imaging Flashcards
what is an x ray
an electromagnetic packet of energy
extremely short wave length between 0.1 and 10 nanometres
how is an x-ray made
electron gun fires high energy electrons at a heavy atom
the collision creates breaking radiation in the form of X-Rays
how is it captured
the x rays are targeted at the patient and pass through on to the film - contains silver highlide will clump when activated
what is the best use for a CT
detailed images of
internal organs
blood vessels
bones
what is the best use for MRI
detailed images of most tissues
basic principle of ultrasound
fires sonic waves
scans soft tissue
good and bad bits of ultra sound
strengths - portable
inexpensive
weaknesses - can penetrate bone
operator dependents
good and bad bits of ultra sound
strengths - portable
inexpensive
weaknesses - can penetrate bone
operator dependents
what is the basic principle of a CT
2D x rays around a single axis to create a 3D image
what are the strength and weaknesses of CTs
strength - scans can be view in the sagittal, axial or coronal plane
weakness - cancer chance
reaction to contrast dye
what is the basic principle of fluoroscopy
used to obtain real time moving images
basicalp its an x ray source and a florescence screen and the patient is in the middle
what are the strengths and weaknesses of fluoroscopy
strengths - moving images
weaknesses - exposed to ionisation radiation and x-rays
what dose a iodinated contrast medium do
enhances visibility of vascular structures and organs during radiographic procedures
what is the problem with iodine
how is this comabtes
nephrotoxic - kidney failures
extra fluids are give after to flush out the iodine
what is iodinated contrast a form of
IV radiocontrast contain iodine
what are the attenuating factors from lowest to highest
Air Fat Muscle Bone Metal implants/CONTRATS
why on a x-ray do tissue have different appearances
due to the absorption of x rays
leats absorbed is air, fat, muscle then most absorbed is bone
what is ionising radiation
a particle or wave with sufficient energy to ‘ionise’ a neutral atom or molecule
gives them a positive or negative charge
what are the hazards of ionising radiation
lead to the disruption of chemical bonds within living tissue
free radicals and cancer
