A
When did installation of the first fully isocentric linear accelerator in the United States occur?
1961
Depth of maximum dose for a 6 MV beam is _____ below the skin surface.
1.5cm
Lipowitz metal is composed of which of the following?
BLT + C
Tin, Bismuth, Lead, Cadmium
Orthovoltage x-ray machines have energies in the range of which of the following?
150kv to 500kv
Depth of maximum dose for a 15 MV beam is _________ below the skin surface.
3cm
In radiation therapy, which material interacts with the radiation beam to mimic those of tissue?
Bolus
What is used in shaping the field of an electron beam treatment?
Cerrobend cutout
What is the melting point of Cerrobend?
165° F
What opposing field technique is specifically designed for treatment of the breast?
Tangential fields
When should informed consent be obtained?
Before patient receives treatment
Individual treatment doses may be defined as which of the following?
What is an anterior oblique and posterior oblique treatment field an example of?
Parallel opposed portals (POP)
A shifting field arrangement (feathering) often used in treatment of the brain and spinal cord is used primarily to
What is the series of documentation and activities performed with the purpose of optimizing patient care?
When treating with electrons, the carousel rotates to place a _________________ in the beam to spread it out.
Scattering foil
Which treatment unit has the least amount of skin sparing?
Orthovoltage
The circulator in a linear accelerator does what?
Isolates the klystron from reflected microwave power
At what rate does the cobalt 60 source decay?
1% per month
What are the two photon energies emitted by cobalt 60 are _______ MeV.
1.17MeV and 1.33MeV
What is the half-life of a cobalt 60 source?
5.26 years
What is the purpose of a bending magnet in an accelerator?
A bending magnet deflects electrons 90 to 270 degrees toward the target.
For the order x-rays travel through the linear accelerator, what comes first?
Bending magnet or target?
Bending magnet
For the order x-rays travel through the linear accelerator, what comes first?
Primary collimator or flattening filter?
Primary collimator
For the order x-rays travel through the linear accelerator, what comes first?
MLC or Ion dose chamber
Ion dose chamber
True or false?
Is the bending magnet found in the head of the accelerator?
True