Here the relative moving is between the RBC (red blood cell) in the blood and the source of the ultrasound transducer.
这里发生相对运动的是血中的红细胞和超声换能器的声源。
2
Neither ultrasound or DPL will demonstrate the source of the bleeding, nor can they assess the retroperitoneum or pelvic musculature and the radiograph will demonstrate only the bony anatomy.