MEDICAL DOSIMETRIST CERTIFICATION BOARD PRACTICE TEST
DVH
Graph showing volume receiving dose within a specified range.
QUANTEC
Organization setting dose tolerances for treatment plans.
Clinical electron beams
Electrons lose energy at a rate of 2 MeV per cm in soft tissue.
Dose uniformity factors
Beam energy, tissue inhomogeneity, and patient thickness.
Dose calculation uncertainty
Best accounted for by Monte Carlo method.
IMRT technique
Patient treated slice by slice with intensity-modulated beams.
Thermal neutron absorber
Boronated polyethylene.
Relative skin dose increase
Increased by increasing bolus material thickness.
Symptomatic radiation pneumonitis
Risk increased by certain chemotherapy agents.
Arrow #2
Points to pancreas.
V20 of total lung
Cannot be determined from the graph.
DVHs confirmation
Confirms normal tissue tolerances are respected.
Sliding window vs. step-and-shoot
Sliding window likely has higher total monitor units.
Photon field abuts electron field
Results in photon side hot spot, electron side cold spot.
Arrow #1
Points to maxillary sinus.
Isocentric, parallel opposed oblique fields
May result in decreasing max dose as isocenter dose increases.
Increased skin dose in IMRT
Caused by use of high-energy photons.
Incorrectly labeled organ
Stomach in the CT scan.
increased skin dose in IMRT for prostate cancer
Factors include prone position, wedge under knees, use of high-energy photons, and
carbon fiber couch.
organ INCORRECTLY labeled in CT scan
Options are liver, stomach, left kidney, and aorta.
radiation beam delivery in step-and-shoot IMRT
The correct process involves MLC movement direction and beam delivery.
correct diagram for 90% and 105% distribution
, Options include diagrams labeled #1, #2, #3, and #5.
Arrow #2 points to
Options are descending thoracic aorta, carina, pulmonary trunk, and left pulmonary
artery.
Characteristics of MLC in current medical LINACs
Options include field sizes, isodose curves, field shapes, and leaf shape verification.
V20 from a DVH for both lungs
It represents the dose or volume relationship for lung exposure.
eliminating divergence into the lung for breast treatment
Options involve adjusting angles, matching beam edges, and central axis alignment.
physical penumbra width definition
It is the lateral distance between specific isodose curves at dmax level.
techniques to avoid cold spots in post-mastectomy chestwall treatment
Options include field matching, overlap, junction movement, and field gap at the skin
surface.
minimum nominal distance for tissue compensator placement
Options are 5.0 cm, 10.0 cm, 20.0 cm, and 25.0 cm.
X-ray contamination dose range when treating with electrons
Approximately ranges from 0.1% to 12%.
purpose of rounded ends on multi-leaf collimator leaves
They are used for specific functions related to field shaping and penumbra.
geometric penumbra statement
Options involve penumbra size, block-to-skin distance, source distance, and collimator
setting.
characteristics of a 12 MeV electron beam
Describes the depth characteristics and practical range of the beam.
calculation method for primary and scattered dose components
Options include Convolution superposition, Ray tracing, Manchester, and Monte Carlo.
effective field size calculation for a 10x10 field with 30% blocked
Determining the area for a specific field size and block percentage.
concept of equivalent squares in dose calculation
Understanding the concept and application of equivalent squares in dose calculations.
Ray tracing
A rendering technique for generating an image by tracing the path of light as pixels in an
image plane.
C. Manchester
A type of ionization chamber used for radiation dosimetry.
Monte Carlo
A computational algorithm used in radiation therapy for dose calculation and simulation.
Effective field size
The area of the radiation field that contributes to the dose delivery, accounting for
blocked areas.
Equivalent squares
Concept used in dose calculation where different field shapes have the same dosimetric
properties.
Monitor units
DVH
Graph showing volume receiving dose within a specified range.
QUANTEC
Organization setting dose tolerances for treatment plans.
Clinical electron beams
Electrons lose energy at a rate of 2 MeV per cm in soft tissue.
Dose uniformity factors
Beam energy, tissue inhomogeneity, and patient thickness.
Dose calculation uncertainty
Best accounted for by Monte Carlo method.
IMRT technique
Patient treated slice by slice with intensity-modulated beams.
Thermal neutron absorber
Boronated polyethylene.
Relative skin dose increase
Increased by increasing bolus material thickness.
Symptomatic radiation pneumonitis
Risk increased by certain chemotherapy agents.
Arrow #2
Points to pancreas.
V20 of total lung
Cannot be determined from the graph.
DVHs confirmation
Confirms normal tissue tolerances are respected.
Sliding window vs. step-and-shoot
Sliding window likely has higher total monitor units.
Photon field abuts electron field
Results in photon side hot spot, electron side cold spot.
Arrow #1
Points to maxillary sinus.
Isocentric, parallel opposed oblique fields
May result in decreasing max dose as isocenter dose increases.
Increased skin dose in IMRT
Caused by use of high-energy photons.
Incorrectly labeled organ
Stomach in the CT scan.
increased skin dose in IMRT for prostate cancer
Factors include prone position, wedge under knees, use of high-energy photons, and
carbon fiber couch.
organ INCORRECTLY labeled in CT scan
Options are liver, stomach, left kidney, and aorta.
radiation beam delivery in step-and-shoot IMRT
The correct process involves MLC movement direction and beam delivery.
correct diagram for 90% and 105% distribution
, Options include diagrams labeled #1, #2, #3, and #5.
Arrow #2 points to
Options are descending thoracic aorta, carina, pulmonary trunk, and left pulmonary
artery.
Characteristics of MLC in current medical LINACs
Options include field sizes, isodose curves, field shapes, and leaf shape verification.
V20 from a DVH for both lungs
It represents the dose or volume relationship for lung exposure.
eliminating divergence into the lung for breast treatment
Options involve adjusting angles, matching beam edges, and central axis alignment.
physical penumbra width definition
It is the lateral distance between specific isodose curves at dmax level.
techniques to avoid cold spots in post-mastectomy chestwall treatment
Options include field matching, overlap, junction movement, and field gap at the skin
surface.
minimum nominal distance for tissue compensator placement
Options are 5.0 cm, 10.0 cm, 20.0 cm, and 25.0 cm.
X-ray contamination dose range when treating with electrons
Approximately ranges from 0.1% to 12%.
purpose of rounded ends on multi-leaf collimator leaves
They are used for specific functions related to field shaping and penumbra.
geometric penumbra statement
Options involve penumbra size, block-to-skin distance, source distance, and collimator
setting.
characteristics of a 12 MeV electron beam
Describes the depth characteristics and practical range of the beam.
calculation method for primary and scattered dose components
Options include Convolution superposition, Ray tracing, Manchester, and Monte Carlo.
effective field size calculation for a 10x10 field with 30% blocked
Determining the area for a specific field size and block percentage.
concept of equivalent squares in dose calculation
Understanding the concept and application of equivalent squares in dose calculations.
Ray tracing
A rendering technique for generating an image by tracing the path of light as pixels in an
image plane.
C. Manchester
A type of ionization chamber used for radiation dosimetry.
Monte Carlo
A computational algorithm used in radiation therapy for dose calculation and simulation.
Effective field size
The area of the radiation field that contributes to the dose delivery, accounting for
blocked areas.
Equivalent squares
Concept used in dose calculation where different field shapes have the same dosimetric
properties.
Monitor units
