Panel Disdussion

3rd International Congress 3rd International of Nuclear Congress Medicine of Nuclear & 15th Medicine Iranian Annual & 15th Iranian Congress Annual of
Nuclear Congress Medicine of Nuclear Medicine
Shahid Beheshti Shahid Beheshti University University of Medical Sciences of Medical 19-21 Sciences May 201119-21 May 2011
Is parentage error of bone Density determined by DEXA
technique influenced by density?
Azadeh Emami 1 , Hossein Ghadiri 1 , Mohammad Reza Ay 1 , Shahram
Akhlaghpour 2 , Pardis Ghafarian 1 , Sima Taghizadeh 1
1 Research Center for Science and Technology in Medicine
2 Departments of Interventional Radiology
Introduction: accurate performance assessment of bone mineral
densitometry is crucial due to the fact a high level of exact estimation
of bone situation is needed for correct diagnosis of patient with bone
disease. Variation of parameters like percentage error which highly
affect the densitometry results may induce some level of uncertainty
in diagnosis procedure. So, determination of this variation and
designing an algorithm for correction is necessary to assure
examiners about measurement results.
Method: In this study several phantoms consisting of soft tissueand
bone-equivalent material was devised to accurately test bone
densitometry systems. A Plexiglas cylindrical phantom was designed
and constructed as a spine phantom to assess different bone
densities. This phantom consists of two male-female separated parts
which each part consists of two cylindrical shape vertebras .Four
inserts in spine phantom with precisely wide range of K2HPO4
simulate trabecular bone, and provide the basis for the accurately
check of bone densitometry systems. Torso phantom is made up of
polyethylene and designed in such a way that imitates the torso
contour of human body and a hole in the low-middle part of it for
inserting the spine phantom in.
Results: The designed phantoms were used for performance
assessment of Bone Mineral Measurement DEXA Technique. Data
represents percentage error variation in DEXA in different densities.
It is clear that there is a declining trend of percentage error in
measured density versus true density values in DEXA technique.
There is a linear regression equation plot between measured density
and percentage error. The correlation coefficient and slope resulting
from the regression analysis of the measured density versus
percentage error by DEXA is calculated (slope:-0.32, intercept: 0.44).
Conclusion: As it is shown, sensitivity varies by mineral density of
spine results in an uncertainty in measurement procedure. The need
for standardization and evaluation in bone mineral measurements has
been recognized. A spine phantom was designed and produced to
evaluate the percentage error variation in bone densitometry
measurements. These assessments cover wide range of mineral
density that simulated to cover different stages of bone situation. In
this research it is demonstrated that the percentage error can be
affected by spine density that may cause uncertain results.
Keywords: DEXA, BMD, Phantom, Percentage error
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