Pietrobelli A, Formica C, Wang Z, Heymsfield S B
Obesity Research Center, St. Luke's-Roosevelt Hospital, Columbia University College of Physicians and Surgeons, New York, New York 10025, USA.
Am J Physiol. 1996 Dec;271(6 Pt 1):E941-51. doi: 10.1152/ajpendo.1996.271.6.E941.
Although dual-energy X-ray absorptiometry (DXA) is widely used in clinical research as a means of quantifying body composition, there remains at present little published information that reviews the method's underlying physical basis. Because a clear understanding of DXA physical concepts is integral to appropriate use and interpretation, we present here a three-section review that includes both relevant in vitro and in vivo experimental demonstrations. In the first section we describe the main physical principles on which DXA is based. The section that follows presents a step-by-step analysis of the DXA two-component soft tissue model. In the final section we demonstrate how knowledge of physical concepts can lead to resolution of important methodological concerns, such as the influence of hydration changes on DXA fat estimates. A thorough understanding of DXA physical concepts provides a basis for appropriate interpretation of measurement results and stimulates many new and important research questions.
尽管双能X线吸收法（DXA）作为一种量化身体成分的方法在临床研究中被广泛应用，但目前关于该方法潜在物理基础的公开信息较少。由于清楚理解DXA的物理概念对于正确使用和解读至关重要，我们在此进行一个分为三个部分的综述，其中包括相关的体外和体内实验演示。在第一部分中，我们描述了DXA所基于的主要物理原理。接下来的部分对DXA双成分软组织模型进行了逐步分析。在最后一部分中，我们展示了物理概念的知识如何能够解决重要的方法学问题，例如水合变化对DXA脂肪估计值的影响。对DXA物理概念的透彻理解为正确解释测量结果提供了基础，并引发了许多新的重要研究问题。
