Final (Quizzes) Flashcards
To include all geometric variations (ITV+SM) is ___.
Choices: • PRV • SM • CTV • GTV • IM • PTV • TV • ITV
PTV
Volume to include motion (CTV+IM) is ___:
Choices: • SM • TV • PRV • IM • ITV • IrT • OAR • IrV
ITV
Normal tissue at risk of radiation damage is called ___.
Choices: • SM • TV • PRV • IM • ITV • IrT • OAR • IrV
OAR
Tissue that receives a dose that is considered significant in relation to normal tissue tolerance:
Choices: • SM • TV • PRV • IM • ITV • IrT • OAR • IrV
IrV
As SDD increases the Penumbra ____________.
decreases
T/F: Some MLC’s create a lot of penumbra when the leaves are mounted on diverging carriages.
F
Which energy would give the most skin sparring?
6MV
18MV
20MeV
18MV
Cerrobend blocks have more field conformality than MLC’s due to the \_\_\_. FS weight material MLC leaf size
MLC leaf size
A disadvantage of a parallel opposed treatment planning technique is ___.
exit and entrance dose
An advantage of using a four field technique is:
Max dose decreases (hotspot dose decreases)
Types of beam modification:
Eliminates radiation dose to certain parts of an area where the beam is directed.
Shielding
Types of beam modification:
Allows normal dose distribution to be applied to the treated area whereas to even out the dose distribution
Compensation
Types of beam modification:
Allows for a tilt in the radiation isodose curves
Wedge filtration
Types of beam modification:
Where the distribution of the beam is altered by reducing the central exposure area to relative to the peripheral
Flattening
Which type of wedge uses the motion of the collimator jaw or leaves during treatment delivery to modify the dose distribution?
Enhanced dynamic wedge
Electron practical range related to Energy:
Energy/2 or MeV/2
Electron 80% isodose line related to Energy:
Energy/30 or MeV/30
Electron 90% isodose line related to Energy:
Energy/4 or MeV/4
Pb cutout thickness for on skin electron blocking should be at least ____________
MeV/2 in mm of Pb
Disadvantages of using MRI: (4)
lack of signal from bone
no relationship to electron density
artifacts
distortions
What are the 2 main types of image registrations?
rigid and deformable
IMRT - Delivers ___ (non uniform/uniform) fluence from different beam angles to generate a ___ (nonconformal/conformal) dose distribution
non uniform, conformal
IMRT planning assigns non uniform intensities or weights to small subdivisions of beams referred to as:
Beamlets
T/F When treating using VMAT technique radiation is delivered to the target while simultaneously moving the MLC’s and the gantry.
T
SRS treatment is usually given in __ fraction(s).
1
