Previous Exam Guides Flashcards
QA program monitors
ppl
QC program is for
film processors, CT scanners, XR tubes
most QC testing on rad equipment is done
annually
all general purpose rad units must have a min. of _____ mm Al filtration
2.5
filtration is measured w _______ measurements
HVL
focal spot size is measured w
pinhole/star/slit camera
it is acceptable to perform a ______ test instead of measuring the focal spot size
line pair
the measured kVp should be +/- ____ of the kVp indicated on the console
10%
what is the testing device used to measure cassette screen-film contact?
wire-mesh
comparing the mR output ay 50 mA @ 0.2 sec, 100 mA @ 0.1 sec, & 200 mA @ 0.05 sec is part of a test for _______
linearity
when a light in a viewbox is out, then
bulb must be replaced, all bulbs in viewboq must be replaced, all bulbs must match adjacent viewboxes
processor crossover racks should be cleaned out on a _______ basis
daily
processors should be monitored every day for
densitometric measurements, water/chem temps, & replenishment tank levels
an artifact can be
an object that is not part of the XRed anatomy, pt motion, improper grid, or warped cassette
a ________ is an example of an exposure artifact
foreign object
a static mark artifact is created during ______ of the film
handling
what sort of artifact is a guide-shoe mark?
processing artifact
the largest # of repeat exams is generally caused by ________ types of artifacts
exposure
misalignment of the processor turnaround assembly can cause?
guide-shoe marks
thin lines on the leading/trailing edge of a film are
guide-shoe marks
a bi-color chem stain on an XR
curtain effect, or dichroic stain
low humidity in the darkroom can cause
tree static
a streak of high optical density on the finished XR can be caused by
light leaks in the cassette/darkroom
when a QC test for exposure linearity is performed, adjacent mA stations must be w/in this amount of one another
10%
when a QC test for exposure reproducibility is performed, successive exposures must be w/in this amount of one another
5%
when QC test for collimator accuracy is performed, result must be w/in this amount
2% of SID
when a QC test for accuracy of kVp is performed, the result must be w/in _____ of the control panel setting
10%
the accuracy of collimation at a 72” SID must be
+/- 1.44”
unwanted markings on a XR are called
artifacts
small marks on XR about 3.1416” apart are called
pi lines
when insufficient light is produced, the img will be grainy, a condition known as
quantum noise
the aspect of a film-screen system that may be examined by conducting a wire mesh test is the
film-screen contact
what can cause img blur on the finished XR?
pt motion
which artifact occurs when the grid lines are II to the laser lines in a CR?
Moiré
a math process of assigning a digi value to a dead pixel based on recorded values of adjacent pixel is known as
interpolation
the effect or irregular pattern (variations in img brightness) can be minimized by
flat fielding
a software correction that is performed to equalize the response of ea pixel to a uniform XR beam is known as
flat fielding
what is a histogram?
a plot of the frequency of appearance of a given object char.’s; a graph of frequency of occurrence v digital value intervals
about 80% of breast cancer occurs in
ductal tissue
it is recommended that women obtain their 1st baseline mammo before the age of
40
a target of Mo or Rh is preferable in mammo bc it reduces the?
scatter
breast compression has the advantage of lowering
pt dose, motion blur, & superimposition
breast compression is used to ____ pt dose, and _____ focal spot blur
lower, reduce
breast compression increases
contrast & spatial res.
mammograms are taken w _______ cassettes
single screen
mammography currently uses ______ film
single-emulsion
screening mammo requires _____ view(s) of ea breast, whereas diagnostic mammo requires _______ views
2, 2+
the ________ is responsible for supervising QA
chief radiologist
the purpose of QA program is to maintain max ________ w min _________
quality mammos, pt dose
the avg glandular dose to mammo pt’s must be tested annually by the
medical physicist
the team of _________________ is responsible for mammo QC
mammographer, radiologist, & medical physicist
the ________ is responsible for selecting the medical physicist & mammographers responsible for QC
radiologist
when is the QC eval of the equipment performed?
once a year or when major components are replaced
the role of a medical physicist includes
performing annual performance evals of equipment, consult w mammographers concerning QC, & review QC records to check for compliance
the mammographer should ________________ on a monthly basis
complete a visual checklist
how often should mammographer perform the QC test for screen-film contact?
semi-annually
during tomography the XR tube & IR move around an imaginary pivot point called the
fulcrum
the tomographic angle determines the
section thickness
as tomographic angle _______ the tomographic section _______
increases, becomes thinner
which structures are most blurred in a tomographic img?
structures farthest from fulcrum
heigh of fulcrum determines the
level of object plane
thickness of tomo layer is affected by ___________ of the tube
multidirectional movement & tomo angle
what is the formula for the magnification factor using img & object size?
MF = img size/object size
if the img size of an object is 3 cm and the MF is 1.5, then what is the actual object size?
2.0 cm
the radiologist has requested that the img for a cerebro angio be magnified 100%. where would you set the SOD of the head if the SID is set at 20”?
10”
what is the true size of a lesion if its magnified img measures 3 cm and the MF is 1.5?
2.0 cm
what is the formula for MF using the SID?
MF = SID/SOD
it is essential that a ___________ be used in magnification rad to preserve img detail
small focal spot
Mo produces char XRs w energy of ____ keV
19
Rh produces char XRs w energy of ____ keV
23
mammo uses a tube tilt of
6º
mammo uses an anode angle of
23º
in mammo, the total beam filtration should not be less than ____ mm of Al equivalent
0.5
which target material is best for mammo of a pt w thick dense breast tissue?
Rh
most mammo systems now have a moving grid w ratio of
5:1
the electronic noise in digital mammo can be reduced by
cooling the detector
a min of ________ mammon must be included in a repeat analysis
250
a wire mesh test must be performed
semiannually
tomo angle & slice thickness are
indirectly proportional
a tomo w a tomo angle of 10º or less is known as
zonography
a panoramic tomo is used to XR what structure?
mandible
which tube trajectory will produce the max blurring of the unwanted structures?
spiral
where is the AEC located in the mammo unit?
underneath the IR
which has the highest spatial res.?
screen film mammo
as the effect focal spot size increases, the spatial res. will
decrease
mammo uses grid frequencies of?
30-50 lines/cm
if the pt is halfway btw the IR and the focal spot, then the MF is
2
the output phosphor of the I.I. is composed of
zinc cadmium sulfide
the output phosphor of the I.I. converts _____ to _______
e-‘s, light
photocathode of I.I. convert _______ to _______
light, e-‘s
brightness of fluoro img depends on the following factors
anatomy being examined, kVp, mA
scattered rad in the form of XRs, e-‘s, & particularly light can reduce the contrast of I.I. tubes through a process called
veiling glare
____________ is the reduction in brightness at the periphery of the img
vignetting
in a 25 cm/17 cm/12 cm I.I. which mode will display max anatomy?
25 cm mode
in a 25 cm/17 cm/12 cm I.I. which mode will display the highest spatial res.?
12 cm mode
in a 25 cm/17 cm/12 cm I.I. which mode will cause the highest pt dose?
12 cm mode
compared to 25 cm fluoro mode; in a 12 cm fluoro mode, the focal point will?
move away from the output phosphor
how magnified is the img of a 36/25/12 I.I. in the 12 cm mode compared w the 36 cm mode?
3 x’s
what is the photoconductive layer of the I.I.?
target plate
what is the material used in the photoconductive layer?
antimony trisulfide
in DF, the spatial res. is limited by
pixel size
during DF, the under-table XR tube actually operates in the ________
radiographic mode (increased mAs)
in DF, the T required for the XR tube to be switched off is called ________
extinction T
in DF, the fraction of T that the XR tube is energized is called the ________
duty cycle
img-guided catheter navigation is possible w
FPIR
the SNR of DF is
1000:1
what produces a sharper img w less flicker (in fluoro)?
progressive mode
speed of img acquisition, processing & transfer to the output device is determined by
dynamic range of ea pixel, # of pixels, & storage method
what is the mA used during conventional fluoro?
0-5 mA
≤5 mA
ability of the eye to detect the differences in brightness levels is termed
contrast perception
the ____ in the retina are stimulated by ____ light
rods, low
cones, bright
XRs that exit the pt & enter the I.I. first interact w the ______
input phosphor
the input phosphor of the I.I. is composed of
cesium iodide (Ce-i)
the input phosphor converts _____ to _____
XR, light
the _______ in the I.I. emits e-‘s when it is stimulated by light photons
photocathode (thru photoemission)
the # of light photons emitted w/in the I.I. is ______ to the amount of XR photons exiting the pt
directly proportional
calculate the flux gain of an I.I. that is equipped w a 25 cm input phosphor & 5 cm output phosphor
cannot be calculated (need # of light in output and # of XR in input)
an I.I. has a 12 cm input phosphor and a 4 cm output phosphor. about 50,000 light photons were produced at the output phosphor when the input phosphor received 100 XR photons from the pt. calculate the total brightness gain.
4500
e-‘s hit the _____ after exiting the anode
output phosphor
the ______ is the product of the minification gain & the flux gain
brightness gain
the ratio of XRs incident on the input phosphor to light photons exiting the output phosphor is called
flux gain
capability of an I.I. to increase the illumination level of the img is called
brightness gain
an I.I. tube is identified by the diameter of its _____
input phosphor
fluoro for an air contrast barium enema is generally done at ___ kVp
80-90
viewing the fluoro img in magnification mode increases
contrast/spatial res. & pt dose
ABC maintains the brightness of the img by varying
kVp & mA
the T it takes to turn on the DF XR tube & reach the selected mA & kVp is the
interrogation T
a CCD used in DF provides high _______
spatial res, SNR, & detective quantum efficiency
a principal advantage of DF is the
img subtraction capability
DF systems w hybrid capabilities use both _______
temporal & energy subtraction
remasking may be required due to _______
noise artifacts, motion artifacts, &/or technical factors
the combo of temporal & energy subtraction techniques is called
hybrid subtraction
the T-interval delay mode is principally used in ____ imaging
cardiac
DF dose rate is lower than that for continuous analog fluoro (T/F)
true
the _____ on the retina are stimulated by ______ light
cones, bright
rods, low
fluoro was invented by
thomas edison
