New Horizons for Hydroxyapatite Supported by DXA Assessment-A Preliminary Study

Abstract

Dual Energy X-ray Absorptiometry (DXA) is a tool that allows the assessment of bone density. It was first presented by Cameron and Sorenson in 1963 and was approved by the Food and Drug Administration. Misplacing the femoral neck box, placing a trochanteric line below the midland and improper placement of boundary lines are the most common errors made during a DXA diagnostic test made by auto analysis. Hydroxyapatite is the most important inorganic component of teeth and bone tissue. It is estimated to constitute up to 70% of human bone weight and up to 50% of its volume. Calcium phosphate comes in many forms; however, studies have shown that only tricalcium phosphate and hydroxyapatite have the characteristics that allow their use as bone-substituted materials. The purpose of this study is aimed at analyzing the results of hip densitometry and hydorxyapatite distribution in order to better assess the structure and mineral density of the femoral neck. However, a detailed analysis of the individual density curves shows some qualitative differences that may be important in assessing bone strength in the area under study. To draw more specific conclusions on the therapy applied for individual patients, we need to determine the correct orientation of the bone from the resulting density and document the trends in the density distribution change. The average results presented with the DXA method are insufficient.

Keywords: DXA; density; hydroxyapatite.

Figure 1

Schema of image processing and bone density measurements.

Figure 2

The result of the densitometry test with automatically added reference lines (a) and the corresponding numerical matrix defining density distribution depending on the projection plane position (b). Identification of the focusing cross-sectional belt zone (c,d) for numerical evaluation. All presented results were measured and calculated for the A result.

Figure 2

The result of the densitometry test with automatically added reference lines (a) and the corresponding numerical matrix defining density distribution depending on the projection plane position (b). Identification of the focusing cross-sectional belt zone (c,d) for numerical evaluation. All presented results were measured and calculated for the A result.

Figure 3

The femoral neck density curve obtained for the A study. Pixels correspond to length units.

Figure 4

Femoral neck density curves obtained for all of the analyzed studies (A–H).

Figure 5

Femoral neck density curves obtained for the studies A, B, D, F (a) and C, E, G, H (b) clearly differ qualitatively.