Week 11 Flashcards
What are the 4 principles of xrays?
- xrays pass through the body - shadowed by calcium ion density
- Density differences - many shades of grey
- summation of shadows - images are created by multiple overlapping tissue densities
- Silhouette sign - edges of an object are only seen if there is an interface with a difference density tissue
What are the different density colours on an x-ray?
eg. what is black to white
More dense - more white (eg. metal)
Less dense - more black (eg air)
What is the best way to do a chest x-ray?
Posterior-anterior
though most patients get anterio-posterior cos they in bed
Why do you also need a lateral view on xray
to show depth
What are the 3 xray planes?
- coronal
- axial
- Saggital
How does an xray work?
xrays travel through body and is absorbed in denser tissues
What is a CT scan?
a combination of Xrays in slices
what is the CT rule of thumb?
If its unilateral it’s abnormal
What is MRI
Magnetic resonance imaging
it is able to detect small changes within soft tissues
patient is exposed to magnetic fields, not radiation
what are the MRI contraindications
- cerebral aneurysms clipped
- cardiac pacemaker
- inner ear implants
- metallic foreign bodies in and around the eyes
What is an angiogram
done with xray or MRI
- radiographic contrast is injected to differentiate between normal and abnormal tissues
What is nuclear medicine?
Uses radioactive substances to diagnose and treat. Looks at function not just structure
provides info about organ structure and function
commonly used with cancer patients
What is the most common nuclear medicine imaging?
PET scan
Positron emission tomography
How does ultrasound work?
- sound waves travel through different tissue at different speeds
- faster through dense material
What is POCUS?
Point of care ultra sound
