Bioimagingg Flashcards
Bioimaging as catalyst
open heart surgery replaced with minimally invasive operation
Bioimaging
methods that enhance vision
-smaller ,inside things ,highlight structure
bioimaging basic metrics
-resolution
-penetration depth
-contrast
-signal to noise
Resolution
smallest length difference you can image
contrast
can you tell two regions apart
low
optimum is the best
high
signal to noise
how clearly can you detect signal
related to contrast and resolution
Bioimaging modalities
-Electromagnetic
.optical; white light
.optical:florescence
.X-ray/CT
-Acoustic:soound
.ultrasound
-hybrid
.Photoacoustic tomography
white light Microscopes
simplest/oldest imaging technique
benefits= easy to use, fast
cheap
limits= theoretical resolution limit
enhancment = Endoscope
-camera+fiber optic cable
-fiber takes light to end of scope and back to camera
-Examine internal system
-used in surager to see into incision
Enhancements:
micotome
- machine to make thin slices
- good for Histology (analyzing tissue structure not analyzing function
enhancement=staining
stain to see cells
many different stains available
Fluorescense microscopes
-certain proteins will fluoresce when excited by light
-report location when stuck by light
fluorescent marking
stains-Fluorophores attached ti molecu
fluorescent taggged antibodies-Antibodies that carrry fluorophores will attach only with specifi target molecules
Gene expre-modification of genes can result in cells producing proteins that are fluorescent
can truck gene acrivity and movement of produced protein
x-ray
-X-rays are aborbed/scattered differently by different parts of body
-Detecting trasmitted X-rays create a picture of what is within object
Enhancemtn=Tommgraphy
Tomo=from greek for slice or section
Tomography- looking at slices of an object without destroging it
CT(Xray and tomography)
Xray images circles around patient to get slice
issues with x-ray
-ionizing radiation
-Dose-total xray absorbed
short exposure large area/target small area
-contrast ration-signal/noise
Contrast agent to reduce dose
high atomic number material to bring out contrast
-allows for lower dose because easier to see structure
MRI
-uses strong magnet to align molecules
-secondary perpendicular filed causes them to rotate at a frequency that depend on atomic characteristics
-release filed molec emit radio frequency waves that can detect
-radio frequency waves can be reconstructed to from 2D and 3D images
MRI factors
Good resolution
low risk(non-ionizing)
slow
Magnetic material (implant cannot go into MRI)
Ultrasoind ( Acoustic tomograph
-Uses sound(pressure wave)
-sound reflect off (echoes)interface
-measuring time between echoes tells how far the interface is from the detector
Ultrasound
pro=fast, cheap,low risk
con=low penetration
low resolution
only detects differences in density
Photoacoustic
Input-electromagnetic
output-sound
-low risk,better resolution and depth
-heat up the objects in the body when cool emit sound
Photoacoustic
-Attach mole that are sensitive to light to active agents
-when the agent get to area use light to trigger marker and see signal
