Week #7 Review Flashcards
(48 cards)
An xray tube and image intensifier attached in a C configuration
C-arm/base
Offers both static and dynamic imaging during the procedure
Display monitors
What power source do mobile xray units most commonly have?
Capacitor discharge generators or battery powered
-Operates by charging a series of silicon-controlled rectifiers from the DC voltage of a nickel-cadmium battery or a wall
-by electrically stacking the SCRs the charge is stored at a very high voltage
-during exposure the charge is released
Capacitor Discharge models
What is a disadvantage to the capacitor discharge models?
The capacitor may continue to discharge after the usable exposure, which can create radiation leakage
Generators in these units produce output that is essentially high frequency
Battery powered cordless models
-Powered by 10 to 16 rechargeable, sealed, lead acid type 12-volt batteries connected in series
-equipped with circuitry to monitor battery strength
Battery powered cordless models
According to SC35, how far from the mobile xray unit must the tech be if not wearing ppe?
3 metres
-consists of two perpendicular sets of ceiling mounted rails
-attached to the xray tube by a telescoping column
-detents
Ceiling support system
-has a single column with rollers at each end
-the xray tube slides up and down the column as the column rotates
Floor to ceiling support system
-has a single column positioned on one or two floor mounted rails
Floor support system
-one end of the c arm is connected to an xray tube
-the other end is connected to the image receptor
-may be ceiling or floor mounted
C-arm support system
What is the radiation limit for a controlled area?
20 mSv per year
What is the radiation limit for an uncontrolled area?
1 mSv per year
The immediate area where xray equipment is used such as the procedure room and xray control booths
Controlled area
Areas occupied by individuals such as patients, visitors to the facility, and employees who do not work routinely with or around radiation sources
Uncontrolled area
What is the radiation limit in a controlled area with a radiation sensitive population?
0.30mSv per year
What is the standard for control booth shielding?
No operator is occupationally exposed to more than 0.4mSv/week
Provides shielding from the direct xray beam and therefore must be placed in such an orientation as to intersect the xray beam
Ex. Wall behind vertical IR
Primary protective barrier
Provide shielding from scattered and leaked X-rays
Ex. Ceiling
Secondary protective barriers
The xray tube should never be directed towards the control booth
(These walls are considered secondary barriers)
True
A measure of the operational time or the amount of use of the xray equipment over a set period of time
Maximum workload (W)
The fraction of time that the area under consideration is occupied by the individual who spends the most time at that location while the xray equipment is operating
Occupancy factor (T)
Admin offices, attended waiting rooms, adjacent xray rooms, image viewing areas, xray control rooms…
T=1
