BONE DENSITOMETRY

THE 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 TECHNIQUE DUAL X-RAY ABSORPTIOMETRY DXA

DXA ADVANTAGES LOW RADIATION DOSE WIDE AVAILABILITY EASE OF USE SHORT SCAN TIME HIGH RESOLUTION IMAGES GOOD PRECISION STABLE CALIBRATION

DXA IS A SUBTRACTION TECHNIQUE- SOFT TISSUE STRUCTURES ARE ELIMINATED. X-RAY ATTENUATION OF THE BONE IS MEASURED. BONE MINERAL DENSITY IS CALCULATED (BMD)

BMD

DXA SCANS 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

HISTORY OSTEOPOROSIS 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 PURPOSES BODY SUPPORT RED BLOOD CELLS MANUFACTURING MINERAL STORAGE

BONE TYPES CORTICAL 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 BONE 40% ORGANIC MATTER 60% BONE MINERAL DXA 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!

OSTEOPOROSIS Osteoporosis, 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 WOMEN MENOPAUSE SMALL BONE FRAME FAMILY HISTORY ADVANCED AGE LOW CALCIUM DIET INACTIVE LIFESTYLE CIGARETTE SMOKING GI MALABSORPTION PROBLEM CERTAIN MEDICATION USE- CORTICOSTEROIDS

MINERAL CONTENT CALCULATION IN BONE DENSITOMETRY BMC = BMD X AREA

DXA SYSTEMS PENCIL BEAM FAN BEAM

PENCIL BEAM SCANNER

FAN BEAM SCANNER