Week #13

Question 1

What are the 3 main components of QC for fluoro equipment?

Answer 1

Visual inspection
Environmental inspection
Performance testing

Question 2

According to SC35, how often should collimator operation, locks, table motion, angulation, compression devices, chronometer, protective devices be tested?

Answer 2

Quarterly

Question 3

According to SC35 how often should collimator operation be evaluated to ensure the dimensions of the xray field do not exceed the area of the II

Answer 3

Annually

Question 4

According to SC35, what percent should the xray field not exceed the area of the II by the SID?

Answer 4

3%

Question 5

What lead equivalent should the protective curtain contain?

Answer 5

0.25mm

Question 6

What percentage should the table angulation and motion be accurate within?

Answer 6

2 degrees

Question 7

What indicator should be present when inspecting the high level irradiation control?

Answer 7

Ensure that an audible signal is present when in use

Question 8

According to SC35, what is the limit for reproducibility variance between exposures?
What is the testing frequency?

Answer 8

CV less than or equal to 0.05
Each exposure within 15% of the mean
Annual

Question 9

At 70 kv, what is the minimum half value layer of aluminum for fluoro?

Answer 9

2.5 mm

Question 10

How is kvp accuracy tested in fluoro?

Answer 10

Expose a digital kvp meter under fluoro

Question 11

According to HARP what is the testing frequency and acceptance limit for kvp accuracy?

Answer 11

Semi annual
8%

Question 12

According to SC35 what is the testing frequency and acceptance limit for kvp accuracy?

Answer 12

Annual
10% for xray tube voltage
20% for xray tube current

Question 13

Testing involves a series of fluoroscopic exposures, each at double the mA of the previous

Answer 13

mA linearity

Question 14

What is the required testing frequency for ma linearity according to SC35?

Answer 14

Annual

Question 15

At what percent of maximum heat should the alarm be activated when exposing a homogenous phantom under fluoro? What is this testing?

Answer 15

When 75% of maximum heat is achieved

Xray tube heat sensor

Question 16

The ability to resolve objects in a resultant image when the difference in the attenuation between the objects and the background is large compared to noise

Answer 16

Spatial resolution

Question 17

Ability to resolve small, black and white objects

Answer 17

High contrast resolution

Question 18

How is testing done for high contrast resolution?

Answer 18

Testing involves imaging a testing tool under fluoro
Depending on the size of the II, a minimum size mesh should be visualized
Follow manufacturer guidelines

Question 19

Ability to resolve relatively large objects with similar density

Answer 19

Low contrast resolution

Question 20

What is the minimum source to skin distance for fixed or stationary units?

Answer 20

Not less than 30cm or 15”

Question 21

What is the minimum source to skin distance for mobile units?

Answer 21

Not less than 30cm or 12”

Question 22

What is the minimum source to skin distance for specialized units?

Answer 22

Not less than 20cm or 8” for special applications that would be impossible to achieve at a minimum of 30cm or 38cm

Question 23

Scattered or reflected light in the output phosphor; causes an increase in brightness on the image

Answer 23

Veiling glare

Question 24

Occurs due to projecting image curved surface to flat surface, such as input phosphor to output phosphor (distortion is greater towards the lateral portion of the image)

Answer 24

Pincushion distortion

Question 25

Same as pincushion but magnification occurs at the centre

Answer 25

Barrel distortion

Question 26

A decrease in image brightness at the lateral portions of the image - caused by a combination of pincushion distortion and the coupling of the television camera to the output phosphor

Answer 26

Vignetting

Question 27

Warping of the image along an S shaped axis and is the result of strong magnetic fields changing the trajectory of the electrons moving across the image intensifier tube

Answer 27

S distortion

Question 28

What is used for testing of distortion?

Answer 28

Wire mesh tool under fluoro

Question 29

Can be due to quantum mottle or electronic noise present on fluoro monitor

Answer 29

Image noise

Question 30

What can be done if quantum mottle is identified on an image?

Answer 30

ma can be increased

Question 31

How do you test for image noise?

Answer 31

Expose a phantom at lowest mA and 80kvp. Increase mA to maximum value, if noise goes away it is quantum mottle, if it does not it is electronic noise

Question 32

Ability of imaging system to display events occurring close together in time as separate events

Answer 32

Temporal resolution

Question 33

Continuation of persistence of image; can blur objects as the II or object is moved

Answer 33

Image lag - directly influences temporal resolution

Question 34

What is entrance exposure referred to as?

Answer 34

Air Kerma rate of radioscopic exposure

Question 35

Max. Air kerma When equipment is not fitted with an automatic intensity control

Answer 35

50mgy/min

Question 36

Max. Air kerma When equipment is fitted with an automatic intensity control

Answer 36

100mgy/min

Question 37

Max. Air kerma When equipment is fitted with both an automatic intensity control and a high level irradiation control when the latter is activated

Answer 37

150mgy/min

Question 38

How do you test the automatic brightness control?

Answer 38

Place a dosimeter between a homogenous phantom and the xray source. Double the phantom thickness and repeat exposure. ***the exposure measurement should be approximately double the first measurement ***

Question 39

According to HARP, what shall every fluoroscopic xray machine be equipped with?

Answer 39

-an audible signal that indicates completion of any preset time of use up to a maximum of 5 minutes -a shield of at least 0.25mm lead equivalent at 100kvp

Question 40

What is the exposure rate limit for a machine that uses a zinc cadmium suplphide input phosphor?

Answer 40

-max. Entrance exposure of 12.5R/min -entrance exposure rate of 5R/min for average patient

Question 41

What is the exposure rate limit for a machine that has a cesium iodide input phosphor?

Answer 41

-max. Exposure rate of 10R/min -entrance exposure rate of 2.5R/min for an average patient

Question 42

According to HARP , what is the testing frequency for: -max patient entrance exposure rate -resolution -limit timer -automatic brightness control

Answer 42

Every 6 months and upon servicing the machine