imaging in cancer

Question 1

what are some imaging techniques that can be used in diagnosing and staging cancer?

Answer 1

plain radiographs
barium studies
CT 
MRI
(not imaging strictly) -endoscopy and biopsy

Question 2

what colour does barium appear on the radiograph?

Answer 2

white

Question 3

what would a barium swallow and meal allow us to look at?

Answer 3

oesophagus, stomach and duodenum

Question 4

what would a barium enema allow us to look at?

Answer 4

large bowel

Question 5

what would a barium follow through allow us to look at?

Answer 5

small bowel

Question 6

how would a patient prepare for a barium meal and follow through?

Answer 6

fast for 4-6 hours

Question 7

how would a patient prepare for a barium enema?

Answer 7

low residue diet for 48 hours and bowel cleansing

Question 8

what happens in computed tomography (CT)

Answer 8

xrays produce a digital image of a slice of tissue, usually in an axial plane using computing to create the image

Question 9

what is a voxel?

Answer 9

volume of tissue represented by a pixel in a CT slice

Question 10

what is a hounsfield unit’?

Answer 10

the attenuation value of a voxel relative to the attenuation value of water

Question 11

what contrast agents can be used in CT?

Answer 11

iodine based contrast agents can be used orally and intravenously

Question 12

what factors are taken into account when diagnosing and staging cancer?

Answer 12

position of tumour
depth of penetration of tumour
relationship to adjacent structures - SIZE (T)
involvement of regional lymph nodes (N) 
presence of distant metastases (M)

Question 13

what kinds of tumours are diagnoed using CT?

Answer 13

pancreatic
renal
adrenal
retroperitoneal
brain

Question 14

what is the radiation dose for chest, abdomen and pelvic CTs respectively?

Answer 14

chest - 8mSv

abdomen and pelvis - 10mSv

Question 15

what does ALARA stand for?

Answer 15

as low as reasonably acheivable - aims to reduce number of exposures

Question 16

what are the advantages of MRI?

Answer 16

excellent bone and soft tissue detail

vessels can be demonstrated

Question 17

when would MRI use be indicated?

Answer 17

brain
spine
musculoskeletal
abdomen
pelvis
cardiac imaging

Question 18

what are some contraindications of MRI?

Answer 18

claustrophobic and noisy
hard to image lungs
cannot image patients with metal implants

Question 19

what is an example of a contrast agent used in MRI?

Answer 19

gadolinium DTPA - some tumours and vascular lesions can be more easily seen

Question 20

what should screening tests aim to acheive?

Answer 20

should detect disease at an early stage where treatment can alter outcome
test should cause no harm
test should have high sensitivity and specificity
benefit to individual and population should outweigh the cost