Sasithorn AmnuaywattakornChanika SritaraKanungnij Thamniratศศิธร อำนวยวัตถากรชนิกา ศรีธราคนึงนิจ ธรรมนิรัตMahidol University. Faculty of Medicine Ramathibodi Hospital. Medical Physics SchoolMahidol University. Faculty of Medicine Ramathibodi Hospital. Department of Diagnostic and Therapeutic Radiology2022-09-302022-09-302022-09-302012Ramathibodi Medical Journal. Vol. 35, No. 2 (Apr-Jun 2012), 114-1210125-3611 (Print)2651-0561 (Online)https://repository.li.mahidol.ac.th/handle/123456789/79763The generalized Least Significant Change (GLSC) is at a 95% confidence interval of precision error in the bone mineral density (BMD). The objectives of the research were to generate the GLSC values among three DXA machines (Lunar Model Prodigy, HOLOGIC Model Discovery A and Discovery W), to predict Bone mineral Density (BMD) values from cross calibration equations and to compare our predicted BMDs. Our research – derived with equation together with those from the manufacturers equations and observed BMDs from actual measurements. BMD measurements were performed on 30 females (age 20 - 80) at the lumbar spine and proximal femur. Each site was measured with all 3 DXA machines twice with repositioning in between. All measurement and analysis steps complied with the ISCD official position. The GLSCs were as follows: between Lunar Prodigy and Hologic Discovery A at the lumbar spine, the neck of femur and the total hip is at 0.066, 0.088, and 0.066 (g/cm2), respectively; between Lunar Prodigy and Hologic Discovery W at the lumbar spine, the neck of femur and the total hip is at 0.064, 0.076, and 0.070. (g/cm2), respectively; between Hologic Discovery A and Hologic Discovery W at the lumbar spine, the neck of femur and the total hip is at 0.020, 0.074, and 0.062 (g/cm2), respectively. The comparison of the errors from both equations found that the lumbar spine and total hip were statistically significant but not statistically significant at the neck of femur. These errors were larger than GLSCs therefore, the calculation of GLSCs by using the data collection was more appropriate for cross calibration of the BMDs than the calculated BMDs from both equations.engMahidol UniversityCross calibrationDXABMDOriginal ArticleMedical Physics School Faculty of Medicine Ramathibodi Hospital Mahidol UniversityDepartment of Diagnostic and Therapeutic Radiology Faculty of Medicine Ramathibodi Hospital Mahidol University