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Flashcards in Imaging in Cancer Deck (33)
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1

What are different kinds of imaging that can be used to diagnose cancer?

Plain radiographs

Barium studies

CT

MRI

PET

2

What are conventional cancer diagnosis methods?

Endoscopy and biopsy

Barium examination

3

What is a radio-opaque used from outlining the gastro-intestine tract?

Barium sulphate

4

Why is barium used to outline the GI tract?

High atomic number absorbs more X-rays than surrounding tissue and appears white on radiograph

5

What chance does barium have of developing fatal malignancy after 10 years latent perioid?

1:2000

6

What are different kinds of cross sectioning imaging?

CT

MRI

PET

7

What can cross sectioning imaging be used for?

Initial diagnosis

Staging of the disease

Monitoring response after treatment

Evaluation of residual mass after treatment

8

What does CT stand up for?

Computed tomography

9

What happens during a CT scan?

X-rays produce a digital image of a slice of tissue

10

What is hounsfield unit?

Attenuation value of voxels are expressed as a CT number which relates to the attenuation value to that of water (ranges from -1000 to +3000

11

What are some common hounsfield values?

Air -1000

Lung -700

Fat -100

Water 0

Blood +40

Muscle +40

Calcium +150

Bone +700 to +3000

12

What is a voxel?

A value on a grid in a 3D space

13

What are contrast agents?

Substances used to enhance the visibility of internal structures in X-ray based imaging

14

What are the two kinds of contrast agents?

Oral

Intra-venous

15

What do oral contrast agents do?

Outline the GI tract

16

What do intra-venous contrast agents do?

Show blood vessels and vascularity of different tissues

17

What are contrast agents usually made of?

Usually iodine based, oral ones are diluted and known as gastrografin and IV ones are known as omnipaque

18

What are oral contrast agents known as?

Gastrografin

19

What are IV contrast agents known as?

Omnipaque

20

What do scans show to diagnose and stage a tumour?

Position of tumour

Depth of tumour

Relationship to adjacent structures

Involvment in regional lymph nodes

Presence of distant metastasis

21

What are different scans used for?

Different kinds of cancers

22

What kinds of cancers are CT scans used for?

Lung

Pancreatic

Renal

Adrenal

Retroperitoneal

Brain

23

What CT scans have the highest equilvalent dose and what value is this?

CT scans of the abdomen and pelvis which have an equilvalent dose of 10mSv

24

What should be considered when deciding if a scan is required?

Ensure examination is necessary

Adequate clinical information is essential for appropiate protocol

Avoid repeat examination

25

What does MRI stand up for?

Magnetic resonance imaging

26

How do MRIs work?

1) Magnetic fields align protons in the body in one direction

2) Radiofrequency pulse displaces protons and images are created displaying the time they take to reurn to their original position

27

What is MRI often used for?

Excellent soft tissue detail

Vessels can be demonstrated

Brain, spine and musculoskeletal

Abdomen and pelvis

Cardiac imaging

 

28

What are disadvantages of MRI?

Claustrophobic and noisy

Motion artefact

Cannot image patients with pacemakers and other electronic implants

29

What contrast agent can be used in an MRI and what does this do?

Gadolinium DTPA (intravenous agent) which changes local magnetic fields and so alters the tissue signal

30

What is screening used for?

To diagnose at an earlier stage before symptoms begin, making it more curable