en Radiation Biology Radiation Biology تحقيق بديع Original Research <span style="font-weight: bold"> Background: </span>Osteoporosis is a chronic disease that contributes substantially to decrease physical activity and decline in the quality of life. Osteoporosis can be diagnosed easily with the use of dual-energy X-ray absorptiometry (DXA) equipment. The aim of this study was to investigate the magnitude of bone loss on proximal femur and lumbar spine LS in pre- and post-menopausal women from Isfahan Osteoporosis Diagnosis Center (IODC) since 2005. <span style="font-weight: bold">Materials and Methods:</span> Bone mineral density (BMD) measurements using DXA have been performed at IODC. 185 pre-menopausal and 174 early post-menopausal women were selected randomly. A Norland XR46 system was used for the investigations. The student t-test was done to find the difference between the T-scores of the femoral neck (FN) and lumbar spine (LS) in pre- and post-menopausal women. <span style="font-weight: bold">Results:</span> Mean BMDs for the FN and LS in pre-menopausal women were 0.859 ± 0.136 and 1.012 ± 0.161 and in post-menopausal women were 0.816 ± 0.119 and 0.919 ± 0.140, respectively. Long-term BMD CVs of 1.0% and 1.2% for the LS and FN were found, respectively. The differences between the FN and LS for pre- and post-menopausal women were t = - 9.02, p < 0.05 and t = -3.50, p < 0.05, respectively.<span style="font-weight: bold"> Conclusion: </span>In spite of, the reported lower BMD T-scores for the LS compared with the FN for women, we found that the FN had significantly lower T-score than LS for both pre- and post-menopausal women. BMD, osteoporosis, proximal femur, lumbar spine, DXA. 103 107 http://ijrr.com/browse.php?a_code=A-10-1-280&slc_lang=en&sid=1 M.R. Salamat 790031947532846001128 790031947532846001128 No N. Rostampour nrostampour@yahoo.com 790031947532846001129 790031947532846001129 Yes S. Shanehsazzadeh 790031947532846001130 790031947532846001130 No M.B. Tavakoli 790031947532846001131 790031947532846001131 No M. Siavash 790031947532846001132 790031947532846001132 No T. Almasi 790031947532846001133 790031947532846001133 No