DEXA
low bone mass (osteopenia) score
T score between -1.0 and -2.5
acute vertebral fractures are managed by
kyphoplasty
shielding is
built into the scanner
DEXA usually gives off msv of
1-5 mSv
operator console should be a distance of
3 feet from source
original scanners used
pencil-beam and a single detector
primary osteoporosis
post-menopausal or age related
normal
t-score above -1.0
osteoporosis
t-score of -2.5 or greater
Peak bone mass is reached between
the ages of 20-30
for the most accurate results
Patients should be scanned on the same machine, and positioned the same way as previous scans
severe osteoporosis
T - score of -2.5 or greater AND a history of fractures
T-score
determines fracture risk, diagnoses osteoporosis, and determines if therapy is needed.
Z-score
determines if the measured BMD is reasonable, and if further evaluation is warranted.
osteoporosis
disease of the bone characterized by low bone mass, structural deterioration of bone tissue, risk for fragility fractures, and occurs primarily in females.
Stability in bone mass requires
equal absorption/retention
falls and fractures with osteoporosis
fragility fractured occur with minimal trauma from a standing height or less
newer technology uses a
array beam (or fan-beam) with multi element detector. Reduces scan time, produces better image resolution, and allows for lateral thoracic and lumbar scanning.
osteoblasts
bone building
kyphoplasty definition
bone cement is injected into the vertebral body
osteoclasts
bone destroying
measures
bone mineral content (BMC) and bone mineral density (BMD).
used to access
bone strength, diagnose diseases associated with low bone density (especially osteoporosis), monitor therapy, and predict fracture risk.
secondary osteoporosis
caused by skeletal disorders
completed clinical requirements include
mandatory 50 lumbar and hip scans, patient prep and education, daily quality control procedures, and elective procedures.
accuracy
measurement of the true value of an object (calibration of equipment and preventative maintenence)
purpose and principle of DEXA
measures bone mineral density, establishes the diagnosis of osteoporosis, and assesses the response to osteoporosis therapy. It uses two different photon energies (soft tissue, bone) and detectors are used to separate and measure the low and high-energy photons (demonstrates attenuation difference between bone and soft tissue).
proximal femur (hip)
predictor of future femur fractures
purpose of skeleton is
support and protect vital organs, produce RBCs, and store minerals necessary for life.
precision
the ability of the system to reproduce the same results in repeat measurements of the same object.
DEXA technique
uses a subtraction technique
Decrease in bone mass starts in
women at the age of 50, and men at the age of 65
DEXA
Dual Energy X-Ray Absorptiometry
lumbar scans analyze
L-1 to L-5
prevention of osteoporosis
obtain daily amounts of calcium and vitamin D, engage in regular resistance and weight-bearing exercise, and avoid smoking and excessive alcohol
loss of bone mass occurs
when the bone remodeling process becomes uncoupled.
