What is another name for the fresnel zone?

The term "Fresnel zone" is synonymous with the "near zone." It refers to the area along the beam path where the ultrasound beam is still converging and has not yet diverged. This zone is characterized by a high intensity and improved resolution because the waves are more coherent and focused. In this region, the energy from the transducer is concentrated, which allows for the creation of better-quality images in ultrasound imaging.

In contrast, the far zone, or far field, indicates the area where the ultrasound beam begins to diverge and is less focused, leading to lower resolution images. The dead zone pertains to the area immediately in front of the transducer where reflections cannot be detected due to limitations in the pulse repetition period, so pathology might be missed. The focal zone describes the area around the focus of the beam where the resolution is at its best but is distinct from the broader region represented by the near zone.