DXA OPERATOR'S EXAM UPDATED ACTUAL QUESTIONS
AND CORRECT ANSWERS
Question:
1. What does DXA stand for?
Answer:
dual-energy x-ray absorptiometry
Question:
2. Advantages of DXA
Answer:
Gold standard of measures, low radiation dose, wide availability, ease of use, short scan time, high-res
images, good precision, stable calibration.
Question:
3. 3 major US DXA manufacturers
Answer:
GE Lunar Corp, Hologic Inc, Norland Swissray Corp.
Question:
4. How is BMD quantified?
Answer:
Subtraction technique-- soft tissue is eliminated to measure xray attenuation of bone alone. This is done
using 2 different xray photon energies (dual energy) and mathematically manipulating the signal to take
advantage of the differing attenuation properties of soft tissue and bone at the 2 energies.
Question:
5. How is density of isolated bone calculated?
Answer:
Denser, more mineralized bone attenuates (absorbs) more xrays.
Question:
6. What are DXA results computed off of?
Answer:
Proprietary software from xray attenuation (absorption) pattern striking the detector, not the scan image
Question:
7. ROI:
Answer:
Region of interest
Question:
8. Can you use DXA for diagnosis?
,Answer:
NO. DXA scans provide images only for the purpose of confirming correct positioning of the patient and
correct placement of the ROI's.
Question:
9. How does bone densitometry differ from diagnostic radiology?
Answer:
Good image quality, which can tolerate variability in technique, is not the ultimate goal. The goal is
accurate and precise quantitative measurement by the scanner software, which requires stable equipment
and careful, consistent work from the operator.
Question:
10. Osteoporosis
Answer:
Systemic skeletal disease characterized by low bone mass and microarchitectural deterioration of bone
tissue. As a result, the bones are at increased risk for fragility fractures.
Question:
11. How many Americans have osteoporosis (estimated)? What % of those are women?
Answer:
10 million with 80% being women
Question:
12. Osteopenia:
Answer:
Low bone mass, which puts patients at risk for developing osteoporosis in the future.
Question:
13. True or false: Patients with a normal rate of bone loss may still develop osteoporosis if their peak bone
mass is low.
Answer:
TRUE
Question:
14. What is the Bone Mass Measurement Act? (BMMA)
Answer:
BMMA authorizes Medicare coverage (to get a DXA) for these 5 categories:
-an estrogen-deficient women at clinical risk for osteoporosis
-a person w/ vertebral abnormalities
-a person receiving long-term glucocorticoid/steroid therapy
-someone w/ primary hyperparathyroidism
-someone being monitored to assess the response to (and efficacy of) an approved osteoporosis drug
therapy
Question:
15. Types of osteoporosis:
, Answer:
Primary: Type I, post-menopausal Type II (senile or age-related) Secondary (caused by other conditions
like hyperparathyroidism, gonadal insufficiency, rickets/osteomalacia in children, rheumatoid arthritis,
anorexia nervosa, gastrectomy, adult sprue/hypersensitivity to gluten, multiple myeloma, use of
corticosteroids, heparin, or anticonvulsants or excessive thyroid hormone treatment.
Question:
16. When does primary type 1 osteoporosis occur?
Answer:
When bone resorption exceed bone formation because of decreased estrogen levels in women
Question:
17. When does primary Type II osteoporosis occur?
Answer:
In men and women when they get old, they have a decreased ability to build bone. They are really just
(trying to) maintaining what they had.
Question:
18. Types of prescription meds that arrest bone loss and may increase bone mass:
Answer:
estrogen or hormone replacement therapy, biphosphonates, selective estrogen receptor modulators
(SERMS), salmon calcitonin, and parathyroid hormone, and RANK ligand.
Question:
19. Controllable risk factors of osteoporosis:
Answer:
Calcium intake, vitamin D intake, smoking, alcohol, sedentary lifestyle
Question:
20. Uncontrollable risk factors of osteoporosis:
Answer:
Age, gender (WOMEN), family history, previous fracture, ethnicity (WHITE AND ASIAN), small bones
and body weight under 127, menopause, estrogen deficiency, excessive exercise, menstrual history that
includes cessation of menses before menopause bc of eating disorders, some drugs: long-term
glucocorticoid therapy, rheumatoid arthritis, primary/secondary hypogonadism in men
Question:
21. What is mathematically eliminated?
Answer:
Soft tissue attenuation is mathematically eliminated. The remaining attenuation is because of the amount
of bone present.
Question:
22. Cortical bone:
AND CORRECT ANSWERS
Question:
1. What does DXA stand for?
Answer:
dual-energy x-ray absorptiometry
Question:
2. Advantages of DXA
Answer:
Gold standard of measures, low radiation dose, wide availability, ease of use, short scan time, high-res
images, good precision, stable calibration.
Question:
3. 3 major US DXA manufacturers
Answer:
GE Lunar Corp, Hologic Inc, Norland Swissray Corp.
Question:
4. How is BMD quantified?
Answer:
Subtraction technique-- soft tissue is eliminated to measure xray attenuation of bone alone. This is done
using 2 different xray photon energies (dual energy) and mathematically manipulating the signal to take
advantage of the differing attenuation properties of soft tissue and bone at the 2 energies.
Question:
5. How is density of isolated bone calculated?
Answer:
Denser, more mineralized bone attenuates (absorbs) more xrays.
Question:
6. What are DXA results computed off of?
Answer:
Proprietary software from xray attenuation (absorption) pattern striking the detector, not the scan image
Question:
7. ROI:
Answer:
Region of interest
Question:
8. Can you use DXA for diagnosis?
,Answer:
NO. DXA scans provide images only for the purpose of confirming correct positioning of the patient and
correct placement of the ROI's.
Question:
9. How does bone densitometry differ from diagnostic radiology?
Answer:
Good image quality, which can tolerate variability in technique, is not the ultimate goal. The goal is
accurate and precise quantitative measurement by the scanner software, which requires stable equipment
and careful, consistent work from the operator.
Question:
10. Osteoporosis
Answer:
Systemic skeletal disease characterized by low bone mass and microarchitectural deterioration of bone
tissue. As a result, the bones are at increased risk for fragility fractures.
Question:
11. How many Americans have osteoporosis (estimated)? What % of those are women?
Answer:
10 million with 80% being women
Question:
12. Osteopenia:
Answer:
Low bone mass, which puts patients at risk for developing osteoporosis in the future.
Question:
13. True or false: Patients with a normal rate of bone loss may still develop osteoporosis if their peak bone
mass is low.
Answer:
TRUE
Question:
14. What is the Bone Mass Measurement Act? (BMMA)
Answer:
BMMA authorizes Medicare coverage (to get a DXA) for these 5 categories:
-an estrogen-deficient women at clinical risk for osteoporosis
-a person w/ vertebral abnormalities
-a person receiving long-term glucocorticoid/steroid therapy
-someone w/ primary hyperparathyroidism
-someone being monitored to assess the response to (and efficacy of) an approved osteoporosis drug
therapy
Question:
15. Types of osteoporosis:
, Answer:
Primary: Type I, post-menopausal Type II (senile or age-related) Secondary (caused by other conditions
like hyperparathyroidism, gonadal insufficiency, rickets/osteomalacia in children, rheumatoid arthritis,
anorexia nervosa, gastrectomy, adult sprue/hypersensitivity to gluten, multiple myeloma, use of
corticosteroids, heparin, or anticonvulsants or excessive thyroid hormone treatment.
Question:
16. When does primary type 1 osteoporosis occur?
Answer:
When bone resorption exceed bone formation because of decreased estrogen levels in women
Question:
17. When does primary Type II osteoporosis occur?
Answer:
In men and women when they get old, they have a decreased ability to build bone. They are really just
(trying to) maintaining what they had.
Question:
18. Types of prescription meds that arrest bone loss and may increase bone mass:
Answer:
estrogen or hormone replacement therapy, biphosphonates, selective estrogen receptor modulators
(SERMS), salmon calcitonin, and parathyroid hormone, and RANK ligand.
Question:
19. Controllable risk factors of osteoporosis:
Answer:
Calcium intake, vitamin D intake, smoking, alcohol, sedentary lifestyle
Question:
20. Uncontrollable risk factors of osteoporosis:
Answer:
Age, gender (WOMEN), family history, previous fracture, ethnicity (WHITE AND ASIAN), small bones
and body weight under 127, menopause, estrogen deficiency, excessive exercise, menstrual history that
includes cessation of menses before menopause bc of eating disorders, some drugs: long-term
glucocorticoid therapy, rheumatoid arthritis, primary/secondary hypogonadism in men
Question:
21. What is mathematically eliminated?
Answer:
Soft tissue attenuation is mathematically eliminated. The remaining attenuation is because of the amount
of bone present.
Question:
22. Cortical bone:
