No, TSO is not harmonics, however it will work in harmonic mode as well as non harmonic modes. TSO is a way of adjusting the speed of sound assumption that is imbedded in the ultrasound machine image processor. The machine assumes the speed of sound is 1540M/S. In the breast if it is very dense , for example in a breast feeding lady the speed of sound may be more than this and in a fatty involuted breast the speed will be considerably slower. TSO allows us to adjust for this. Simply hold the transducer still and press the auto TSO button. The machine calculates the actual speed of sound in that breast tissue and adjusts the assumed speed accordingly. It only takes a fraction of a second. I re-adjust my TSO as I move around the breast if the amount of glandular tissue Vs fatty tissue changes.
It is really cool technology and keeps the image really sharp.