DXA SCANNING EXAM QUESTIONS AND
ANSWERS 100% VERIFIED.
what did DXA replace - ANSWERSDPA
DPA - ANSWERSrelied on gaodolinium - 153 radionuclide.
long scan time
BMD - ANSWERSbone mineral density
T - score between -1.0 and -2.5 = osteopaenia
T - score less than / equal to -2.5 = osteoporosis
Why do scans have to be done on the same scanner - ANSWERSthe densitometry
results obtained by different manufacturers scanners are not necessarily comparable.
fan beam densitometers - ANSWERShave an array of x-rays and detectors
wide angle fan beam: oriented transverse to the long axis of the body (hologic)
narrow angle fan beam: parallel to the long axis of the body (GE)
shorter scan acquisition times and higher image resolution
central methods - ANSWERSinclude DXA and quantitative CT allow measurement of
spine and proximal femur.
peripheral methods - ANSWERSincluding peripheral dual x-ray absorptiometry (pDXA)
and peripheral quantitative CT (pQCT) allow measurement of distal femur, tibia,
calcaneus,forearm or phalanges
why is DXA gold standard for measuring BMD? - ANSWERSmost widely studied
excellent reproducability
low radiation dose (1/10 of CXR)
current WHO diagnostic criteria for osteoporosis
Who criteria for osteoporosis / osteopaenia - ANSWERST - score greater than / equal to
-1.0 = normal
High - resolution ceramic digital detectors array - ANSWERSultra fast, high output, low
noise ceramic detectors
better bone mapping and images
High frequency dual energy x-ray source - ANSWERSsmaller and lighter than previous
generations
Dual energy beam - ANSWERSneeded to determine how much of the attenuation is
attributable to bone rather than soft tissue
ANSWERS 100% VERIFIED.
what did DXA replace - ANSWERSDPA
DPA - ANSWERSrelied on gaodolinium - 153 radionuclide.
long scan time
BMD - ANSWERSbone mineral density
T - score between -1.0 and -2.5 = osteopaenia
T - score less than / equal to -2.5 = osteoporosis
Why do scans have to be done on the same scanner - ANSWERSthe densitometry
results obtained by different manufacturers scanners are not necessarily comparable.
fan beam densitometers - ANSWERShave an array of x-rays and detectors
wide angle fan beam: oriented transverse to the long axis of the body (hologic)
narrow angle fan beam: parallel to the long axis of the body (GE)
shorter scan acquisition times and higher image resolution
central methods - ANSWERSinclude DXA and quantitative CT allow measurement of
spine and proximal femur.
peripheral methods - ANSWERSincluding peripheral dual x-ray absorptiometry (pDXA)
and peripheral quantitative CT (pQCT) allow measurement of distal femur, tibia,
calcaneus,forearm or phalanges
why is DXA gold standard for measuring BMD? - ANSWERSmost widely studied
excellent reproducability
low radiation dose (1/10 of CXR)
current WHO diagnostic criteria for osteoporosis
Who criteria for osteoporosis / osteopaenia - ANSWERST - score greater than / equal to
-1.0 = normal
High - resolution ceramic digital detectors array - ANSWERSultra fast, high output, low
noise ceramic detectors
better bone mapping and images
High frequency dual energy x-ray source - ANSWERSsmaller and lighter than previous
generations
Dual energy beam - ANSWERSneeded to determine how much of the attenuation is
attributable to bone rather than soft tissue
