Flashcards in imaging in cancer Deck (20)
what are some imaging techniques that can be used in diagnosing and staging cancer?
(not imaging strictly) -endoscopy and biopsy
what colour does barium appear on the radiograph?
what would a barium swallow and meal allow us to look at?
oesophagus, stomach and duodenum
what would a barium enema allow us to look at?
what would a barium follow through allow us to look at?
how would a patient prepare for a barium meal and follow through?
fast for 4-6 hours
how would a patient prepare for a barium enema?
low residue diet for 48 hours and bowel cleansing
what happens in computed tomography (CT)
xrays produce a digital image of a slice of tissue, usually in an axial plane using computing to create the image
what is a voxel?
volume of tissue represented by a pixel in a CT slice
what is a hounsfield unit'?
the attenuation value of a voxel relative to the attenuation value of water
what contrast agents can be used in CT?
iodine based contrast agents can be used orally and intravenously
what factors are taken into account when diagnosing and staging cancer?
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)
what kinds of tumours are diagnoed using CT?
what is the radiation dose for chest, abdomen and pelvic CTs respectively?
chest - 8mSv
abdomen and pelvis - 10mSv
what does ALARA stand for?
as low as reasonably acheivable - aims to reduce number of exposures
what are the advantages of MRI?
excellent bone and soft tissue detail
vessels can be demonstrated
when would MRI use be indicated?
what are some contraindications of MRI?
claustrophobic and noisy
hard to image lungs
cannot image patients with metal implants
what is an example of a contrast agent used in MRI?
gadolinium DTPA - some tumours and vascular lesions can be more easily seen