Question 1

Radiation dose for DXA scans is:&#10;A) twice as much as for a diagnostic lumbar x-ray.&#10;B) half as much as for a lumbar CT examination.&#10;C) similar to natural background radiation.&#10;D) similar to a diagnostic hand x-ray.

Accepted Answer

DXA scans have a very low radiation dose, comparable to the amount of natural background radiation one would receive in a day.

Question 2

Peak bone mass is reached at about age _____ years.&#10;A) 10 to 20&#10;B) 20 to 30&#10;C) 30 to 40&#10;D) 40 to 50

Accepted Answer

Peak bone mass is typically reached between the ages of 20 to 30 years, when bones have reached their maximum strength and density.

Question 3

The measurement of bone density uses two different beam energies,allowing the separation of soft tissue and bone due to:&#10;A) filtration differences in the beam.&#10;B) mass attenuation coefficient differences.&#10;C) BMD population calculations.&#10;D) the two-dimensional area.

Accepted Answer

The measurement of bone density uses dual-energy X-ray absorptiometry (DEXA), which relies on differences in the mass attenuation coefficients of bone and soft tissue at different X-ray energies to distinguish between them.

Question 4

The bone densitometry parameters reported on the DXA printouts include which two of the following? (Select all that apply.) A) Area in centimeters squared (cm²) B) Mass attenuation coefficient C) BMD in g/cm² D) Volumetric density

Accepted Answer

DXA printouts typically report the area in cm² and BMD (Bone Mineral Density) in g/cm² as part of the bone densitometry parameters.

Question 5

Accuracy in bone densitometry relates to the ability of the system to:&#10;A) measure the true value of an object.&#10;B) reproduce the same results in repeat measurements of the same object.&#10;C) reflect the bone measurement by the scanner software.&#10;D) measure the variability of the spread of data values around the mean.

Accepted Answer

Accuracy in bone densitometry refers to how closely the measurement reflects the true value of the bone density, which is described in choice A.

Question 6

The T-score is used to assess:&#10;A) the reference population.&#10;B) fracture risk for the patient.&#10;C) if the measured BMD is reasonable.&#10;D) patient age and bone loss.

Accepted Answer

The T-score is used to assess fracture risk for the patient by comparing their bone mineral density (BMD) to the average peak BMD of a healthy young adult.

Question 7

Precision relates to the ability of the system to:&#10;A) measure the true value of an object.&#10;B) reproduce the same results in repeat measurements of the same object.&#10;C) reflect the bone measurement by the scanner software.&#10;D) measure the variability of the spread of data values around the mean.

Accepted Answer

Precision refers to the consistency and reproducibility of measurements, meaning the ability to obtain the same results under unchanged conditions.

Question 8

DXA calculations are based on:&#10;A) body position and bone density.&#10;B) bone density only.&#10;C) soft tissue only.&#10;D) soft tissue and bone.

Accepted Answer

DXA (Dual-energy X-ray Absorptiometry) calculations are based on both soft tissue and bone, as it measures bone mineral density and also assesses body composition by differentiating between bone mass, lean tissue, and fat tissue.

Question 9

The most common osteoporotic fracture is found in the:&#10;A) hips.&#10;B) femurs.&#10;C) vertebrae.&#10;D) ankles.

Accepted Answer

Vertebral fractures are the most common type of osteoporotic fractures, often occurring due to the weakening of the bones in the spine.

Question 10

What is the chief benefit of using a high and low x-ray energy source with a DXA system?&#10;A) Reduces patient dose significantly.&#10;B) Reduces wear and tear on the x-ray tube to change energies.&#10;C) Demonstrates attenuation difference between bone and soft tissue.&#10;D) Reduces postprocessing time of bone for the digital image.

Accepted Answer

Using high and low x-ray energy sources in a DXA system helps differentiate between bone and soft tissue by measuring their different attenuation levels, which is crucial for accurate bone density assessment.

Question 11

The Z-score is used to determine:&#10;A) the reference population.&#10;B) fracture risk for the patient.&#10;C) if the measured BMD is reasonable.&#10;D) patient age and bone loss.

Accepted Answer

The answer of The Z-score is used to determine:&#10;A) the...

Question 12

The purpose of bone densitometry is to:&#10;A) establish the diagnosis of osteoporosis.&#10;B) assess the response to osteoporosis therapy.&#10;C) measure bone mineral density.&#10;D) do all of the above.

Accepted Answer

The answer of The purpose of bone densitometry is to:&#10;A)...

Question 13

Bone-destroying cells are called:&#10;A) osteoblasts.&#10;B) osteoclasts.&#10;C) cancellous.&#10;D) cortical.

Accepted Answer

The answer of Bone-destroying cells are called:&#10;A) osteoblasts.&#10;B) osteoclasts.&#10;C) cancellous.&#10;D)...

Question 14

All are risk factors for osteoporosis,except:&#10;A) daily physical activity.&#10;B) alcohol consumption.&#10;C) low body weight.&#10;D) low calcium intake.

Accepted Answer

The answer of All are risk factors for osteoporosis,except:&#10;A) daily...

Question 15

Which vertebral region(s)is (are)analyzed during a DXA scan?&#10;A) T12&#10;B) T7 to L1&#10;C) L1 to L5&#10;D) L4 to S2

Accepted Answer

The answer of Which vertebral region(s)is (are)analyzed during a DXA...

Question 16

A BMD measurement from a patient is most useful when it can be compared statistically to:&#10;A) the same patient age population.&#10;B) a population living in the same area.&#10;C) multiple scans on the same patient.&#10;D) an appropriate sex-matched reference population.

Accepted Answer

The answer of A BMD measurement from a patient is...

Deck 19: Bone Densitometry