Rad Physics Sample Questions Flashcards
anatomy can affect film density through its variations of..
pathologies, tissue thickness, tissue age
a satisfactory lateral lumbar spine radiograph is performed using 40 mAs at 84 kVp and a 14x17’ field size. If a spot view of L1 is performed using a 5x5 field size and the tequnique is not changed, how will this affect the radiograph?
decrease density
the overal darkness of a radiograph is known as
density
a technique of 400 mA and .05 sec and 75 kVp has been used to produce a radiograph. A second radiograph is taken, this time using 200 mA. How will this affect the radiographic density?
decrease enough to repeat the radiograph
What effect does developer temperature have on the density of a radiograph?
developer that is too hot will increase the density of the film
What can be expected if a radiograph normally taken at 72”, is inadvertently taken at 40”?
image underexposed
Given an original technique of 30 mAs and 80kVp, which of the following will produce a radiograph with double the density?
60 mAs and 80kVp
In the diagnostic xray range, the smallest change in mAs that can be perceived on a radiograph is?
30%
A device that is commonly used to even out radiographic density, due to different patient part thickness is a
compensating filter
compared with 200 speed cassettes, 400 speed screen cassettes
require less xrays to get the phosphors to emit enough light to transfer the information
A lateral cervical was taken at 40” using 7.5mAs at 75 kVp the density was optimal. The tech remembered lateral cervical films are to be taken at 72”, what will the new technique be?
22.5mAs at 75 kVp
An increase in SID/FFD with no change in technique will result in a radiograph with
decreased density; decreased detail
the routine care of radiographic intensifying screens requires that they be:
periodically cleared with a specific screen cleanser
an increase in OID/OFD will ___film density.
decrease
compared with 400 speed screen cassettes, 200 speed screen cassettes
require more xrays to get the phosphors to emit enough light to transfer the information
short exposure times are recommended for improving
motion
which of the following would be used to reduce magnification?
shortest possible OID
smallest focal spot size
select the technique taht would produce a film with the highest contrast on an AP lumbopelvic projection? 300mA, .1sec, 80kVp 300 mA, .1 sec, 110 kVp 300mA, .1 sec, 75kVp 300 mA, .1 sec, 60 kVp
300 mA, .1 sec, 60 kVp
15mAs at 65 kVp
the above technique produces an optimal quality radiograph on a 200 speed screen cassette. if a 400 speed screen cassette is used and the technique is not changed. How will this afect the radiographic density?
there will be a significant increase in density, enough to alter the technique
what do you do to reduce radiographic unsharpness?
decrease screen speed
decrease focal spot size
decrease OID
as mAs is decreased from 50 to 25
radiographic density decreases
select the answer that arranges patient densities in order from most radiolucent to most radiopaque
gas, muscle, bone, metal
select the technique that would produce a radiograph with the most density 300mA, .1 sec and 90 kVp 300mA, .1 sec, 60kVp 300mA, .1 sec, 110kVp 300 mA, .1 sec, 75 kVp
300 mA, .1 sec, 110kVp
the 15% rule states that
density may be halved by decreasing kVp by 15%
magnification is caused by
an incrased OFD
which of the following may be used to control motion duringa radiographic exam?
immobilization devices (non threatening) precise instructions shortest possible exposure time
a technique of 400mA and .05 sec and 75 kVp has been used to produce a radiograph. A second radiograph is taken, this time as 200mA. How will this affect the radiographic detail?
decrease enough to repeat the radiograph
an increased SID/FFD with no change in technique will result in a radiograph with?
decreased density, decreased detail
an increase in OID/OFD will___film detail
decrease
short exposure times are recommended for improving?
motion
which of the following would be used to reduce magnification?
shortest possible OID
longest FFD/SID
select the technique that would rpoduce a film with the highest contract on AP lumbopelvic projection 300mA, .1sec, 80kVp 300mA, .1sec, 110 kVp 300mA, .1 sec, 75kVp 300mA, .1 sec, 60 kVp
300mA, .1 sec, 60 kVp
which of the following can be used to reduce radiographic unsharpness?
decrease screen speed
decrease focal spot size
decrease OID
the 15% rule states that
density may be halved by decreased kVp by 15%
magnification is caused by
an increased OFD
which of the following may be used to control motion during a radiographic examination?
immobilization devices (non threatening) precise instructions shortest possible exposure time
list 3 that can clean up scatter
recumben radiographs, grid compression bands, low kVp
an APLP radiograph was taken table top using 25mAs @ 75kVp. The tech remembered after taking the film that APLPs are taken using the bucky. How will the radiographic detail be affectd if same technique is used?
will decrease detail
a grid must be used when the part measures more than___cm
10-11cm
