English: A bone TAC is modelled as a convolution of measured arterial input function with IRF. The estimates for IRF are obtained iteratively to minimise the differences between the bone curve and the convolution of estimated IRF with input function curve. The curve in green shows the initial estimates of the IRF and the blue curve is the final IRF which minimises the differences between the estimated bone curve and the true bone curve. Ki is obtained from the intercept of the linear fit to the slow component of this exponential curve which is considered the plasma clearance to the bone mineral, i.e. were the red line cuts the y axis.