

WHO principles

A

The condition should be a important health problem and used at latent stage of disease

24
Q

Screening principles

A

Detect at early stage with no harm caused and should be highly sensitised and specific