RSAP 180 Learning Outcome #9 Review

What are some common locations in which mobile radiography is performed?

• Emergency departments (ER)

• Intensive care units (ICU)

• Patient rooms

• All of the above

TRUE or FALSE: Most modern mobile machines are of the capacitor discharge type

• True

• False

Answer explanation

Battery operated mobile machines are the most commonly used modern mobile machine

In a capacitor discharge unit, a residual charge can give rise to a ___________ and results in x-ray emission even though the irradiation switch is not activated

• Light current

• Dark current

• Dark force

• Continuing current

Answer explanation

In a capacitor discharge unit, after an x-ray irradiation has been made, there is a residual charge left in the capacitors. The residual charge can give rise to a “dark current” and result in x-ray emission even though the irradiation switch is not activated. Therefore, the residual charge must be fully discharged before the unit is left unattended.

What grid ratio is commonly used for mobile radiography?

• 16:1

• 12:1

• 8:1

• Grids cannot be used in mobile radiography

Answer explanation

8:1 grid provides a wider positioning latitude. Lower grid ratios allow for more positioning latitude and decreased grid errors

As per SC35, what is the minimal distance a radiographer should stand from the primary x-ray beam?

• 1 meter

• 2 meters

• 6 meters

• 3 meters

TRUE OR FALSE: A battery operated mobile unit uses a capacitor that stores electrical charge.

• True

• False

Answer explanation

A battery powered mobile unit uses 2 sets of batteries; one set controls the x-ray power output, the second set provides the power for the self-propelled driving ability.

All of the following are advantages of a battery powered portable x-ray units EXCEPT:

• Have better mobility, recharge capabilities, consistent exposure, and higher KVP output

• Lightweight, small and easy to maneuver.

• Many exposures possible before recharge

• Provides wide ranges of satisfactory kVp & mAs

Answer explanation

Lightweight, small and easy to maneuver applies to the capacitor discharge units. Battery operated ones are a lot larger and heavier.

The batteries in battery-operated mobile x-ray units provide power to:

• X-ray tube

• Machine travel

• Braking mechanism

• All of the above

The following are all important technical matters that must be clearly understood to perform optimal mobile radiography EXCEPT:

• Use of a grid

• Filtration

• Anode heel effect

• Source to image distance (SID)

What considerations should be employed when using a grid in mobile radiography?

• Ensure the grid is level

• Ensure the grid and x-ray beam are properly centered

• Ensure the correct focal distance is being used

• All of the above