A study on the effects of a calcium drug on the bone mineral density (BMD) by using dual-energy X-ray Absorptiometry (DXA)

摘要

Measurements of osteoporosis might contain errors caused by the calcium drug used in the prevention and the treatment of osteoporosis. This study conducted a lumbar spine phantom experiment to examine whether a calcium drug can influence the measured values of the bone mineral density (BMD) because of the drug taken by a real patient remaining undigested in the stomach. Dual-energy X-ray Absorptiometry (DXA) was used to measure the BMD for a calcium-drug in an equipment-dedicated lumbar spine phantom and 10 patients selected for the BMD measurement. Three types of drugs that are prescribed in actual clinical practice calcium drugs were used for the phantom experiment, and the drugs were divided into a fixed dose, 1/2 of the fixed dose, 1/4 of the fixed dose and 1/8 of the fixed dose. Without the drugs included, the phantom was scanned 60 times continuously to calculate the baseline BMD. The BMD was measured as the calcium drug coated with paraffin was placed in the lumbar vertebra 2 and the soft tissue region of the phantom. To determine when the drug was invisible to the naked eye are measured, the BMD at different drug dilutions. The measurements were conducted three times to calculate the mean. In the patient experiment, patients were selected who visited hospital after taking the drug before measuring the BMD. After a certain time had passed, the BMD was measured again to examine the difference in images and the change in BMD values due to the calcium-drug intake. The BMD measurements of lumbar 1-4 in the phantom were higher, with statistical significant, than the least significant change (LSC) in the bone region for all three drugs (Ca carbonate, Ca citrate and Ca cholecalciferol), showing a significant increase. On the other hand, there was no significant change in the soft tissue. When Ca Cholecalciferol was used in a fixed dose, the BMD of L2 increased by 11. 6%, showing the largest increase among the drugs examined, but only a 2. 8% increase in the BMD of L1-L4 was observed. The dependence of the results on the degree of dilution of the calcium drug showed that the three drugs had values that exceeded the LSC significantly. The measured the BMD was higher in 7 out of 10 patients when the patients took the calcium drug than when they did not. In addition, one of the patients showed a 3. 6% increase in BMD. In addition, the calcium drug appeared in the image in two of the patients who showed an increase in the BMD. This confirmed that the drug remained undigested, with a certain amount of it remaining in the body system. Overall, the measured BMD is affected when the calcium drug taken by a real patient remains undigested in the stomach.