B. treatment verification Flashcards
The _____is a point that the gantry, couch, and collimator rotate around
isocenter
____can be performed by using table parameters and a coordinate system
Shifts
Remember when performing shifts, they are in reference to
isocenter
____ isocenter shifts would require a positive table shift. or a addition to current table position.
Anterior, inferior, and right. ** remember AIR
The isocenter shifts ______would require a negative shift. OR a subtraction form the current table position
posterior, superior and left
if the lateral position of the couch is currently at the coordinate location of 1.5 and there is a right isocenter shift of 10.0, the new shifted couch coordinate should be
11.5cm. (10 + 1.5)
if the longitudinal position of the couch is currently at the coordinate location of 150.0 and there is a superior isocenter shift of 5.0, the new shifted couch coordinate should be
145 (150.0-5.0)
f the patient is head-first supine and the gantry is at an oblique angle of 45-degrees, the gantry angle would likely be called
LAO
if the patient is head-first prone, and the gantry angle is 90-degrees, the gantry angle may be named
right lateral
if the patient is feet-first supine, and the gantry angle is 270-degrees, the gantry angle may be named
left lateral
As the distance decreases (or gets closer to the source), the field size will measure
smaller than at isocenter
As the distance increases (or gets further from the source), the field size will measure
larger than at isocenter
______ treatment
2D
- based on conventional treatment planning
2D
- Uses a conventional simulator with x-ray equipment (fluoro simulation)
2D
- Provides a radiographic image with an outline of the tumor and a small margin
2D
- Dose distributions are limited to single fields or a few fields
2D
______ Treatments based on three-dimensional imaging to create a treatment plan
3D
- Most common imaging system is a CT simulator
3D
- Anatomy and critical structures are more accurately defined in three dimensions
3D
3D treatments use ___planning
forward
_____ is a Treatment that includes rotation of gantry with stationary MLCs (not modulated)
Non-volumetric ARC therapy
Four-dimensional treatment plan based on
4-D imaging
For _____ The radiation beam is on when the tumor is within a specific treatment position (based on a specific breathing cycle); the beam is turned off when the tumor moves out of the treatment position
4D
_____ Creates a non-uniform radiation beam in order to optimize the dose to the tumor while minimizing the dose to organs at risk near the tumor
IMRT
» MLC movement creates modulated beam
IMRT
» Highly conformal beams
IMRT
IMRT uses ___ planning
Inverse
For ______ Rotational fields are also known as arc therapy, where the radiation is delivered while the gantry is moving in an arc from one set point to another
VMAT
____ has better dose distribution than fixed-field IMRT
VMAT
_____radiosurgery is a single-fraction, high-dose radiation therapy
Stereotactic
For steroitatic radiosurgery Dosimetric accuracy required is
± 5 percent
_____ uses an onboard kV source and imager to image the patient prior to treatment when the patient is in their treatment position
kV imaging
The kV imager is a flat-panel detector located ____degrees from the kV source
180
KV images are
2D
kV images are more detailed and have better contrast than
MV images
CBCT images are
3-D or volumetric images
___ for CBCT is in shape of a cone to cover larger volumes as opposed to fan-beam CTS used in diagnostic or simulation CT scanners
Acquired beam
For CBCT, Multiple images are taken at different angles as the gantry rotates, which are then reconstructed to create a
3-D image
After reconstruction of CBCT , these images can be viewed in three planes »
Axial, sagittal, and coronal
_____ is taken in the beam’s-eye view (BEV), or from the angle and setting the
Portal imaging
_____is done before treatments start to verify the treatment plan and then at certain increments throughout treatment as specified on the prescription
Portal imaging
