Unit 4 wk 15 Flashcards
Radiology
branch of medicine that uses the application of radioactive substances to prevent, diagnose, and treat disease
What is the biochemical effect x-rays have on human tissues?
losing electrons/ionization
what type of image is a true negative
fluroscopic image because the background is white
Radiodensity
how much radiation is being absorbed from the xray beam
what are the 5 shades of grey
air - black
fat - greyblack
water-grey
bone- white
what are the ABCS search pattern for radiograph
alignment
bone density
cartilage spaces
soft tissue
CT
high resolution thin slices of axial anatomy
radiograph vs CT
radiograps have a fixed xray tube and one beam going through pt
CT: xray tube moves around patient and receptors measure remanent radiation
WHat is a TAP (thorx-abdomen-pelvis) scan?
eval of high risk trama pts for life threatening injuries in one quick exam
advantages of CT
fast image acquisition
soft tissue and osseous structure
view large portion of body
BEST IN EMERGENCIES (intracranial bleeds)
disadvantage of CT
most radiation exposure
T1 vs T2 weighted sequence (for MRI)
T1 defines anatomy
T2 detects fluid (H2O)
signal intensities in MRI – HIGH vs LOW
High = brighter image
Low = darker image
benefits of US
non invasive
no known ill effects
real-time- information
scanning planes of radiographs vs CT/MR
radiographs: AP, Lat, oblique
CT/MR: coronal, sagittal, axial
optimal use for each– CT, mri, US
US: cartilage, peds, soft tissue
MRI
CT