(*-*) EXPOSURE LIMITIS, SHIELDING, QA Flashcards

1
Q

which barrier is where the useful beam hits?

A

primary

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2
Q

which barrier is where the scatter and leakage hits?

A

secondary barrier

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3
Q

restricted/controlled areas (like control room) are limited to ____ msv/wk or ____ msv/yr

A

.5 msv/wk
or 5 msv/yr

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4
Q

unrestricted/uncontrolled areas (like waiting room) are limited to ____ msv/wk or ___ msv/yr

A

.02 msv/wk or 1 msv/yr

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5
Q

who keeps the personnel dosimetry records?

A

RSO (radiation safety officer)

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6
Q

“monitored if expected to receive __% or more of effective dose”

A

10% or more of effective dose

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7
Q

label which is the PRIMARY BARRIER and which is the SECONDARY barrier

A
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8
Q

what interlocks are checked daily?

A

-door
- EPID collision
-safety lights
-audio/visual
-radiation output
-laser alignment
-ODI
-collimator indicator agreement
-imaging QA
-CT water phantom tests (noise and CT numbers/HU)

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9
Q

what interlocks are checked monthly?

A

-gantry collision
-emergency off buttons
-flatness and symmetry
-light and radiation field agreement

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10
Q

what interlocks are checked annually?

A

-electron cones
-gantry (mechanical iso)
-collimator (mechanical iso)
-radiation isocenter

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11
Q

what does a “functional” tolerance mean?

A

means it works, or it does not work - if it does not work, we cannot treat

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12
Q

safety lights, audio/visual, and emergency off buttons have what tolerance?

A

functional tolerance

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13
Q

safety lights for a LINAC say what? for HDR say what?

A

LINAC - beam is ON
HDR - source is exposed

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14
Q

what is most common malfunction of safety lights not turning on?

A

light bulb being out

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15
Q

if emergency off button fails to turn beam off, what is next step?

A

circuit breaker switch

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16
Q

each LINAC should have at least how many visuals? and a what kind of audio?

A

2
and a two-way audio system

17
Q

with cameras, we have what kind of visual of LINAC treatment room. Whereas a CT room has what kind of visual?

A

an indirect visual

a CT room has a direct visual since kv source is low enough

18
Q

what interlocks are checked weekly?

A

-MLC performance (picket fence test)

19
Q

the “star pattern test” tests for what?

A

Radiation Isocenter – checks gantry, collimator, and couch

20
Q

LEVEL 1 requires what?

A

can still trt but inspect

21
Q

LEVEL 2 requires what?

A

can still trt but schedule maintenance ASAP

22
Q

LEVEL 3 requires what?

A

do not trt - immediate action needed

23
Q

1 TVL = ____ HVL

24
Q

how much lead is in lead apron?

25
flattening filter is used for photons or electrons? and is in shape of what?
photons and is in shape of cone - made of high Z material
26
high Z material = _________
absorption
27
intention of flattening filter is what?
to create a flat, even, dose distribution
28
intention of scattering foil is what? what is the material?
spread e- beam out -copper or lead
29
primary collimators are __moveable/stationary__
stationary
30
secondary collimators are __moveable/stationary__
moveable & asymm
31
field size ranges from __x__ to __x___ of secondary collimators
0x0 to 40x40
32
MLCs can transmit <__% of beam
<2%
33
ODI is located __within/outside__ treatment head
outside treatment... but on it ... ODI projects our numbers
34
you can or cannot adjust primary collimators?
cannot!
35
collimating jaws and mlcs are made of what?
tungsten