| Objective To study the long-term and short-term precision and short-term accuracy of quality assurance ( QA) in using dual-energy X-ray absorptiometry ( DXA ) .Methods 1 ) Long-term precision: the consecutive 1-year data from QA phantom were statistical analyzed, and the high-, middle-, and low-bone mineral density ( BMD ) , mean BMD, bone mineral content, and projected area of coefficient of variation (CV) were calculated.2)Short-term precision:the data of QA phantom of 25 consecutive days were collected.The mean and standard deviation ( SD) of the high-, middle-, and low-BMD were calculated. The Shewhart chart was created.BMD of the L1-4 vertebral body, bilateral femoral neck, the greater trochanter, ward triangle, and the total hip joint of 30 volunteers was measured.The root mean square of the CV (RMS-CV) was calculated.3) Short-term accuracy:the data of QA phantom of 25 consecutive days were collected.The accuracy of the high-, middle-, and low-BMD were calculated.Results 1) Long-term precision:the CV of high-, middle-, low-BMD, mean BMD, bone mineral content, and projected area was 0.37%, 0.37%, 0.41%, 0.43%, 0.47%, and 0.12%, respectively.2) Short-term precision:the data of QA phantom for 25 consecutive days met the Shewhart rule.The RMS-CV value of L1-4 vertebral body, the bilateral femoral neck, the the bilateral greater trochanter, the the bilateral Ward triangle, and the total hip joint of 30 volunteers was 1.3%, 0.8%, 0.9%, 1.2%, 1.3%, 1.5%, 1.6%, 0.6%, and 0.6%, respectively.3) Short-term accuracy:the accuracy of the data of high-, middle -, low-BMD yielded by scanning QA phantom for 25 consecutive days was -0.07%, 0.10%, and 0.60%, respectively.Conclusion The consistency and reliability of DXA can be reflected by the long-term and short-term precision and accuracy trail.It can effectively raise the credibility of the epidemiological investigation, diagnosis, treatment, and drug testing of osteoporosis. |