Can somebody explain me what does 'in situ' mean in

>>273919
I assume it means "when the probe is placed in an oesophagus".

>>273921
Yeah, but what those 5 mm mean? 5 mm deep?

>>273929
That would be "5mm away from the probe", surely?

Inverse square law and all.

>>273919

To make clear they do mean there where the device will be used and not in VITRO. In vitro values often have just a very limited apllicability to the real usage of something, in situ values are the best ones- and as such when they have some they give them.
As for the 5mm, that has to do with how sound power is measured, you see, the energy per x mm only has a use for you when you know which distance was used as sound energy dissipates quickly, so you need a standard value for comarison purposes, and they chose 5 mm.

>>273956
>which distance was used as sound energy dissipates quickly

And that distance is between what? The probe and the monitored object?

>>273962

Likely.
The given unit is the sound intensity. Taht one is nomrally measured by having two microphones in close proximity in the direction of sound and calculating the differential quotient- but that would be in vitro. How they calculated or measured in situ- no idea, but it can only mean the distance between the device in opeational direction and measurement point.