backscatter gauging

例句：

1. 1. The backscattering of light from the surface is used to determine the depth of the soil.
   从表面反射的光线的背散射用于确定土壤的深度。
2. 2. In medical imaging, backscattering is used to create images of internal organs.
   在医学成像中，背散射用于创建内部器官的图像。
3. 3. Backscattering can be used to detect the presence of particles in a gas or liquid.
   背散射可以用来检测气体或液体中的粒子存在。