______________________ used a grading system to attempt to quantify the severity of bone loss in the spine and femur.

a) Plain radiographs

b) DXA scan

c) Quantitative Ultrasound

d) Qualitative Morphometry

d) Qualitative Morphometry

Qualitative Morphometry used a grading system to attempt to quantify the severity of bone loss.

Dual-energy X-Ray absorptiometry (DXA) is:

a) Considered today's gold standard in bone density measurement

b) Has two peak energies to separate bone from soft tissue

c) Has improved precision because there are no isotopes that can decay.

d) All the above

d) All the above

DXA is today's gold standard in bone density measurement. The scanner is easy and inexpensive to maintain, the exam is painless, quick and accurate, and the radiation dose to the patient is minimal.

Some DXA units employ voltage switching or alternating pulsed to the X-ray source to generate _______________________.

a) An X-ray beam

b) One single energy of 70 KV

c) Dual energies, 70 KV to 140 KV

d) Dual energies, 140 KV to 220 KV

c) Dual energies, 70 KV to 140 KV

Voltage switching generates dual energies of 70 KV and 140 KV. This method give the scanner the dual energies to differentiate between soft tissue and bone.

What type of calibration is used with voltage switching units?

a) Continuous internal calibration with rotating wheel or drum

b) External calibration built into a phantom

c) Calibration included in system software

d) No calibration is needed because of the method of dual-energy production

a) Continuous internal calibration with rotating wheel or drum

The correct answer is continuous internal calibration with a rotating wheel or drum. No manual calibration is needed with these systems.

What is rare earth K-edge filtering?

a) An isotope used in SPA

b) A K-edge filter is employed is employed in some DXA scanners to split the beam into high and low energies

c) Material the detector is made of

d) The calibration phantom

b) A K-edge filter is employed is employed in some DXA scanners to split the beam into high and low energies

Rare earth K-edge filters are used in DXA scanners that have a constant potential generator to split the beam into dual energies.

True or False

Dual-photon absorptiometry operates on the same basic principle as SPA with either a single isotope capable of emitting energy at two peaks or two isotopes that have different peak energies.

True

DPA can operate with a single isotope or two isotopes. Dual energies allowed the system to measure the BMD of bones without a water bath, including spine or proximal femur. However, the cost to maintain the unit, coupled with the loss of precision and accuracy as the isotope(s)decayed rendered DPA obsolete.

Radiogrammetry is the measurement of bones using skeletal radiography. Which site was most often used?

a) Proximal femur

b) Spine

c) Tibia

d) Metacarpals

d) Metacarpals

The most commonly used site for radiogrammetry is the metacarpals. This method is not used often today because it is a very tedious exam to perform.

Pencil-beam scanners use a ________________________ x-ray beam that moves in tandem with the detector.

a) Wide

b) Parallel

c) Collimated

d) Perpendicular

c) Collimated

Pencil beam scanners use a collimated or narrow X-ray beam. Scan times are slower that fan beam scanners and the radiation dose is slightly lower.

True or False

Internal calibration is used for system calibration in scanners with rare earth K-edge filters.

False

The answer is false. Scanners that employ K-edge filtering have external calibration systems.

True or False

Clinical usefulness is not impacted by method of dual-energy production.

True

Clinical usefulness is not impacted by method of dual-energy production. Both systems work equally well and provide useful DXA studies.

Despite slightly higher radiation dose to the patient, fan-beam (array) scanners offer the advantage of ______________________.

a) Fast scan times

b) High resolution images

c) Vertebral fracture assessment (VFA)

d) All the above

d) All the above

Fan-beam (array) scanners offer all the advantages listed. Fan-beam scanners are especially useful when VFA is desired because pencil beam scanners do not have the capability to perform VFA.

What advantages does QCT or Quantitative CT offer in bone density testing?

a) Volumetric measurement

b) Separates trabecular and cortical bone

c) Vertebral size does not cause error in reading

d) All the above

d) All the above

QCT separates trabecular from cortical bone, which is useful because certain bone disorders are found in trabecular bone. Volumetric measurement considers the entire vertebrae verse the aerial measurements of a DXA unit.

Radiographic absorptiometry is the practice of digitizing high resolution radiographs and running a computer analysis on the images. How many films are taken of the same site to be analyzed?

a) Four films

b) Two films

c) One film

d) None of the above

b) Two films

Two films are taken of the same site with different exposure factors. Both films are then digitized and analyzed.

What are the peak energies typically found in a DXA system?

a) Low energy (10KeV) and high energy (200KeV)

b) Low energy (100 KeV) and high energy (50 KeV)

c) Low energy (30-50KeV) and high energy (greater than 70KeV)

d) 55 KVP and 25 mAs

c) Low energy (30-50KeV) and high energy (greater than 70KeV)

The typical ranges found in DXA scanners are low energy (30-50KeV) and high energies (greater than 70 KeV). These energies best distinguish bone from soft tissue

True or False

Quantitative Ultrasound (QUS) can be used to measure spine and hip sites.

False

QUS can only be used on peripheral sites.

True or False

Fan-beam or array scanners have a broader, fan shaped beam. Scanning occurs line by line and scan times are shorter.

True

This statement is true. The beam is wider, scan times are usually under 1 minute and image resolution is higher.

Single-photon absorptiometry (SPA) is the predecessor of today's DXA machines. Which statement(s) are true?

a) First described in 1963

b) A radioisotope was used to generate the photon energy

c) The site being scanned must be of uniform thickness, achieved by submerging in a water bath

d) All the above

d) All the above

The the statements are true. The site scanned usually was the radius which was submerged in a water bath or tissue equivalent. This method was both precise and accurate, but technology has made it obsolete.

Densitometry was used in ________________ over 100 years ago.

a) CT scanning

b) Veterinarian medicine

c) Dental radiography

d) Plain radiography

c) Dental radiography

Densitometry was used in dental radiography over 100 years ago.

What is this radiograph image an example of?

[image]

a) a plain hand radiograph

b) Qualitative Morphometry

c) Peripheral DXA Scan

d) Radiographic Absorptiometry

d) Radiographic Absorptiometry

This image is illustrates radiographic absorptiometry. Note the aluminum wedge that serves as a measurement reference.

True or False

SPA and DPA are used currently in clinical medicine.

False

Neither of these systems are used in clinical medicine at this time. DXA technology has replaced them.