Stack #735079 Word Scramble

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Question	Answer
mAs literally determins what	the number of electrons boiled off of the filament
what imaging system has a linear exposure relationship?	digital
over exposed or underexposed between the two which one would be least likely to be repeated?	overexposed
___ represents the different absorbtion characteristics of the body	density
with film/screen systems image density is represented by twhat?	Black metallic silver deposit patterns
What happens to density as processing developer temp. increases?	it increases
what happens to density if collimation is increased? (field size is made smaller?)	it decreases
the intensity of a beam is less on which end of the tube?	Anode
all other factors remaining constant, if the intinsifying screen is switched to a faster one, what effect will it have on density?	it increases
As kVp increases and everything else remains constant what happens to density	it increases
what is the absorbing material in a grid?	lead
according to the inverse square law if the sistance is reduced to 1/2 the intensity will?	increase by a factor of 4
total filtration in the x-ray tube head assembly affects density by___	removing low energy photons
what happens to density with increase in tissue thickness?	it will decrease
which set will produce the highest contrast? 50@20, 58@10, 67@5, 77@2.5	50@20
the lower the kVp the _____ resultant of contrast	higher
what tissue group will likely have the greatest xray absorption?	bone
which difference in densities will have the lowest contrast? 1.8, 1.5, 1.0, 0.5	0.5 because the lowest difference between densities will present low contrast
where does black metallic silver formation begin?	sensitivity speck
what layer in general film is not duplicated?	the base
which layer is manufactures to reduce eye strain?	the base
a grid will _____ scatter production... how/why?	decrease, it only reduces the amount of scatter that reaches the receptor...
an increase in developer time will ____ contrast	decrease
a compensating filter will ________ contrast	decrease
scatter _____ contrast	decreases
collimation ____ contrast	increases
the level or degree of penetration of the xray beam is a primary factor in determining _______	the scale of contrast
the higher the kvp and mAs the ________ density	greater the
the lower the kVp the ____ the contrast	higher
scatter, patient dose, density... which one does kVp affect?	all of them
primary controller of density	mAs
___ literally controls the current through the xray tube	mAs
what determins the energy of the x-ray beam?	kVp
20 mAs is used at 40'' SID what will the mAs be at 72 '' SID	65 mAs
24 mAs is used for a slow speed screen... what would the mAs be for a fast moving screen?	6 new mAs=24*(1/4)
if the collimation field is made smaller what will happen to the density if the mAs is not adjusted?	it will decrease
purpose of a grid?	absorb scatter
20 mAs is used for a non grid tech. what mAs should be used for an 8:1 grid?	80
increasing the screen speed allows for a reduction in ____ needed	mAs
if changed from a 11x14 cassette to a 10x12 cassette what adjustment needs to be made and why?	increase mAs because the photons that would have exposed the patient or the image receptor are removed.
to obtain a higher scale of contrast you must _____ kVp and ____mAs	decrease;increase
for every 4-cm change in tissue thickness mAs must be changed by ____	a factor of 2
____ controls the overall blackness of a radiograph?	mAs
the ____ the SID and the ____ the OID the sharper the image	longer;shorter
films with thicker emulsions or larger silver halide crystals will have ______ sharpness	less
in digital, changing a negative image to a positive image is called what?	image inversion
adjusting the brightness and contrast is called what?	window and leveling
in a psp plate the trapping of electrons in the conduction band creates what?	latent image
which kVp is capeable of producing the lowest contrast? 50,60,70,80	80, the higher th kVp the more penetration resulting in a low contrast image
which kVp setting will provide the most kenetic energy to filament electrons?	100 the higher the kVp the more energy
which xray energy would have the lightest shades ? 20 50 80 or 100	20 less energy more chance of the photons being absorbed in the body less hitting the IR
which tissue group has the lowest water content?	fat
which tissue group has the highest water content?	muscle
what is the primary absorber of xrays in bone?	calcium
in which layer of the intensifying screen is xray energy converted into light?	active layer
which layer of film contains halide crystals?	emu;sion
once the halide crystals are exposed the sensitivity speck will first aquire what charge?	negative
why is scatter exposure undesirable?	it decreases contrast
compensating filters in effect _____ tissue thickness and density	increase
which OID would result in the greatest increase in radiographic contrast? 1,4,6,12	12
positive contrast media will ____ contrast	increase
what increases the voltage to kilovoltage in the xray circuit?	step up transformer
if the lead strips are 4.0 mm high and are separatedby an interspace of 025mm what is the grid ratio?	4.0/.25 = 16:1
if lead strips are 2.0mm high and are separated by an interspace of.25mm what is the grid ratio?	2.0/.25=8:1
s radiograph is produced using 85@8 without a grid. a second film is requested using an 8:1 grid with a conversion factor of 4 what mAs is needed?	8 * 1/4 = 32/1 = 32 mAs (cross multiply
1st radiograph is 85@10 without a grid what would be the mAs if using a 16:1 grid?(conversion factor of 6)	10* 1/6 = 60/1 = 60 mAs
1st image used 85@30 with a 12:1 grid 9conversion factor 5) 2nd film will be same tech. with a 16:1 grid (conversion of 6) what mAs is needed	30* 5/6= 180/5 = 36 mAs
what are the grid-conversion factors for no grid, 5:1, 8:1, 12:1, and 16:1 grids?	1,3,4,5,6
when the patient thickness is more that 10cm the kVp should be	greater than 60
transmission is responsible for what?	the dark areas on the image
absorption is responsible for	the light areas
the higher the frequency of a grid the ____ the interspace must be... & the ___the grid ratio	thinner;higher
contrast is _____ when a grid is used	doubled
what will go down, what must be increased, when a grid is placed in beam?	density will go down, exposure factors must be increased to compensate
parallel linear grid	all lead sstrips are parallel to eachother, they absorb a large amount of the primary beam resulting in some cut-off
with a decrease in SID grid cut-off will	increase
criss-cross ot cross hatched or cross grid	horizontal lead strips, vertical lead strips, primary beam must be centered perp. to grid, grid must remain flat
focused grid	fabricated so the strips are parallel to the primary xray path across the entire image receptor. minimizes grid cut-off
focused linear grids	lead strips are angled to match divergence of beam, primary beam will align with interspace material, scatter absorbed by lead strips
focused linear grids	convergence line, narrow positioning latitude, improper centering results in periphereal cut-off, only useful at present SID distance
which grids require careful alignment with tube?	higher frequency grids
what are the four main grid errors?	off-level, off-center, off focus, upside down
the central axis is not perpendicular to the grid, and if partial cut off occurs over the entire image receptor and comes out underexposed what type of error is this?	off level
when a focused grid has partial grid cut-off over t he entire image nad it looks underexposed what type of error is it?	off center
if a grid is not positioned at the specified focal distance, grid cut-off occurs and the optimal density decreases with distance from the central ray... cut off is toward the edge of image... what error?	off focus
if complete grid cutoff occurs except in the central region of the central ray what error is it?	upside down grid
which grid is better, focused or parallel?	focused
what are the three factors to consider with grid selection?	kVp, degree of clean-up, patient dose

Created by: b.xray