Post on 14-Jan-2016
description
BONE DENSITOMETRY
BONE DENSITOMETRYTHE ART AND SCIENCE OF MEASURING THE BONE MINERAL CONTENT AND DENSITY OF SPECIFIC SKELETAL SITES OR THE WHOLE BODY.
THE MOST VERSATILE AND WIDELY USED TECHNIQUEDUAL X-RAY ABSORPTIOMETRY
DXA
DXA
DXA ADVANTAGESLOW RADIATION DOSEWIDE AVAILABILITYEASE OF USESHORT SCAN TIMEHIGH RESOLUTION IMAGESGOOD PRECISIONSTABLE CALIBRATION
DXAIS A SUBTRACTION TECHNIQUE- SOFT TISSUE STRUCTURES ARE ELIMINATED. X-RAY ATTENUATION OF THE BONE IS MEASURED. BONE MINERAL DENSITY IS CALCULATED (BMD)
BMD
DXASCANS PROVIDE IMAGES FOR THE PURPOSE OF CONFIRMING THE CORRECT POSITIONING OF THE PATIENT AND CORRECT PLACEMENT OF ROI ( REGION OF INTEREST)
IMAGES ARE NOT USED FOR DIAGNOSIS!!
THE BONE DENSITY RESULTS ARE COMPUTED AND PRINTED BY SOFTWARE
DXA COMPUTATIONAL SOFTWARE
HISTORYOSTEOPOROSIS UNDETECTED AND OVERLOOKED UNTIL 1920s.THE FIRST PUBLICATION ABOUT BONE MASS APPEARED IN 1930s.RA- RADIOGRAPHIC ABSORPTIOMETRY- X-RAY TAKEN AND COMPARED TO A STANDARD RADIOGRAPH RADIOGAMMETRY INTRODUCED IN THE 1960s IN RESPONSE TO THE MEASUREMENT OF A BONE LOSS IN ASTRONAUTS.
IN 1970 CT WAS USED THROUGH THE SPECALIZED SOFTWARE. QUANTITATIVE CT.1970s AND 1980s BROUGHT THE FIRST DEDICATED SCANNERS. FIRST SPA THEN DPA. USED RADIOISOTOPE AS A SOURCE OF RADIATION.FIRST COMMERCIAL DXA SCANNER INTRODUCED IN 1987 FIRST USED RADIOISOTOPE AS THE X-RAY SOURCE THEN REPLACED BY THE X-RAY TUBE.
DXA OF THE HIP AND SPINE IS THE MOST ACCEPTED METHOD FOR MEASURING BONE DENSITY
CT BONE DENSITOMETRY
SPA SCANNER
HIP AND SPINE DXA
BONE BIOLOGY
SKELETON PURPOSESBODY SUPPORT
RED BLOOD CELLS MANUFACTURING
MINERAL STORAGE
BONE TYPESCORTICAL
TRABECULAR- ( CANCELLOUS)
BONE CROSS-SECTION
CORTICAL BONE ACCOUNTS FOR 80% OF SKELETAL MASS
IT SUPPORTS WEIGHT
TRABECULAR BONE IS THE DELICATE LATTICE WITHIN THE BONE THAT ADDS STRENGTH
SPECIFIC BONE40% ORGANIC MATTER
60% BONE MINERALDXA MEASURES THE DENSITY OF BONE MINERAL
BONE IS CONSTANTLY GOING HROUGH THE REMODELING PROCESS
PEAK BONE MASS AT THE AGE OF 30-35
DECREASING BONE MASS STARTING AT THE AGE OF 50
DECREASE IN BONE MASS PRONOUNCED IN WOMEN AT MENOPAUSE
LOSS OF BONE PRESERVING ESTROGEN!
OSTEOPOROSISOsteoporosis, or "thin" bones, is a disease that gradually weakens bones, making them more fragile and likely to break. It is not a form of arthritis. Osteoporosis leads to an increase in certain types of fractures (broken bones), such as hip fractures, wrist fractures, and compression fractures of the spinal vertebrae (back bones)
RISK FACTORS FOR OSTEOPOROSIS IN WOMENMENOPAUSESMALL BONE FRAMEFAMILY HISTORYADVANCED AGELOW CALCIUM DIETINACTIVE LIFESTYLECIGARETTE SMOKINGGI MALABSORPTION PROBLEMCERTAIN MEDICATION USE- CORTICOSTEROIDS
MINERAL CONTENT CALCULATION IN BONE DENSITOMETRYBMC = BMD X AREA
DXA SYSTEMSPENCIL BEAM
FAN BEAM
PENCIL BEAM SCANNER
FAN BEAM SCANNER