Module 5

Question 1

BD takes advantage of X-ray energy and body composition process by using a blank technique

Answer 1

Subtraction

Question 2

What type of equipment used a water bath to emulate soft tissue during scanning

Answer 2

Absorptiometry scanners

Question 3

How is the value of bmd calculated

Answer 3

Determining the BMC and dividing it by the area of bone that was scanned

Question 4

Refers to the binding energy of the K shell electron which varies for different materials

Answer 4

K edge

Question 5

What type of filter does the GE system use

Answer 5

CERIUM

Question 6

What type of filter does a Norland system use

Answer 6

Samarium

Question 7

What type of energy does hologic use

Answer 7

A patent energy switch in system to generate beams with the 2 distinct photo electric pics

Question 8

Where is the detector

Answer 8

The scanner arm that passes over the patient

Question 9

What are 3 common physics problems that occur with DXA

Answer 9

Beam hardening, scintillating detector pillup, and cross over

Question 10

This problem is from increased absorption shifts the distribution of photons towards high energy x-rays

Answer 10

Is beam hardening

Question 11

This affects K edge filtration systems because they pulse counting detector can only process one photo at a time, if it’s not processed quickly enough and incoming photon can be missed

Answer 11

Scintillating detector pile up

Question 12

This problem occurs because high energy photons can sometimes lose energy when passing through the body and be counted as low energy photons by the detector

Answer 12

Crossover

Question 13

Travels back-and-forth in a rectilnear pattern across the scan area

Answer 13

Pencil beam

Question 14

This scanner has a slit shaped colometer and a multi element detector the scanning motion only moves along one access

Answer 14

Is fan beam or fan array

Question 15

What is a Disadvantage of fan beam technology

Answer 15

It can magnify and distort the outer edges of the scan area

Question 16

This is a process by which the lateral projections of the spine are analyzed and measured, Answer is not VFA

Answer 16

Morphometric Absorptiometry

Question 17

The ability of a test to measure the correct value of the thing it’s measuring

Answer 17

Accuracy

Question 18

The likelihood a test can achieve the same result when It is repeated on the same subject and under the same conditions

Answer 18

Precision

Question 19

How is the operator’s precision assist through in vivo

Answer 19

Scan of 15 patients 3 times or 30 patients 2 times

Question 20

This error is expressed mathematically as a standard deviation with the most common results falling in the middle of a range and the less frequent results to the edge

Answer 20

Random error

Question 21

A wide standard deviation indicates

Answer 21

Low precision

Question 22

This measures how closely the results of the test match an external reference value

Answer 22

Trueness

Question 23

What are the 2 factors of in vivo studies

Answer 23

The variability of a patient’s anatomy and the skill and attentiveness of the technologist

Question 24

LSC

Answer 24

Least significant change is the minimum change in a patient’s measured bone density that reflects a real change in the patient rather than an error by the technologist or scanner

Question 25

The minimum accuracy for the lumbar spine is ____ part technologist with an associated LSC of _____

Answer 25

1.9% and 5.3%

Question 26

The minimum Accuracy for a scan of a total hip is ______ with a LSC of ______

Answer 26

1.8% and 5%

Question 27

The minimum accuracy for a scan of the femoral neck is _____ with an LSC of _____

Answer 27

2.5% and 6.9%

Question 28

What are the 4 speeds of the hologic system

Answer 28

Fast array 30 seconds
array 60 seconds
high definition a 120 seconds
Turbo 10 seconds

Question 29

What modes do GE And Norland have

Answer 29

Thick standard thin and quick view modes

Question 30

Slow shifts in blank are a much greater concern because they can affect many patient scans before being noticed

Answer 30

Accuracy

Question 31

DEXA uses a blank technique that eliminates soft tissue from the scan results

Answer 31

Subtraction

Question 32

K edge filter crossover occurs when high energy photons lose energy passing through the body and are

Answer 32

Registered as photons from the low energy beam

Question 33

What value measures how closely the results of the test match an external reference value

Answer 33

Truness

Question 34

What type of patient is most appropriate for precision testing

Answer 34

One that represents the facility’s population

Question 35

DXA equipment calibration effects which values

Answer 35

Precision and truness