SPECT Flashcards
what does SPECT stand for?
single photon emission computed tomography
what planes does SPECT use?
transverse, sagittal, and coronal
what is SPECT?
3d image acquisition done by cutting the bone into imaging planes
what are the benefits to SPECT?
- provide higher contrast than planar imaging
- no overlap of structures
- improved T:NP
- 3d cinematic representation of the organ
what are the benefits to SPECT/CT?
- combination of diagnostic tools to look at anatomy and function
- better lesion localization
- attenuation correction
- more confidence to making diagnosis
what is a con of spect/ct?
increased radiation dose to patient
for radiochemical purity, what is the desired complex for bone scans?
at least 90% tagged
what are the two contaminants that take away from having a ‘perfect’ tag?
- hydrolyzed reduced Tc
- free pertechnetate
100% tag means what for our images?
increase T:NT
where does free pert localize?
thyroid, breast milk, gastric mucosa, salivary glands
what is the difference between “continuous motion” and “step and shoot”?
continuous: acquisition of images with the camera constantly moving around the patient; no stops.
stop and shoot: when acquisition of images only happens when the camera stops at specific intervals around the patient
describe an elliptical orbit.
the ability to set two distances to adjust how close one camera will get from one region to another
describe a circular orbit.
used when imaging something more circular; allows for some regions to be closer to the camera than others
what is the kVp used for CT?
80-130
what is the mAs used for CT?
2.5-300
what is the matrix used for CTs?
512x512
how do you check for motion?
raw cine
what measures can you take as a technologist to limit the possibility of motion artifacts?
- communicate with the patient to not move
- adjusting scan time based on what the patient is capable of
- positioning the patient so they’re as comfortable as possible
what is CT alignment?
ensures nm images and ct images properly align
what are the 5 processing steps?
- motion correction
- ct alignment
- reconstruction
- reorientation
- image display
what is raw cine?
a short “movie” made of our 2d images
what are the two common reconstruction techniques?
- filtered back projection
- iterative
describe filtered back projection.
it is the simpler method – application of a high pass filter/ramp filter to limit star artifacts
describe the iterative method.***MLEM OSEM
which reconstruction technique is most often used for bone imaging?
iterative
which reconstruction technique produces higher quality images?
iterative
what is reorientation?
alignment of the image along the primary axis of the organ
do we typically need to do reorientation for bone scans?
no. unless the patient was positioned crooked on the bed
what can be displayed?
- reconstructed 3d image (can be cinematically)
- 2d slices
how are the the transverse slices displayed?
superior to inferior
how are the coronal slices displayed?
anterior to posterior
how are the sagittal slices displayed?
right to left
what views do we use to describe transverse images?
ANT/POST and R/L
what views do we use to describe sagittal images?
SUP/INF and ANT/POST
what views do we use to describe coronal images?
SUP/INF and R/L
what is an artifact?
structure or feature not normally present
what can cause artifacts?
equipment, RP, administration technique, imaging technique/patient prep
