linac/sim QA Flashcards
daily x-ray & e- output constancy frequency, tolerance
3%
monthly linac output tolerance
+/- 2%
Gantry indicator frequency, tolerance
Monthly 1 deg
Collimator indicator frequency, tolerance
Monthly 1 deg
Light intensity frequency
Monthly
Radiation light congruence frequency
Monthly
Field light dependence frequency
Annual
Off axis ratio frequency
Annual
wedge, cone, tray frequency
Annual
Linearity frequency, tolerance
Annual 1%
Output vs angle frequency
Annual
ISO checks frequency
Annual
simulator gantry/coll indicator tolerance
1 deg
sim annual
isocenter, sag, vert, travel couch
ct sim gantry tilt tolerance
1 deg
ct sim scan localization tolerance
1mm
e- flatness tolerance, frequency
3% monthly
transmission
annual
transmission frequency
annual
PDD beam quality defined for photons at
10 cm
depth of calibration for photons
10cm
beam quality defined for e- at
R50
depth of calibration for e-
reference depth
beam flatness specified @ what depth
10 cm
mlc picket fence test detects
leaf positions out of calibration
check sums is qa for testing the integrity of
computer files
IMRT primary barrier shielding vs non-IMRT
unchanged
IMRT leakage barrier shielding increased by ? HVL
2-3
IMRT maze door barrier shielding increased by ? HVL
2-3
UT- linac jaws transmission tolerance
1%
UT mlc transmission interleaf tolerance
2%
UT- cerrobend block transmission tolerance
3-5%
UT- linac calibration protocol for dosimetry
TG 21 old; TG 51 new
UT- rad measurement equip calibration frequency
every 2 yrs
UT- mechanical tolerance
2 mm
UT- rad/light coincidence tolerance
2mm
QA split field technique used for
beam misalignment
CDC is a gov’t agency involved in
helping hospital infection control
intermediate billing # ports
3 or more converging ports
complex billing # tx areas
3+ tx areas
split field requires longitudinal displacement of collimator for jaw symmetry rotated ?
180 deg
machinist dial indicator for qa used for
jaw symmetry
when detector receives more radiation than capable
point of saturation
calibration ensures radiation detectors able to
record values close to actual reading
acceptable tolerance for field flatness
+/- 3%
indicators for sim checked how frequently
monthly
cross hair for sim checked how frequently
monthly
collision for sim checked how frequently
monthly
coincidence for sim checked how frequently
monthly
focal spot for sim checked how frequently
monthly
film processor for sim checked how frequently
monthly
sagittal for sim checked how frequently
annually
vert for sim checked how frequently
annually
travel couch for sim checked how frequently
annually
UT xray flatness tolerance
3% of central 80% of field @ 10 cm
UT x-ray & e- symmetry tolerance
2% of central 80% of field @ 10cm
UT mlc transmission intraleaf tolerance
4%
UT- linac calibration protocol for mechanical
TG-40
split field technique checks what
opposite field radiation/light incongruence (mirror misalignment)