Northwestern Qs Flashcards
Highest L.E.T?
Alpha
Filtration for fluoro? xx mm Al?
2.5
What phase occurs first in acute radiation syndrome?
Prodromal period
Purpose of filters in a film badge?
determine energy of exposure
Which cells are more radiosensitive? oxygenated or hypoxic?
oxygenated
An autotransformer has only one:
coil
What is the fulcrum in traditional tomography?
focal plane
what provides current to produce the electron cloud/space charge?
step-down transformer
Which phase of film processing is alkaline?
Developer
Narrow window width on digital image? =
decreased range of densities and increased contrast
What does increased size in crystals in intensifying screens do?
Increase magnification, decrease recorded detail, increase intensification factor
What bone forms medial border of obturator formaen?
Pubis
What position best demonstrates the splenic flexure ?
LAO
Where are the mandibular condyles in relation to the petrous pyramids for properly positioned SMV?
anterior
photostimulable imaging plate loses what % of energy in 8 hrs?
25%
in an image intensifier, which phosphor is larger?
input > output
effective dose for knee XR?
.005 mSv
The concept of a sensitive key molecule is the basis for which theory?
Target theory
Which structure of the eye is the most radiosensitive?
Lens
What kind of mAs/Kvp combo would result in least pt dose and lowest heat delievered to anode?
Low mAs and high kVp
What kind of e-wave has the highest frequency?
Gamma
Sour-to-skin distance minimum for stationary fluoro?
15 in
Symptoms of hematologic syndrome?
Vomiting + diarrhea, malaise + lethargy
What does the autotransformer do?
increase kVp
`Tungsten is an ideal anode material for which 3 reasons?
- high melting point 2. high atomic number 3. abiliity to conduct heat
What happens if blue/green screens/films are mismatched?
resulting film is too light
Which component is uniquely essential to digital fluoro?
ADC
Increasing thickness of phoshpor layer in screens results in ?
- increased intensification factor 2. decreased detail
What does the phosphor in PSP do during XR exposure?
traps electrons
Right colic flexure best demonstrated in which position?
RAO
What position is hand in for supine lateral projection of humerus?
posterior aspect against pt side
Most accurate pulse measurement?
Apical
when does leakage radiation occur?
when an exposure is made
what kind of radiation gives pt highest dose?
alpha
what dose will cause temporary sterility in females?
200 rads
what is the minimum source to table top distance for mobile fluoro units?
12 in
what kind of generator would give 120 electric pulsese to an XR tube per second?
single-phase full wave rectification
what current is required to heat the filament in an XR tube?
3-4 amps
what indicator do cassetteless systems use as an indicator of exposure?
DAP
What is pixel pitch?
the space between pixels
Histogram analysis does NOT
manipulate image contrast
what kind of joint is synarthrodial?
costochondral joints
what is a common complication of central venous line placement?
pneumothorax
30 keV XR photon ejects k-shell e w/ binding energy of 3 kEv - resultant energy of photoelectron?
27 kEv
amount of leakage radiation from tub should not exceed?
100 mR/hr at 1 meter
blend of CT/nuc med - uses positron-emitting radionuclide?
PET
LD 50/60 for humans w/ min clinical support?
320-540 Rads
irradiation of human cells produces:
unstable molecules, free radicals, toxic substances
how many coulombs/kg in the Roentgen?
2.58 x 10^-4 C/kg
stochastic radiation response?
all or nothing
what contributes most to general population exposure each year?
radon gas
how does the IR move during conventional linear tomography?
opposite the tube
longer scale of contrast, ____ exposure latitude?
increased
LUT in digital imaging, purpose?
reference to eval raw image formation, correct luminance values, give image appropriate brightness/contrast
mitral stenosis?
narrowing of bicuspid valve (atrium to ventricle)
thoracic duct function?
lymph to L subclavian vein
what drug to give in case of severe anaphylactic shock after contrast administration?
adrenaline
early symptoms anaphylactic shock?
itching, sneezing, nausea
majority of DNA damage results from ____ ____ of radiation
indirect effect
BEIR VII report in 2005 supports previous _____ _____ risk model
linear nonthreshold
occupational radiation monitoring is required when it is likely an individual will receive ___ _____ in any single year
0.5 rem
according to NRCP report 93, ____ _____ are the largest artificial source contribution to average annual effect dose equiv in US
diagnostic XR
metal filters used in film badges are used to…?
determine radiation energy/exposure
radiation-induced cataracts are considered to be _______, ______ effects
non-linear, threshold
output current from the secondary of the transformer is ______ _____
alternating current
most constant voltage to XR tube provided by..??
3 phase, 12 pulse
magnification mode for multifocus II is used…
spatial resolution is improved
sampling frequency and pixel pitch are used to determine:
spatial resolution
what digital imaging system converts XR to light prior to producing the image?
indirect flat panel (not CR
what test is not used to determine TB infection status?
VRSA
what uses zinc cadmium sulfide in the phosphor layer?
II output screen
where is the mitral valve?
between the L atrium and L ventricle
a higher kVp results in a _____ latitude
narrower
