A particular radiograph was produced using 6 mAs and 110 kVp with an 8:1 ratio grid.
The radiograph is to be repeated using a 16:1 ratio grid. What should be the new mAs?
(A) 3 mAs
(B) 6 mAs
(C) 9 mAs
(D) 12 mAs
(Saia, p 328)
Give this one a try later!
9 mAs
--To adjust exposure factors, you simply compare the old with the new:
6 (old mAs) 4 (old grid factor)
___________=______________
x (new mAs) 6 (new grid factor)
4x = 36; x = 9 mAs using 16:1 grid
,In a PA projection of the chest being used for cardiac evaluation, the heart measures
15.2 cm between its widest points. If the magnification factor is known to be 1.3, what
is the actual diameter of the heart?
(A) 9.7 cm
(B) 11.7 cm
(C) 19.7 cm
(D) 20.3 cm
(Fauber, pp 90-92)
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11.7 cm
The formula for magnification factor is MF = image size ÷ object size. In the
stated problem, the anatomic measurement is 15.2 cm, and the
magnification factor is known to be 1.3. Substituting the known factors in the
appropriate equation,
MF = image size ÷ object size ; 1.3 = x ÷ 15.2;
x = 15.2 ÷ 1.3 = 11.69 cm (actual anatomic size)
Which of the following will contribute to the production of longer-scale radiographic
contrast?
1. An increase in kVp
2. An increase in grid ratio
3. An increase in photon energy
(A) 1 only
(B) 1 and 2 only
(C) 1 and 3 only
(D) 1, 2, and 3
Give this one a try later!
An Increase in kVp
, An Increase In Photo Energy
An exposure was made using 300 mA, 0.04 s exposure, and 85 kVp. Each of the
following changes will decrease the radiographic density by one-half except change
to
(A) 1/50 s exposure.
(B) 72 kVp.
(C) 10 mAs.
(D) 150 mA.
(Selman, pp 213-214)
Give this one a try later!
10 mAs.
[Radiographic density is directly proportional to mAs. If exposure time is
halved from 0.04 (1/25) s to 0.02 (1/50) s, radiographic density will be cut in
half. Changing to 150 mA will also halve the mAs, effectively halving the
radiographic density. If the kVp is decreased by 15 percent, from 85 to 72
kVp, radiographic density will be halved according to the 15 percent rule. In
order to cut the density in half, the mAs must be reduced to 6 (rather than
10)]
The use of which of the following is (are) essential in magnification radiography?
1. High-ratio grid
2. Fractional focal spot
3. Direct-exposure film
(A) 1 only
(B) 2 only
(C) 1 and 3 only
(D) 1, 2, and 3
Give this one a try later!
, Fractional Focal Spot
The purpose of the automatic processor's circulation system is to
(A) monitor and adjust temperature.
(B) agitate, mix, and filter solutions.
(C) move the film and change its direction.
(D) monitor the solution and replace it as necessary.
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Agitate, Mix, and Filter Solutions.
Which of the following factors influence(s) the production of scattered radiation?
1. Kilovoltage level
2. Tissue density
3. Size of field
(A) 1 only
(B) 1 and 2 only
(C) 1 and 3 only
(D) 1, 2, and 3
Give this one a try later!
Kilovoltage Level
Tissue Density
Size of Field
The radiograph is to be repeated using a 16:1 ratio grid. What should be the new mAs?
(A) 3 mAs
(B) 6 mAs
(C) 9 mAs
(D) 12 mAs
(Saia, p 328)
Give this one a try later!
9 mAs
--To adjust exposure factors, you simply compare the old with the new:
6 (old mAs) 4 (old grid factor)
___________=______________
x (new mAs) 6 (new grid factor)
4x = 36; x = 9 mAs using 16:1 grid
,In a PA projection of the chest being used for cardiac evaluation, the heart measures
15.2 cm between its widest points. If the magnification factor is known to be 1.3, what
is the actual diameter of the heart?
(A) 9.7 cm
(B) 11.7 cm
(C) 19.7 cm
(D) 20.3 cm
(Fauber, pp 90-92)
Give this one a try later!
11.7 cm
The formula for magnification factor is MF = image size ÷ object size. In the
stated problem, the anatomic measurement is 15.2 cm, and the
magnification factor is known to be 1.3. Substituting the known factors in the
appropriate equation,
MF = image size ÷ object size ; 1.3 = x ÷ 15.2;
x = 15.2 ÷ 1.3 = 11.69 cm (actual anatomic size)
Which of the following will contribute to the production of longer-scale radiographic
contrast?
1. An increase in kVp
2. An increase in grid ratio
3. An increase in photon energy
(A) 1 only
(B) 1 and 2 only
(C) 1 and 3 only
(D) 1, 2, and 3
Give this one a try later!
An Increase in kVp
, An Increase In Photo Energy
An exposure was made using 300 mA, 0.04 s exposure, and 85 kVp. Each of the
following changes will decrease the radiographic density by one-half except change
to
(A) 1/50 s exposure.
(B) 72 kVp.
(C) 10 mAs.
(D) 150 mA.
(Selman, pp 213-214)
Give this one a try later!
10 mAs.
[Radiographic density is directly proportional to mAs. If exposure time is
halved from 0.04 (1/25) s to 0.02 (1/50) s, radiographic density will be cut in
half. Changing to 150 mA will also halve the mAs, effectively halving the
radiographic density. If the kVp is decreased by 15 percent, from 85 to 72
kVp, radiographic density will be halved according to the 15 percent rule. In
order to cut the density in half, the mAs must be reduced to 6 (rather than
10)]
The use of which of the following is (are) essential in magnification radiography?
1. High-ratio grid
2. Fractional focal spot
3. Direct-exposure film
(A) 1 only
(B) 2 only
(C) 1 and 3 only
(D) 1, 2, and 3
Give this one a try later!
, Fractional Focal Spot
The purpose of the automatic processor's circulation system is to
(A) monitor and adjust temperature.
(B) agitate, mix, and filter solutions.
(C) move the film and change its direction.
(D) monitor the solution and replace it as necessary.
Give this one a try later!
Agitate, Mix, and Filter Solutions.
Which of the following factors influence(s) the production of scattered radiation?
1. Kilovoltage level
2. Tissue density
3. Size of field
(A) 1 only
(B) 1 and 2 only
(C) 1 and 3 only
(D) 1, 2, and 3
Give this one a try later!
Kilovoltage Level
Tissue Density
Size of Field
