registry review Flashcards
body temp
96.8 - 100.4F/ 36.0 -38.0 c
pulse adult
60-110 beats per min
pulse infant
100- 160 beats per min
pulse children
95-110 beats per min
respiration adults
14-20 beats per min
respiration adolescents
18-22 beats per min
respiration children
22-28 beats per min
respiration infants
30 or greater
blood pressure
120/ 80mm hg
systolic pressure
peak pressure in arteries (contraction of heart)
diastolic pressure
lowest pressure in arteries (relaxation of heart)
oximetry
measures blood oxygen levels 95-100%
measure renal function
creatinie , BUN,GFR
creatinine
.5-1.7 mg/dl
BUN
6-22 mg/dL
radiologist must be consulted when BUN is ____ and creatinie is ____
greater than 30, greater than 2
GFR
90-120mL/ min
PTT (partial thromboplastin time )
25 to 35 sec
PT blood coagulation
12-15 seconds
INR (international normalized ratio)
.8-1.2
platelet count
140,000 -440,000
LFT ( liver function test) – bilirubin
.1-1.2mg/dL
anticoagulants
inhibit coagulation
anticoagulants names
Warfin (coumadin) , Heparin , Plavix, Aspirin
Less than____ of the dose of contrast is excreted into breast milk
1%
aseptic
when personnel use techniques to reduce infection during IV injection (wearing gloves)
sterile
when personnel are maintaining a sterile area which includes the area of interest and the area around it ( sterile drape in surgery )
a 20 gauge or larger is preferable for flow rates of ___or higher
3mL/s
KVP has a ____ relationship w/dose
direct and exponential : decrease w/ no change in other factors will decrease dose
mAs has a ____ relationship w/dose
direct as mAs increase dose to patient increases
Pitch with a single slice scanner
pitch above 1 decreases pt. dose (shorter scan time)
pitch with MDCT
increase in pitch increases image noise and increases dose to the patient
thinner slices ____ pt. dose
increase
prospective gating
ECG trigger which allows for pauses in radiation dose as oppose to continuous exposure
lead apron in CT should be
above or below patient , never inside the SFOV
bismuth shields should be placed
after scout image is taken can be placed in SFOV
CTDI dose index
calculation of the dose received by the patient during a CT scan or slice
axial, step ans shoot : CTDIw
dose measurements along the x and y axes
helical : CTDI vol
dose measurements for sections of CT obtain during helical scan x,y, and z-axis
MSAD (multiple scan average dose )
is an older term /method for calculating average cumulation of dose to the pt.
MSAD formula axial scans :
MSDA=T/I xCTDI
T= slice thickness I= incrementation
overlapping scans ____pt. dose
increase
gaps in scans _____pt. dose
decrease
MSDA formula helical scans
MSDA=CDTI/pitch
is controlled by pitch
dose length product
international measurement of CT pt. dose
DLP formula
DLP= CTDIvol x scan length DLP= MSAD x slice thickness(cm) z No. of slices in scan volume
dose notification
technical settings are higher than preset limits
dose alert
total dose for scan is higher than preset limits
azimuth
angle of x-ray tube in relationship to the pt. during a scan
the gantry houses :
generator , x-ray tube, collimators, DAS, slip rings , detectors
SSCT collimators
uses a fan or coned shaped x-ray beam
MDCT collimators
uses a cone-shaped x-ray beam
generator
high frequency
60 to 110 kilowatts (kW)
has a high voltages current needed to produce x-rays
the configuration of the x-ray tube to the detectors determine
scanner generation
3rd generation
fan beam, rotate-rotate
4th generation
fan beam, stationary circular detector , rotate only
2nd generation
fan beam , translate-rotate
1st generation
parallel beam , translate -rotate
5th generation
fan beam , high -speed CT scanning , EBCT
6th generation
multiple x-ray tubes/detectors
7th generation
tube/ detector coupled , flat -panel digital detectors , produce good spatial resolution but lack contrast resolution
ray
part of the x-ray beam that hits the detector (beams path)
ray sum
is the value given to that beam (calculation of it’s attenuation value- linear coefficient )
view (projection)
collection of rays sums
profile
systems ‘s calculation of all the ray sums received
prepatient collimation
determines the size of the focal spot
detector (post patient ) collimators
shape the beam and remove scatter
data channels
control the number of slices the system can obtain
array processor
is responsible for for receiving scan data processing it to produce the CT image ( applying reconstruction algorithms/kernels) and then sending it back to the computer where it can be seen and stored
preprocessing software
initial processing of the signal data received from the detectors (helps with beam hardening)
reconstruction software
mathematical applications applied to raw data to create an image ex. convolution, back projection , algorithms
postprocessing software
further changes to the processed data images to be seen in different planes
WW controls
contrast
WL controls
brightness
calcium score of 0
no evidence of plaque
calcium score of 1-10
minimal plaque
calcium score of 11- 100
mild plaque
calcium score of 101-400
moderate plaque
calcium score greater than 400
extensive plaque
reconstruction
raw data is used to create new images
reformation
when image data is used to produce images in different planes or to produce 3D images
image reformation is also called
image rendering
to reformat a CT study all source images must have identical
DFOV, image center ,gantry tilt, and they must be contiguous
reformations that is done to show anatomy in various planes
MPR
MPR
are 2D in nature . Unlike 3D displays , 2D image displays always represent the original CT attenuation values
CPR curved planar reformation
allows images to be created along the center line of tubular organs
surface rendering
images are created by comparing the intensity of each voxel in the data set to some predetermined threshold /ct value
MIP
selects voxels w/ the highest value to display
MinIP
selects voxels with the lowest value to display
volume rendering
3D semitransparent representation of imaged structure
all voxels contribute to the image allowing the image to display multiple tissues and show their relationship to one another
spatial resolution (high contrast resolution)
ability to see the difference in small structures which are close together
spatial resolution is measured in
line pairs per centimeter
factors that affect spatial resolution
focal spot size detector size reconstruction algorithm pixel dimension sampling frequency
contrast resolution (low contrast resolution)
ability to see the difference in 2 structures w/similar HU
factors affecting contrast resolution
subject contrast beam collimation algorithm selection window setting detector collimation noise
temporal resolution
the speed that the data can be acquired
noise
data (signal ) that doesn’t contain any useful information . only degrades the image (quantum, electronic system, artifactual)
signal to noise ratio (SNR)
measured w/water phantom
should be zero any other number noise is present
uniformity
the ability of the scanner to yield the same CT number regardless of the location of an ROI within a homogeneous object
linearity
refer to the relationship between CT numbers and linear attenuation values of the scanned object at a designated kVP value
measured by scanning special phantom that has multiple materials
