Ch. 13 Minimizing Patient Dose (Exp II) Flashcards
The conscientious radiographer can reduce the patient dose by at least ____ in most examinations by choosing appropriate exposure factors.
50%
The maximum exposure received by the patient is at:
The skin entrance to the body
Which of the following radiographic procedure delivers the lowest entrance skin exposure?
a. Hip
b. Pelvis
c. Lumbar spine
d. Elbow
d. Elbow
The Food and Drug Administration (FDA) sets an entrance skin exposure limit of ____ R.min for fluoroscopic systems in the US.
11.5 R/min
The radiation intensity from a diagnostic x-ray unit will vary in:
______ relationship with mAs
______ relationship with the square of the kVp
______ relationship with the square of the distance
- Direct relationship with mAs
- Direct relationship with the square of the kVp
- Inverse relationship with the square of the distance
To reduce patient exposure, the _____ consistent with image quality should be selected.
Highest kVp
Which x-ray generator will substantially decrease the patient entrance skin exposure?
Three-phase, 12 pulse
Patient entrance skin exposure decreases as:
SID increases
When the primary-beam field size ___, the patient exposure ____.
Decreases; decreases
Each of the following is a type of gonad shield EXCEPT:
a. Flat contact
b. Shadow
c. Collimator
d. Shaped contact
c. Collimator
The use of a grid will:
Increase patient exposure
An effective method of reducing patient exposure is to use:
The highest speed possible image receptor
Entrance skin exposure is _____ exposure.
Maximum
Skull radiography routinely includes a posterior-anterior (PA) projection. This is intended to:
Reduce dose to the lens of the eye
The approximate entrance skin exposure (ESE) for a radiographic study taken at 90 kVp and 23 mAs is:
103.5 mR
When SID or SOD increases:
Patient ESE decreases
When comparing ESE and actual dose to an area of interest:
Actual dose is lower than ESE
In an effort to reduce dose, the recommended SID for routine radiography is:
44-48 inches
In an effort to minimize patient dose:
a. The small focal spot should be used
b. The large focal spot should be used
c. Beam filtration should be minimum
d. None of the above
d. None of the above
Of the choices below, the combination of exposure factors that would minimize patient dose would be:
a. 24 mAs, 80 kVp, 8x10” field size, 44” SID
b. 12 mAs, 92 kVp, 8x10” field size, 40” SID
c. 6 mAs, 106 kVp, 8x10” field size, 44” SID
d. 24 mAs, 80 kVp, 10x12” field size, 40” SID
c. 6 mAs, 80 kVp, 8x10” field size, 44” SID
