Imaging in Cancer

Question 1

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

Answer 1

Plain radiographs

Barium studies

CT

MRI

PET

Question 2

What are conventional cancer diagnosis methods?

Answer 2

Endoscopy and biopsy

Barium examination

Question 3

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

Answer 3

Barium sulphate

Question 4

Why is barium used to outline the GI tract?

Answer 4

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

Question 5

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

Answer 5

1:2000

Question 6

What are different kinds of cross sectioning imaging?

Answer 6

CT

MRI

PET

Question 7

What can cross sectioning imaging be used for?

Answer 7

Initial diagnosis

Staging of the disease

Monitoring response after treatment

Evaluation of residual mass after treatment

Question 8

What does CT stand up for?

Answer 8

Computed tomography

Question 9

What happens during a CT scan?

Answer 9

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

Question 10

What is hounsfield unit?

Answer 10

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

Question 11

What are some common hounsfield values?

Answer 11

Air -1000

Lung -700

Fat -100

Water 0

Blood +40

Muscle +40

Calcium +150

Bone +700 to +3000

Question 12

What is a voxel?

Answer 12

A value on a grid in a 3D space

Question 13

What are contrast agents?

Answer 13

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

Question 14

What are the two kinds of contrast agents?

Answer 14

Oral

Intra-venous

Question 15

What do oral contrast agents do?

Answer 15

Outline the GI tract

Question 16

What do intra-venous contrast agents do?

Answer 16

Show blood vessels and vascularity of different tissues

Question 17

What are contrast agents usually made of?

Answer 17

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

Question 18

What are oral contrast agents known as?

Answer 18

Gastrografin

Question 19

What are IV contrast agents known as?

Answer 19

Omnipaque

Question 20

What do scans show to diagnose and stage a tumour?

Answer 20

Position of tumour

Depth of tumour

Relationship to adjacent structures

Involvment in regional lymph nodes

Presence of distant metastasis

Question 21

What are different scans used for?

Answer 21

Different kinds of cancers

Question 22

What kinds of cancers are CT scans used for?

Answer 22

Lung

Pancreatic

Renal

Adrenal

Retroperitoneal

Brain

Question 23

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

Answer 23

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

Question 24

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

Answer 24

Ensure examination is necessary

Adequate clinical information is essential for appropiate protocol

Avoid repeat examination

Question 25

What does MRI stand up for?

Answer 25

Magnetic resonance imaging

Question 26

How do MRIs work?

Answer 26

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

Question 27

What is MRI often used for?

Answer 27

Excellent soft tissue detail Vessels can be demonstrated Brain, spine and musculoskeletal Abdomen and pelvis Cardiac imaging

Question 28

What are disadvantages of MRI?

Answer 28

Claustrophobic and noisy Motion artefact Cannot image patients with pacemakers and other electronic implants

Question 29

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

Answer 29

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

Question 30

What is screening used for?

Answer 30

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

Question 31

What are the 3 NHS screening problem?

Answer 31

Breast Bowel Cervix

Question 32

What must happen for screening to be useful?

Answer 32

Condition should be an important health problem Should be a latent stage of disease Should be a test or examination for the disease Test should be acceptable to the population Should be a treatment for the disease

Question 33

What should screening do?

Answer 33

Detect disease at earliest stage Cause no harm High sensitivity and specificity Benefit to individual and population outweigh the cost