Rights: The University of Waikato Published 21 July 2007 Download

Dr Ashton Peters from the University of Canterbury talks about how they can use the surface motion of a breast to determine what the internal stiffness is like.

Ashton’s role on the DIET project is to take surface motion information and convert this, using software he has written, into a description of the stiffness within the breast. Hotspots of increased stiffness on the images they produce could point to abnormalities, such as tumours.


My specific role within the DIET research is taking the surface motion information that we can capture, ideally from the surface of a breast and converting that information into a description of stiffness within the breast and hopefully when we look at that stiffness description we can then see where the tumours are based on their stiffness.

I have software programmes that I have written and what they do is they look to convert the surface motion that we have measured into stiffness information, and the way that we do that, is pretty simple really, it’s essentially a guess and check sort of approach, where we guess a stiffness distribution and we use a computer model to calculate if that was the stiffness distribution, what would the surface motion look like. And then we compare that to what is the actual surface motion that we measure and then based on how they are different we update our guess of the stiffness and then we simulate again, and we check is that close to what we actually measured. It’s called an iterative process, and we keep going through that, for several hundred times, and at the end of it we have a stiffness distribution, a guess, that we’ve refined and that guess hopefully shows a very close match to what we measured on the real model, or the breast, and then we know that we have the correct stiffness distribution.

Ideally the final system would be able to take any type of breast, and any type of breast tissue, because breast tissue does vary with age and things like that between people. So we would have a system that can take any breast tissue that we are not sure what the values are, and we can apply this system to it, and we can get from the software, we can get a picture, a three dimensional picture of what the stiffness is like within the breast and we can look through that picture and try and find essentially the hotspots, where is the stiffness high, and hopefully that high stiffness would correspond with an abnormality like a tumour.