Université Montpellier 1, Montpellier, France.
J Clin Densitom. 2011 Oct-Dec;14(4):395-406. doi: 10.1016/j.jocd.2011.05.004. Epub 2011 Aug 11.
The goal of this study was to assess a new pencil-beam densitometer, the Stratos (Diagnostic Medical Systems, Pérols, France). Evaluation of the dosimetry and precision were done together with an in vivo cross-calibration study performed with the fan beam densitometer Discovery A (Hologic, Bedford, MA). The results indicated that the Stratos performed bone mineral density (BMD) measurements with a good precision, low radiation dose, and good agreement with the Discovery A. The air dose, measured by an ionization chamber, was 40 μGy. The effective dose was assessed using an anthropomorphic phantom and thermoluminescent detectors resulting in 1.96 and 0.31 μSv for a lumbar spine and proximal femur scan, respectively. The average scattered dose rate at a distance of 1m from the device was 1.06 and 1.21 μSv.h(-1) in the lumbar spine and left proximal femur scan mode, respectively. For the precision evaluation, 30 patients underwent 2 lumbar spine and 2 proximal femur scans with repositioning after each scan. The percentage root-mean-square coefficient of variation was 1.22%, 1.38%, 2.11%, and 0.86% for the lumbar spine (L1-L4), lumbar spine (L2-L4), femoral neck, and total hip, respectively. The cross-calibration studies were done on 57 patients (60 ± 9 yr). Lumbar spine, left neck, and left total hip mean BMD were 3.10% lower and 11.94% and 8.83% higher, respectively, with the Stratos compared with the Discovery A. Cross-calibration equations were calculated with a correlation coefficient of 98% (p<0.01) for the lumbar spine (L2-L4), 94% (p<0.01) for the left neck, and 92% (p<0.01) for the left total hip. After standardizing the Stratos measures using the cross-calibration equations, LIN's concordance correlation coefficient was 0.98, 0.93, and 0.92 for the lumbar spine (L2-L4), left neck, and total hip, respectively.
本研究的目的是评估一种新的铅笔束密度计——Stratos（法国Diagnostic Medical Systems 公司生产）。对其剂量测定和精密度进行评估，并与扇形束密度计 Discovery A（美国 Bedford 市 Hologic 公司生产）进行了体内交叉校准研究。结果表明，Stratos 可进行具有良好精密度、低辐射剂量和与 Discovery A 良好一致性的骨矿物质密度（BMD）测量。使用电离室测量空气剂量为 40 μGy。使用人体模型和热释光探测器评估有效剂量，腰椎和股骨近端扫描的结果分别为 1.96 μSv 和 0.31 μSv。在距离设备 1 米处的平均散射剂量率分别为腰椎扫描和左侧股骨近端扫描模式下的 1.06 μSv.h(-1) 和 1.21 μSv.h(-1)。为了进行精密度评估，30 例患者在每次扫描后重新定位，分别进行了 2 次腰椎和 2 次股骨近端扫描。腰椎（L1-L4）、腰椎（L2-L4）、股骨颈和全髋关节的 RMS 变异系数分别为 1.22%、1.38%、2.11%和 0.86%。在 57 例患者（60 ± 9 岁）中进行了交叉校准研究。与 Discovery A 相比，Stratos 测量的腰椎、左侧颈和左侧全髋关节的 BMD 分别低 3.10%，高 11.94%和 8.83%。计算了交叉校准方程，腰椎（L2-L4）的相关系数为 98%（p<0.01），左侧颈的相关系数为 94%（p<0.01），左侧全髋关节的相关系数为 92%（p<0.01）。使用交叉校准方程对 Stratos 测量值进行标准化后，腰椎（L2-L4）、左侧颈和全髋关节的 LIN 一致性相关系数分别为 0.98、0.93 和 0.92。
