H.Quality assurance procedures

Question 1

______systems provides safety for patient, staff, and machine

Answer 1

Interiock

Question 2

_______interlock : Radiation beam is unable to turn on when the door to the treatment room is open

Answer 2

door interlock

Question 2

___ are either turned off or not able to turn on when conditions are Unsafe

Answer 2

machines

Question 2

_______interlocks: Stops motion of the gantry when the head of the gantry or imaging systems are too close to the patient or devices

Answer 2

collisions interlocks

Question 3

Interlock systems have a “functional” tolerance . This means they

Answer 3

work or do not work

Question 4

Patient devices like blocks, wedges, cones, and compensators are programmed with a code » An interlock will show if the device code does not match the

Answer 4

code planned for that specific patient

Question 5

How often is door interlock checked

Answer 5

daily

Question 6

How often is MV, KV, and CBCT (EPID) Collision interlock checked

Answer 6

daily

Question 6

How often is laser guard interlock checked

Answer 6

monthly

Question 7

How often is Electron Applicator interlock checked

Answer 7

Annually

Question 8

A light turns on when the linear accelerator is on or if a radiation source is

Answer 8

exposed

Question 8

______ are switches that terminate the radiation beam and shut down the machine

Answer 8

emergency switches

Question 9

emergency switches are checked

Answer 9

monthly

Question 10

Laser alignment is a daily check because it can affect

Answer 10

geometric parameters

Question 11

IMRT laser tolerance

Answer 11

1.5mm

Question 11

SRS/ SBRT laser tolerance

Answer 11

1 mm

Question 12

_______ is circulated throughout the linear accelerator to cool internal parts such as the accelerator waveguide, source of microwave power, x-ray target, and bending magnets

Answer 12

cooling water

Question 13

The temperature of the waveguide should be constant at

Answer 13

40 ± 5 degree C

Question 14

Compressed air is used to move the target, control the energy switch, and control the locking system on the carrousel
» A common pressure used is

Answer 14

45-50 psi

Question 15

Sulfur hexafluoride (SF6) is a pressurized gas used to prevent arcing within the waveguide » _____ psi is required

Answer 15

25 to 32 PSI

Question 16

Electrical and mechanical hazards can occur if the software within the

Answer 16

machine fails

Question 17

According to the FDA, a ____ hazard can cause death or serious injury

Answer 17

class 1

Question 18

A ____ injury is a hazard that has little risk of causing serious injury

Answer 18

Class II

Question 19

Examples of _____ include: radiation overdose or underdose due to a faulty machine, dose outside the radiation field, patient/machine collision, and incorrect beam energy

Answer 19

hazards

Question 20

_____ systems have their own coordinate systems, but they are calibrated to match treatment coordinate systems

Answer 20

imaging

Question 21

Imaging » Tolerance for non-SRS/SBRT =

Answer 21

2mm

Question 22

Imaging » Tolerance for SRS/SBRT =

Answer 22

1mm

Question 23

Audio and visual systems are safety checks that are checked

Answer 23

daily

Question 24

At least one audio channel and one video channel must be

Answer 24

functioning to treat

Question 25

what does functional test mean

Answer 25

Works or does not work

Question 26

Safety lights are a ___ test

Answer 26

functional

Question 27

Image quality is important in defining target volumes as well as other organs at risk for treatment planning purposes. Image quality and performance is tested using a

Answer 27

water phantom provided by the manufacturer of the CT sim machhine

Question 28

Image noise on CT machine should be checke

Answer 28

daily

Question 29

CT numbers (Hounsfield units) are checked

Answer 29

daily and monthly

Question 30

In all x-ray tubes, warming up the anode is an important step to prolong the

Answer 30

tube life

Question 31

For CT scanners Tube warmup should be performed each morning and before a scan if the machine hasn't been used for

Answer 31

2 hours

Question 32

Beam output can be measured by devices that have

Answer 32

multiple ion chambers or diodes

Question 33

Checks beam output on the central

Answer 33

axis and off axis

Question 34

Linear accelerator output is checked

Answer 34

daily, monthly, and annually for each beam energy

Question 35

Monthly and annual output tolerance is ± 2 percent for

Answer 35

electron and photon therapy

Question 36

___________ can have an effect on the ion chambers if they are not sealed because it will affect the density of the air within the chambers

Answer 36

Atmospheric temperature and pressure

Question 37

Pressure and exposure reading have a

Answer 37

direct relationship

Question 38

As pressure is increased, the output reading is

Answer 38

increased

Question 38

As pressure is decreased, the output reading is

Answer 38

decreased

Question 39

Temperature and exposure reading have an

Answer 39

indirect relationship

Question 40

As temperature is decreased, the output reading is

Answer 40

increased

Question 41

As temperature is increased, the output reading is

Answer 41

decreased

Question 42

A ____ factor must be used for temperature and pressure when calculating and measuring dose output if the ion chambers are not sealed and temperature and pressure vary from specific conditions

Answer 42

correction

Question 43

The light field represents the _____. so the The light field should be identical to it.

Answer 43

radiation field

Question 43

A light field Mechanical check with a tolerance of

Answer 43

2 mm or 1% on a side symmetric fields

Question 44

To verify the calibration of leaf positions, use the _______ test

Answer 44

picket fence test

Question 45

Field size tolerance is

Answer 45

2mm

Question 45

The field size indicated on the console must match what is ________. This can be tested by measuring the field on the table with a ruler at isocenter (100 SAD) Test for field sizes ranging from 0 x 0 cm to 40 x 40 cm

Answer 45

projected on the patient

Question 46

Multileaf collimator performance is verified with

Answer 46

radiographic imaging

Question 47

Leaf position has a ____ tolerance

Answer 47

1 mm

Question 47

According to the Task Group 142 Report, picket fence test should be performed weekly on machines that perform ____

Answer 47

IMRT

Question 48

Non-IMRT machines are also checked monthly, but have a ____ tolerance for leafs

Answer 48

2mm

Question 49

______ lasers are checked daily

Answer 49

alignment

Question 50

Lasers must point at and intersect at the

Answer 50

isocenter

Question 51

Side wall lasers must be

Answer 51

collinear

Question 52

Laser Tolerance ± ____ for non-IMRT machines

Answer 52

2mm

Question 53

The _______ Test can be used to verify laser accuracy

Answer 53

Winston-Lutz

Question 54

Winston-Lutz is more common for machines than perfrom

Answer 54

SRS

Question 55

Winston-Lutz test has ___ tolerance

Answer 55

2mm

Question 56

To properly check that the gantry rotation for a patient's treatment is safe, a test run (dry run) of the gantry movement should be performed prior to treatment to make sure there are

Answer 56

no collisions with the patient, table, or any other devices

Question 57

Tolerance for gantry and collimator angle is

Answer 57

1 degree

Question 58

There are limit switches for the gantry to avoid over rotation of the gantry. The gantry cannot rotate

Answer 58

infinitely

Question 59

Mechanical tolerances for linear measurements are typically ±___

Answer 59

2mm

Question 60

Tolerances for angles are typically

Answer 60

1 degree

Question 61

Dosimetric monthly checks for output have tolerances of

Answer 61

2%

Question 62

____checks are "functional" and either work or don't

Answer 62

safety

Question 63

____measurements should be permanently recorded and evaluated frequently

Answer 63

QA

Question 64

Departmental guidelines should outline the proper steps to take when test results are out of _____

Answer 64

tolerance