Wave impedance inversion is essential in predicting reservoir properties and sand-body distribution, and plays an important role in seismic survey.

This would also explain their somewhat 'random' distribution in areas of the body which would not have been that easy to display had they been applied as a form of status marker.

Dr Kate Law, of cancer Research UK, said it was not yet clear how nutrients, or the amount and distribution of body fat affected the risk of developing cancer.