DXA Board Exam | Study Guide & Practice Questions
According to the WHO criteria, what is the diagnosis of osteoporosis based on the measurement of bone
density? - (answer)2.5 SD or more below the young adult peak bone density
What is the gold standard technique for measuring bone density? - (answer)DXA
Cancellous bone is also know as? - (answer)Trabecular Bone
What is the anatomical landmark on the proximal femur that gives the best visual indication of the
degree of rotation of the proximal femur? - (answer)Lesser Trochanter
Which lumbar vertebra is described as having a characteristic shape of an X or and H on a DXA PA spine
scan? - (answer)L4
Is Forteo a bisphosphonate? - (answer)NO
Quantitative Computated Tomography (QCT) - (answer)-measurements are volumetric
-trabecular bone can be isolated from cortical bone
-accuracy may be affected by marrow fat
Peripheral BMD measurements are advocated for _____________? - (answer)Screening
What is the most important clinical consequence of osteoporosis? - (answer)Fracture
What is the name of the tool that integrates clinical information in a quantitative manner to predict a
10-year probability of major osteoporotic fracture for both men and women? - (answer)FRAX
What is the major source of precision error in clinical practice? - (answer)Technologist
,DXA Board Exam | Study Guide & Practice Questions
What is the percentage of trabecular bone in the skeleton? - (answer)20 %
The forearm is not used to monitor the effects of therapy for osteoporosis because....... - (answer)rate of
change in BMD is too slow
What site is mostly composed of cortical bone? - (answer)Proximal forearm
What are the advantages of QUS over x-ray methodologies for BMD measurement? - (answer)-
ultrasound is comparatively inexpensive
-patients are not subjected to ionizing radiation
-ultrasound exams are quick to perform
What is the name of the isotope that was used in SPA? - (answer)Iodine-125
What is the texture index that evaluates the pixel gray-level variations in lumber spine DXA images? -
(answer)TBS (Trabecular Bone Score)
When does type 2 primary osteoporosis generally occur? - (answer)after age 70
What technique used images of the hand and an aluminum wedge? - (answer)RA (Radiograhic
Absorptiometry)
New bone is formed by the ___________? - (answer)osteoblasts
Cancellous bone is also known as _______________? - (answer)Trabecular bone
,DXA Board Exam | Study Guide & Practice Questions
How would you start labeling the vertebral bodies on a PA lumbar scan? - (answer)Start at L4 and
count/label up
With changes in rotation of the femoral neck, what happens? - (answer)Increases the BMD
If daily QC fails, what should be your first step of action? - (answer)-repeat the scan
-if scan fails again, then call for help
Although the technology is similar with all of the DXA units, the BMD results are different because..........
- (answer)-different calibration standards
-algorithms to calculate BMD
-differences in the ROI
-different databases
The primary mechanism of action of antiresorptive therapies is the direct interaction with the
__________________ - (answer)osteoclasts
Which site is preferred for determination of fracture prediction? - (answer)proximal femur
What is one disease not associated with low BMD? - (answer)osteopetrosis
DXA results may be influenced by......... - (answer)-body thickness
-degenerative changes
, DXA Board Exam | Study Guide & Practice Questions
-fractures
-scan mode
A great forearm scan should include....... - (answer)-forearm centered
-forearm straight
-free of artifacts
Phantoms that mimic the shape and size of a skeletal region are called
______________________________. - (answer)anthromomorphic phantoms
What is the formula used to calculate BMD? - (answer)BMD = BMC/Area
How often should you perform the QA on the DXA unit? - (answer)everyday you scan
Radiogammetry is the measurement of bones using skeletal x-rays/radiographs. Which site was often
used? - (answer)metacarpals
With voltage switching units, what type of calibration is used? - (answer)continuous internal calibration-
-wheel or drum
For low energies, the most common process of absorption is the ________________________ effect. -
(answer)photoelectric
What are some comparisons to the amount of effective dose given during a central DXA scan? -
(answer)-less than a day of background radiation
-less than a round trip from Boston to LA
According to the WHO criteria, what is the diagnosis of osteoporosis based on the measurement of bone
density? - (answer)2.5 SD or more below the young adult peak bone density
What is the gold standard technique for measuring bone density? - (answer)DXA
Cancellous bone is also know as? - (answer)Trabecular Bone
What is the anatomical landmark on the proximal femur that gives the best visual indication of the
degree of rotation of the proximal femur? - (answer)Lesser Trochanter
Which lumbar vertebra is described as having a characteristic shape of an X or and H on a DXA PA spine
scan? - (answer)L4
Is Forteo a bisphosphonate? - (answer)NO
Quantitative Computated Tomography (QCT) - (answer)-measurements are volumetric
-trabecular bone can be isolated from cortical bone
-accuracy may be affected by marrow fat
Peripheral BMD measurements are advocated for _____________? - (answer)Screening
What is the most important clinical consequence of osteoporosis? - (answer)Fracture
What is the name of the tool that integrates clinical information in a quantitative manner to predict a
10-year probability of major osteoporotic fracture for both men and women? - (answer)FRAX
What is the major source of precision error in clinical practice? - (answer)Technologist
,DXA Board Exam | Study Guide & Practice Questions
What is the percentage of trabecular bone in the skeleton? - (answer)20 %
The forearm is not used to monitor the effects of therapy for osteoporosis because....... - (answer)rate of
change in BMD is too slow
What site is mostly composed of cortical bone? - (answer)Proximal forearm
What are the advantages of QUS over x-ray methodologies for BMD measurement? - (answer)-
ultrasound is comparatively inexpensive
-patients are not subjected to ionizing radiation
-ultrasound exams are quick to perform
What is the name of the isotope that was used in SPA? - (answer)Iodine-125
What is the texture index that evaluates the pixel gray-level variations in lumber spine DXA images? -
(answer)TBS (Trabecular Bone Score)
When does type 2 primary osteoporosis generally occur? - (answer)after age 70
What technique used images of the hand and an aluminum wedge? - (answer)RA (Radiograhic
Absorptiometry)
New bone is formed by the ___________? - (answer)osteoblasts
Cancellous bone is also known as _______________? - (answer)Trabecular bone
,DXA Board Exam | Study Guide & Practice Questions
How would you start labeling the vertebral bodies on a PA lumbar scan? - (answer)Start at L4 and
count/label up
With changes in rotation of the femoral neck, what happens? - (answer)Increases the BMD
If daily QC fails, what should be your first step of action? - (answer)-repeat the scan
-if scan fails again, then call for help
Although the technology is similar with all of the DXA units, the BMD results are different because..........
- (answer)-different calibration standards
-algorithms to calculate BMD
-differences in the ROI
-different databases
The primary mechanism of action of antiresorptive therapies is the direct interaction with the
__________________ - (answer)osteoclasts
Which site is preferred for determination of fracture prediction? - (answer)proximal femur
What is one disease not associated with low BMD? - (answer)osteopetrosis
DXA results may be influenced by......... - (answer)-body thickness
-degenerative changes
, DXA Board Exam | Study Guide & Practice Questions
-fractures
-scan mode
A great forearm scan should include....... - (answer)-forearm centered
-forearm straight
-free of artifacts
Phantoms that mimic the shape and size of a skeletal region are called
______________________________. - (answer)anthromomorphic phantoms
What is the formula used to calculate BMD? - (answer)BMD = BMC/Area
How often should you perform the QA on the DXA unit? - (answer)everyday you scan
Radiogammetry is the measurement of bones using skeletal x-rays/radiographs. Which site was often
used? - (answer)metacarpals
With voltage switching units, what type of calibration is used? - (answer)continuous internal calibration-
-wheel or drum
For low energies, the most common process of absorption is the ________________________ effect. -
(answer)photoelectric
What are some comparisons to the amount of effective dose given during a central DXA scan? -
(answer)-less than a day of background radiation
-less than a round trip from Boston to LA
