Module 14

Question 1

What filter do GE lunar systems use

Answer 1

Cerium

Question 2

The cerium filter spectrum at 80KV produces 2 photo electric peaks at about what value

Answer 2

40keV and 70keV

Question 3

Norland Swissray uses what type of filter

Answer 3

Samarium

Question 4

The Samarium filter spectrum at 100kV a low energy peak and high energy peak at what range

Answer 4

47keV low, Less than 100keV high

Question 5

Hologic scanners use what type of filter system

Answer 5

Energy switching xray beam between 100 and 140kVp

Question 6

Two dimensional scan area is also known as

Answer 6

Projectional or areal

Question 7

Three dimensional scans are also known as

Answer 7

Volumetric

Question 8

A decrease in the BMC also results in a decrease in

Answer 8

BMD

Question 9

A decrease in area causes an increase in

Answer 9

BMD

Question 10

This is the sum of the data values, divided by the number of values

Answer 10

Mean

Question 11

Measure of variability, it shows how spread out the data is around the mean

Answer 11

Standard deviation

Question 12

This is A statistic that helps compare a variability between different datasets whether or not they have the same mean

Answer 12

Percent coefficient of variation

Question 13

This refers to an inconvenient anomaly in which T scores from different atomic sites within the same patient fall into different diagnostic classifications

Answer 13

Discordance

Question 14

This describes how closely a measurement approximates with things that is measuring

Answer 14

Accuracy

Question 15

This measures how closely a test`s results approximate the correct value

Answer 15

Trueness

Question 16

This is the measure of how likely a test is to achieve the same result when repeated on the same subject in the same conditions

Answer 16

Precision

Question 17

This is used to describe the consistency of measurement

Answer 17

Precision

Question 18

This is used to describe how closely it measures the expected values

Answer 18

Trueness

Question 19

What are the rules for in vivo scans

Answer 19

Either 15 patients 3 times each or 30 patients 2 times each

Question 20

What is the maximum acceptable precision error for technologies performing a lumbar spine scan

Answer 20

1.9% with an associated LSC of 5.3%

Question 21

What is the maximum precision error for a scan of the total hip

Answer 21

1.8% with an LSC of 5%

Question 22

What is the maximum precision error for a scan of the femoral neck

Answer 22

2.5% with an LSC of 6.9%

Question 23

How do you cross calibrate machines

Answer 23

Scan 30 patients representative of the facility’s patient population on the original system and then twice on the new system for this method all scan should be completed within 60 days

Question 24

This is a measure of bone micro texture and is a marker for the risk of osteoprosis

Answer 24

Trabecular bone score

Question 25

What does QC on DXA units consist of

Answer 25

Scanner calibration test, Phantom test, and precision assessments

Question 26

This is a comprehensive program that sets guidelines for monitoring and evaluating medical systems. This includes the scanner's function and the technologies technique

Answer 26

QA, quality assurance

Question 27

When values are plotted mathematical rules are applied to detect any failures that indicate a change in a machine's performance the result of this QC is called what

Answer 27

Shewhart or control chart

Question 28

This is a statistical method of Quality control, the purpose of this is to evaluate scanner stability

Answer 28

Shewhart rules

Question 29

The upper lower controls on control chart represent plus and minus ____ percent of the main

Answer 29

1.5

Question 30

What type of Phantom does a hologic unit use

Answer 30

Anthropomorphic (made of hydroxyapatite)

Question 31

What type of spine Phantom does GE use

Answer 31

Aluminum

Question 32

What are the 3 basic statistical terms used in analysis of QC results

Answer 32

The mean, the standard deviation, and the percent coefficient variation

Question 33

Precision assessment measures

Answer 33

Reproducibility

Question 34

True or false DXA scanning exposes patients to < one day's worth of natural background radiation

Answer 34

True

Question 35

Which skeletal site offers the highest precision in the most rapid response treatment

Answer 35

Lumbar spine

Question 36

When should cross calibration be performed

Answer 36

When changing DXA hardware

Question 37

How many Phantom scans must be performed to verify Phantom BMD following scanner maintenance

Answer 37

10

Question 38

Serial scanning of a patient's bone mineral density values can be used to monitor

Answer 38

Response to therapy

Question 39

What is the main purpose of Shewhart rules as they apply to bone Densitometry

Answer 39

Evaluating scanner precision