Dosimetry 2, Sec. 1B questions with verified
answers
__________ is a method for figuring out what the doses would be off-
axis with curved surfaces. Ans✓✓✓ Effective SSD Method
__________ is also known as lateral tissue damage {not to be confused
with Tissue lateral effect} Ans✓✓✓ Edge effect
__________ is the probability of obtaining local control (not the same
thing as cure). Ans✓✓✓ Tumor Control Probability (TCP)
___________ is a function of rad and LET. Ans✓✓✓ Integral Dose
____________ are the most commonly used beam modifying device.
Ans✓✓✓ Wedge filters
_____________ are usually expressed as a percentage of the dose at a
reference point. Ans✓✓✓ Isodose curve
_______________ also affects the shape of isodose curves, therefore
source size, SSD, SDD have an effect on the shape. Ans✓✓✓ Geometric
penumbra
,- "a tissues preference for absorption." Ans✓✓✓ Differential
(preferential) absorption
- "Regardless of energy, it reads accurately and measures almost
independent of energy." Ans✓✓✓ flat energy response
- "the most common field arrangement." Ans✓✓✓ Parallel Opposed
Portals (POP)
- a low dose area inside the target volume. Ans✓✓✓ Cold Spot
- a measure of the total energy absorbed in the treated volume (a
product of dose and mass ) Ans✓✓✓ Integral Dose
- an area outside the target that receives a higher dose than the
specified target dose (again, must be a minimum of 2cm² volume)
Ans✓✓✓ Hot Spots
- areas of high dose near the surface in the periphery of the field that
are created by the flattening filter. Ans✓✓✓ "horns"
- demonstrates the dose variation across the field at a specified depth.
Ans✓✓✓ Beam profile
,- lines passing through points of equal dose. Ans✓✓✓ Isodose curve
- lowest dose in the target area. Ans✓✓✓ Minimum Target Dose
- makes the beam more uniform across the field. Ans✓✓✓ flattening
filter
- the absorbed dose that occurs most frequently within the target area.
Ans✓✓✓ Modal Target Dose
- the angle between the treatment fields. Ans✓✓✓ Hinge angle
- the angle of the tilt for an isodose curve at the CR at a specified depth,
historically the 50% isodose line. Ans✓✓✓ Wedge angle
- the average dose in the target area. Ans✓✓✓ Mean Target Dose
- the difference between the maximum and minimum intensity (dose)
across the central 80% portion of the beam. Ans✓✓✓ Flatness
- the highest dose in the target area (as long as its a minimum of 2cm²
volume) Ans✓✓✓ Maximum Target Dose
, - the maximum difference in intensity between two symmetrical points
(away from the CA) across the central 80% of the field. Ans✓✓✓
Symmetry
- the mid-value dose between the maximum TD (tumor dose) and
minimum TD. Ans✓✓✓ Median Target Dose
- the number and angle of beams used. Ans✓✓✓ Field Arrangements
- the only field arrangement available for electrons and Kv x-ray.
Ans✓✓✓ Single Field
- the point of intersection of the collimator and the gantry axis of
rotation. Ans✓✓✓ Isocenter
- the simplest and easiest field arrangement Ans✓✓✓ Single Field
- two fields 180° apart super imposing upon each other. Ans✓✓✓
Parallel Opposed Portals (POP)
"horns" are especially prominent in ___________ machines. Ans✓✓✓
cobalt
answers
__________ is a method for figuring out what the doses would be off-
axis with curved surfaces. Ans✓✓✓ Effective SSD Method
__________ is also known as lateral tissue damage {not to be confused
with Tissue lateral effect} Ans✓✓✓ Edge effect
__________ is the probability of obtaining local control (not the same
thing as cure). Ans✓✓✓ Tumor Control Probability (TCP)
___________ is a function of rad and LET. Ans✓✓✓ Integral Dose
____________ are the most commonly used beam modifying device.
Ans✓✓✓ Wedge filters
_____________ are usually expressed as a percentage of the dose at a
reference point. Ans✓✓✓ Isodose curve
_______________ also affects the shape of isodose curves, therefore
source size, SSD, SDD have an effect on the shape. Ans✓✓✓ Geometric
penumbra
,- "a tissues preference for absorption." Ans✓✓✓ Differential
(preferential) absorption
- "Regardless of energy, it reads accurately and measures almost
independent of energy." Ans✓✓✓ flat energy response
- "the most common field arrangement." Ans✓✓✓ Parallel Opposed
Portals (POP)
- a low dose area inside the target volume. Ans✓✓✓ Cold Spot
- a measure of the total energy absorbed in the treated volume (a
product of dose and mass ) Ans✓✓✓ Integral Dose
- an area outside the target that receives a higher dose than the
specified target dose (again, must be a minimum of 2cm² volume)
Ans✓✓✓ Hot Spots
- areas of high dose near the surface in the periphery of the field that
are created by the flattening filter. Ans✓✓✓ "horns"
- demonstrates the dose variation across the field at a specified depth.
Ans✓✓✓ Beam profile
,- lines passing through points of equal dose. Ans✓✓✓ Isodose curve
- lowest dose in the target area. Ans✓✓✓ Minimum Target Dose
- makes the beam more uniform across the field. Ans✓✓✓ flattening
filter
- the absorbed dose that occurs most frequently within the target area.
Ans✓✓✓ Modal Target Dose
- the angle between the treatment fields. Ans✓✓✓ Hinge angle
- the angle of the tilt for an isodose curve at the CR at a specified depth,
historically the 50% isodose line. Ans✓✓✓ Wedge angle
- the average dose in the target area. Ans✓✓✓ Mean Target Dose
- the difference between the maximum and minimum intensity (dose)
across the central 80% portion of the beam. Ans✓✓✓ Flatness
- the highest dose in the target area (as long as its a minimum of 2cm²
volume) Ans✓✓✓ Maximum Target Dose
, - the maximum difference in intensity between two symmetrical points
(away from the CA) across the central 80% of the field. Ans✓✓✓
Symmetry
- the mid-value dose between the maximum TD (tumor dose) and
minimum TD. Ans✓✓✓ Median Target Dose
- the number and angle of beams used. Ans✓✓✓ Field Arrangements
- the only field arrangement available for electrons and Kv x-ray.
Ans✓✓✓ Single Field
- the point of intersection of the collimator and the gantry axis of
rotation. Ans✓✓✓ Isocenter
- the simplest and easiest field arrangement Ans✓✓✓ Single Field
- two fields 180° apart super imposing upon each other. Ans✓✓✓
Parallel Opposed Portals (POP)
"horns" are especially prominent in ___________ machines. Ans✓✓✓
cobalt
