Dual-energy X-ray absorptiometry

DEXAdual energy X-ray absorptiometrybone densitometryDXAabsorptiometry, photonDEXA scannerDual-Energy X-ray Absorptiometry (DEXA)bone density gaugebone density scanDEXA Bone Densitometry
Dual-energy X-ray absorptiometry (DXA, previously DEXA ) is a means of measuring bone mineral density (BMD) using spectral imaging.wikipedia
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Osteoporosis

bone lossosteoporoticpostmenopausal osteoporosis
The DXA scan is typically used to diagnose and follow osteoporosis, as contrasted to the nuclear bone scan, which is sensitive to certain metabolic diseases of bones in which bones are attempting to heal from infections, fractures, or tumors.
This is typically measured by dual-energy X-ray absorptiometry.

United States Preventive Services Task Force

U.S. Preventive Services Task ForceUS Preventive Services Task ForceUSPSTF
The U.S. Preventive Services Task Force recommends that women over the age of 65 should get a DXA scan.

Dual X-ray absorptiometry and laser

Dual X-ray Absorptiometry and Laser (DXL)
The combination of dual X-ray absorptiometry and laser uses the laser to measure the thickness of the region scanned, allowing for varying proportions of lean soft tissue and adipose tissue within the soft tissue to be controlled for and improving the accuracy.
Dual X-ray absorptiometry and laser technique (DXL) in the area of bone density studies for osteoporosis assessment is an improvement to the DXA Technique, adding an exact laser measurement of the thickness of the region scanned.

Bone

cortical bonebone tissuecancellous bone
Two X-ray beams, with different energy levels, are aimed at the patient's bones.
This density is measured using dual energy X-ray absorptiometry (DEXA), with the term "established osteoporosis" including the presence of a fragility fracture.

Bone density

bone mineral densitybone massBone Densitometry
Dual-energy X-ray absorptiometry (DXA, previously DEXA ) is a means of measuring bone mineral density (BMD) using spectral imaging. When soft tissue absorption is subtracted out, the bone mineral density (BMD) can be determined from the absorption of each beam by bone.

Osteopenia

Diminished bone densityOsteopaeniaReduced bone mass
This would lead to an over-diagnosis of osteopenia for children.
Scans of bones anywhere in the body can be done with X-rays, known as DEXA (dual X-ray absorptiometry).

Quantitative computed tomography

peripheral quantitative CTpQCTquantitative computer tomographic
Other imaging technologies such as quantitative computed tomography (QCT) are capable of measuring the bone's volume, and are, therefore, not susceptible to the confounding effect of bone-size in the way that DXA results are susceptible.
QCT enables spine BMD measurements on patients with scoliosis, which cannot usually be measured using Dual-energy X-ray absorptiometry (DXA).

Adipose tissue

adiposebody fatfat
The combination of dual X-ray absorptiometry and laser uses the laser to measure the thickness of the region scanned, allowing for varying proportions of lean soft tissue and adipose tissue within the soft tissue to be controlled for and improving the accuracy.
Before bioelectrical impedance analysis machines were developed, there were many different ways in analyzing body composition such as skin fold methods using calipers, underwater weighing, whole body air displacement plethysmography (ADP) and DXA.

Rickets

rachitisrachiticantirachitic
Some clinics may routinely carry out DXA scans on pediatric patients with conditions such as nutritional rickets, lupus, and Turner syndrome.

Body composition

fat free massbody composition monitorsfat free mass (FFM)
DXA scans can also be used to measure total body composition and fat content with a high degree of accuracy comparable to hydrostatic weighing with a few important caveats.
Body composition measurement with dual energy X-ray absorptiometry (DEXA) is used increasingly for a variety of clinical and research applications.

Spectral imaging (radiography)

spectral imagingDual-energy'' radiographyspectral
Dual-energy X-ray absorptiometry (DXA, previously DEXA ) is a means of measuring bone mineral density (BMD) using spectral imaging.

X-ray

X-raysX raysoft X-ray
Two X-ray beams, with different energy levels, are aimed at the patient's bones.

Energy level

energy levelsenergy stateenergy states
Two X-ray beams, with different energy levels, are aimed at the patient's bones.

Soft tissue

soft tissuessoft-tissueanimal tissue
When soft tissue absorption is subtracted out, the bone mineral density (BMD) can be determined from the absorption of each beam by bone.

Bone scintigraphy

bone scanbone scans3-phase bone scan
The DXA scan is typically used to diagnose and follow osteoporosis, as contrasted to the nuclear bone scan, which is sensitive to certain metabolic diseases of bones in which bones are attempting to heal from infections, fractures, or tumors.

Attenuation

attenuateattenuatedattenuating
Soft tissue and bone have different attenuation coefficients to X-rays.

Cerium

CeCe IV
One type of DXA scanner uses a cerium filter with a tube voltage of 80 kV, resulting in effective photon energies of about 40 and 70 keV.

X-ray tube

X-ray tubestube voltageCoolidge tube
One type of DXA scanner uses a cerium filter with a tube voltage of 80 kV, resulting in effective photon energies of about 40 and 70 keV.

Volt

VkVvolts
One type of DXA scanner uses a cerium filter with a tube voltage of 80 kV, resulting in effective photon energies of about 40 and 70 keV.

Electronvolt

MeVeVkeV
One type of DXA scanner uses a cerium filter with a tube voltage of 80 kV, resulting in effective photon energies of about 40 and 70 keV.

Samarium

SmSm 2 153 Sm
There is also a DXA scanner type using a samarium filter with a tube voltage of 100 kV, resulting in effective energies of 47 and 80 keV.

World Health Organization

WHOWorld Health OrganisationWorld Health Organization (WHO)
A person's risk can be measured using the World Health Organization's FRAX calculator, which includes many different clinical risk factors including prior fragility fracture, use of glucocorticoids, heavy smoking, excess alcohol intake, rheumatoid arthritis, history of parental hip fracture, chronic renal and liver disease, chronic respiratory disease, long-term use of phenobarbital or phenytoin, celiac disease, inflammatory bowel disease, and other risks.

FRAX

A person's risk can be measured using the World Health Organization's FRAX calculator, which includes many different clinical risk factors including prior fragility fracture, use of glucocorticoids, heavy smoking, excess alcohol intake, rheumatoid arthritis, history of parental hip fracture, chronic renal and liver disease, chronic respiratory disease, long-term use of phenobarbital or phenytoin, celiac disease, inflammatory bowel disease, and other risks.

Glucocorticoid

glucocorticoidssteroidssteroid
A person's risk can be measured using the World Health Organization's FRAX calculator, which includes many different clinical risk factors including prior fragility fracture, use of glucocorticoids, heavy smoking, excess alcohol intake, rheumatoid arthritis, history of parental hip fracture, chronic renal and liver disease, chronic respiratory disease, long-term use of phenobarbital or phenytoin, celiac disease, inflammatory bowel disease, and other risks.

Standard score

normalizednormalisedz-score
To avoid an overestimation of bone mineral deficits, BMD scores are commonly compared to reference data for the same gender and age (by calculating a Z-score).