Radiation Therapy Techniques Exam
Questions with Correct Answers
Mark all concerning wedges:
- reduce hot spots
- can be hard or dynamic
- used for tissue compensating of sloping surfaces
- known as superflab - Answer-- reduce hot spots
- can be hard or dynamic
- used for tissue compensating of sloping surfaces
Irradiated volume - Answer-Volume of tissue receiving a significant dose (50% or more
of the prescribed dose)
GTV - Answer-The gross, palpable, visible, or clinically demonstratable location of the
cancerous growth
CTV - Answer-Tissue volume that contains the clinical and subclinical disease
PTV - Answer-Surrounds the clinical and subclinical growth and an additional margin to
compensate for different types and variations and uncertainties of the beam
Treated volume - Answer-Larger than the target volume, encompasses the additional
margins around the target to allow for limitations of the treatment technique
Localization - Answer-geometrical definition of the tumor and anatomic structures using
surface or fiducial marks for reference
Verification - Answer-a check that each beam/port covers the intended treatment area
and spares organs at risk
Simulation - Answer-The process carried out by the radiation therapist under the
direction of the radiation oncologist. This is a mock up of the patient positioning for
treatment
IFD - Answer-Patient separation between two beams
Is a photon beam heterogenous or homogenous? - Answer-Heterogenous
What is the average energy of an 18MV beam? - Answer-6mv
SAD setup - Answer-iso in 100 or less
SSD setup - Answer-iso is 100 or more
, What is the importance of shielding blocking devices - Answer-- high intensity
- high atomic number
- low melting point
Shielding material should the original intensity of the beam to ___% or less - Answer-5
MLC or blocks should be at least ___ cm away to avoid ___scatter - Answer-15-20,
electron
What are the material and amount of those materials in cerrobend? - Answer-Bismuth -
50%
Lead - 26.7%
Tin - 13.3%
Cadmium - 10%
What is the most toxic ingredient in cerrobend? - Answer-Cadmium
What is true about compensators? - Answer-- maintain skin sparing
- used for tissues with different densities
- allow for normal depth dose for irregular surfaces
What are the different types fo wedge filters? - Answer-- EDW
- Virtual
- Dynamic
- Individualized
What does bolus change? - Answer-The location of DMAX
What does bolus do to skin sparing? - Answer-Decreases skin sparing because DMAX
depth is decreased.
What angle are EDW wedge filters measured at? - Answer-10cm
Do compensators affect DMAX? - Answer-no
4mv DMAX - Answer-1cm
6mv DMAX - Answer-1.5 cm
10mv DMAX - Answer-2.5cm
18mv DMAX - Answer-3.5cm
24mv DMAX - Answer-4cm
Questions with Correct Answers
Mark all concerning wedges:
- reduce hot spots
- can be hard or dynamic
- used for tissue compensating of sloping surfaces
- known as superflab - Answer-- reduce hot spots
- can be hard or dynamic
- used for tissue compensating of sloping surfaces
Irradiated volume - Answer-Volume of tissue receiving a significant dose (50% or more
of the prescribed dose)
GTV - Answer-The gross, palpable, visible, or clinically demonstratable location of the
cancerous growth
CTV - Answer-Tissue volume that contains the clinical and subclinical disease
PTV - Answer-Surrounds the clinical and subclinical growth and an additional margin to
compensate for different types and variations and uncertainties of the beam
Treated volume - Answer-Larger than the target volume, encompasses the additional
margins around the target to allow for limitations of the treatment technique
Localization - Answer-geometrical definition of the tumor and anatomic structures using
surface or fiducial marks for reference
Verification - Answer-a check that each beam/port covers the intended treatment area
and spares organs at risk
Simulation - Answer-The process carried out by the radiation therapist under the
direction of the radiation oncologist. This is a mock up of the patient positioning for
treatment
IFD - Answer-Patient separation between two beams
Is a photon beam heterogenous or homogenous? - Answer-Heterogenous
What is the average energy of an 18MV beam? - Answer-6mv
SAD setup - Answer-iso in 100 or less
SSD setup - Answer-iso is 100 or more
, What is the importance of shielding blocking devices - Answer-- high intensity
- high atomic number
- low melting point
Shielding material should the original intensity of the beam to ___% or less - Answer-5
MLC or blocks should be at least ___ cm away to avoid ___scatter - Answer-15-20,
electron
What are the material and amount of those materials in cerrobend? - Answer-Bismuth -
50%
Lead - 26.7%
Tin - 13.3%
Cadmium - 10%
What is the most toxic ingredient in cerrobend? - Answer-Cadmium
What is true about compensators? - Answer-- maintain skin sparing
- used for tissues with different densities
- allow for normal depth dose for irregular surfaces
What are the different types fo wedge filters? - Answer-- EDW
- Virtual
- Dynamic
- Individualized
What does bolus change? - Answer-The location of DMAX
What does bolus do to skin sparing? - Answer-Decreases skin sparing because DMAX
depth is decreased.
What angle are EDW wedge filters measured at? - Answer-10cm
Do compensators affect DMAX? - Answer-no
4mv DMAX - Answer-1cm
6mv DMAX - Answer-1.5 cm
10mv DMAX - Answer-2.5cm
18mv DMAX - Answer-3.5cm
24mv DMAX - Answer-4cm
