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1. DUAL ENERGY X-RAY
ABSORPTIOMETRY

2. • •DUAL ENERGY X-RAY ABSORPTION (DEXA) is a most effective technique used to measure Bone
Mineral Density (BMD).
• . It measures the density or thickness of bones and amount of calcium in specific area of bone.
• •Average bone mineral density =BMC/W.
• Where, BMC = bone mineral content=g/cm.
• W = width at the scanned line.
• The more the mineral is bone measured, the less greater is the bone density or bone mass.
INTRODUCTION

3. VARIOUS WAYSTO MEASURE BM
 DUAL ENERGY X-RAY ABSORPTION (DEXA).
 PERIPHERAL DUAL ENERGY X-RAY ABSORPTION (P-DEXA).
 DUAL PHOTON DEXA.
 QUANTATIVE COMPUTER TOMOGRAPHY(QCT) .
 QUANTATIVE ULTRASOUND.

4. WHO SHOULD UNDER GO
Menopausal women, all women above 65 age or older and males over 70 age.
 Long term steroids, hormonal theraphy, Vit D, Calcium, Low estrogen level.
Lumphangiomatosis and low body weight.
Kyphosis.
Previous history of fracture.
Nutritional deficiency- rickets, lupus, Turner syndrome, rheumatoid arthritis.

5. EQUIPMENT
 A C-arm with x-ray source allowing for variable photon
energy levels
 Collimator
 .Detector
 Associated computer software

6. WORKING PRINCIPAL
 Photons are produced from low energy source.
 2 X-ray beams with different energy peaks pass through the body.
 One peak absorbs by the soft tissue and other by the bone.
 Creates a 2D image.
 Soft tissue is subtracted from the total area, giving the bone mineral
density.
 These measurements are then measured with the normal ranges
matched for chronological age with the help of T-score and Z-Score.

7. T-SCORE
• T-Score shows the amount of bone that is compared with a
young adult of the same gender with peak bone mass.The T-
score is mainly to determine the risk of developing fracture.

9. Z-SCORE
OZ-Score shows the amount of bone,compared with other people in same age group of the
same size, height and gender. Z score mainly to determine risk of having afracture.
✓A low Z-score below -2.0 is awarning sign of low bone mass than expected people of same
age of 30-year-old man/woman.
✓Z score = T-score-Reference T-Score.

11. CON TRAIN DICATION
 Bilateral hip replacement.
 Metal implants in the area.
 Pregnancy.
 Weight about (120-130)kg.
 Recent contrast studies.

13. PROCEDURE FOR SPINE

14. PROCEDURE FOR HIP

15. BEN EFITS
 Quick and noninvasive procedure.
 No anaesthesia required.
 Accurately measures the fracture risk.
 Less radiation exposure almost 0.001mSv.

16. PREVEN TION
 To prevent low bone density it is adviced to intake sufficient
calcium and vitamin.
 Regular excersise.

17. ADVANTAGES
• Suitable for most athletes
• Fast (~5 min for fanbeam up to ~1
• for some pencil beam)
• Able to provide regional body composition
• Low radiation dose (~0.5 µSv) and safe for sequential measurements
•Non-intrusive

18. DISADVANTAGES
•Expensive equipment
•Not portable
•Scanning bed is smaller than typical physique of many larger athletes
•Trained technician required
•Manufacturers’ body composition estimation algorithms are not developed on
athletes
•Unable to directly compare results

19. CONCLUSIONS
■Bone mineral density measurements are affected by the
apparent change in projected cross-sectional area caused by
axial rotations of the femur and by the positioning of the
ROI during scananalysis

20. DOUBTS..???

21. THANK YOU…