imaging anatomy Flashcards
(30 cards)
invasive medical procedures
instruments or objects into body
invasive imaging
-contrast is introduced
-injection of radioactive isotopes (PET)
-probe inserted
X-ray - what type of radiation
high-energy EM radiation
X-rays - denser the tissue the more radiation is absorbed/scattered
absorbed
common uses of X-rays
chest X-rays and mammograms
advantages and disadvantages of clinical x rays
advantages - easy to use - does not require a lot of image processing, produces quick results, painless NON INVASIVE
disadvantage - must be limited due to harmful radiation
PA x ray vs AP x ray
PA X ray - minimal distance between organ/tissue of interest and plate and aligned
how are modern x rays better to earlier models
-safer
-digital radiography - greater resolution
most common way to screen for tumours in chest and visualise main vessels around the heart
lateral chest X ray
single contrast study to outline the structure better in X rays
add radiopaque material such as barium that coats the wall of the lumen, outlining the structure better
double-contrast study to expand the lumen
add a gas
technique called …. combines use of radiopaque material over time by acquiring several images or recorded in film. MORE/LESS invasive than plain X ray
fluoroscopy
MORE
computed tomography (CT)= computerised x ray imaging
sending an a narrow beam of X rays at the subject while the machine quickly rotates around the body, getting multiple images
-computer combines all cross-sectional images TO PRODUCE 3D image
-tissue densities more apparent, tumours easily identified
-but more costly, results take longer
advantages and disadvantages of CT
advantages - basic tumours, tumours, abnormalities identified compared to plain x ray, tissue densities more apparent
disadvantages - more costly, more operator training, results take longer due to processing times
positron emission tomography - PET - imaging technique in nuclear medicine
-uses radioactive isotope to visualise metabolic processes - blood flow/bone formation
-radioactive isotope attached to a drug that travels to the tissue.
-as drug decays it collides with an electron in the tissue releasing gamma rays (energy)
-picked up by gamma camera to produce 3D image
CT and PET both produce
3D images
Positron Emission Tomography - scanner similar to CT - advantage and disadvantage:
-advantage - able to detect changes with time eg. tumour growth
-disadvantage - minimally INVASIVE as it requires an injection - costly
combined CT-PET - techniques are combined to explore
higher resolution of CT with time-lapse of PET
-tumours are precisely located, more accurate diagnosis
MRI derived from field of
NMR
MRI - found that:
magnetic nuclei eg. H if placed in a magnetic field & irradiated with radio waves at a specific frequency would absorb that energy
-nuclei then released energy after radio waves stopped
-NON -INVASIVE
2 forms of MRI which highlight specific tissues
T1 or T2 is chosen depending on what type of tissue the radiographer wishes to contrast more
what imaging provides the highest resolution
MRI
what imaging tool allows visualisation in real time
ultrasound - useful in diagnosis and management
-locating tissues
-sound beyond human hearing range
simplicity, portability and instant results
angiography -
visualising luminal structures eg. blood vessels or hollow organs
-provide contrasted vessels in brain X-rays to detect conditions such as tumours, artery disease, or vessel malformations
-INVASIVE - accessing large superficial vessel
-X ray angiography
-CT angiography uses a contrast
-MR angiography - DOES NOT need contrast
