DXA REVIEW QUESTIONS WITH 100%
VERIFIED ANSWERS.
Which type of cell is chiefly responsible for bone reabsorption in the remodeling cycle? -
ANSWERSOsteoclasts
How much bone loss must occur before it can be seen on a plain radiograph? -
ANSWERS30-50%
Describe how osteoporosis is defined by the WHO. - ANSWERSdecreased bone mass
that increases your susceptibility to fracture
What regions are analyzed for BMD values when scanning the hip? - ANSWERSFemur-
intertrochanertic, greater trocanter
Identify the risk factors associated with osteoporosis. - ANSWERSsex, age, family
history, body frame size
Explain the types of collimation used in DXA instrumentation. - ANSWERSPencil beam:
single detector, 5-7 min scan time, good resolution and reproducibility
Fan (array) beam: multi element detector, less than 1 min scan time, less resolution and
reproducibility
What are the two most commonly used sites in DXA when measuring a patient's BMD?
- ANSWERSLumbar spine and hip
Optimum site when clincially monitoring therapy? - ANSWERSSpine L1-L4
List the two methods used to obtain the two energy x-ray spectra required in DXA. -
ANSWERSk-edge filtered: Uses primary beam of ≤ 50 keV through rare earth filters
Energy switching system: Uses synchronous energy switching between 100 and 140
kVp
Which region is the first site of choice when scanning a patient with
hyperparathyroidism? - ANSWERSNon dominant forearm
VERIFIED ANSWERS.
Which type of cell is chiefly responsible for bone reabsorption in the remodeling cycle? -
ANSWERSOsteoclasts
How much bone loss must occur before it can be seen on a plain radiograph? -
ANSWERS30-50%
Describe how osteoporosis is defined by the WHO. - ANSWERSdecreased bone mass
that increases your susceptibility to fracture
What regions are analyzed for BMD values when scanning the hip? - ANSWERSFemur-
intertrochanertic, greater trocanter
Identify the risk factors associated with osteoporosis. - ANSWERSsex, age, family
history, body frame size
Explain the types of collimation used in DXA instrumentation. - ANSWERSPencil beam:
single detector, 5-7 min scan time, good resolution and reproducibility
Fan (array) beam: multi element detector, less than 1 min scan time, less resolution and
reproducibility
What are the two most commonly used sites in DXA when measuring a patient's BMD?
- ANSWERSLumbar spine and hip
Optimum site when clincially monitoring therapy? - ANSWERSSpine L1-L4
List the two methods used to obtain the two energy x-ray spectra required in DXA. -
ANSWERSk-edge filtered: Uses primary beam of ≤ 50 keV through rare earth filters
Energy switching system: Uses synchronous energy switching between 100 and 140
kVp
Which region is the first site of choice when scanning a patient with
hyperparathyroidism? - ANSWERSNon dominant forearm
