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BPnd (Ichise MRTM Ref) Ichise Multi-linear Reference Tissue Model

To reduce noise-related bias effects arising in the MRTM0 method, Ichise et al. [24] applied a strategy known to be effective in reducing the noise-induced bias for the models requiring blood data. To this end the equation of the MRTM0 was rearranged to remove the noisy tissue radioactivity term C(t) from the independent variables. This approach resulted in a new method called MRTM with the following operational equation.

Equation MRTM

C(t) is the TAC from a receptor-rich region (k3>0), and C'(t) the TAC from a region without receptors (k3=0 in the 2-tissue compartment model).

The multi-linear relationship above can be solved using multi-linear regression, yielding three regression coefficients. The binding potential can then be calculated from the first two regression coefficients g1 and g2 by

Equation MRTM BP

Furthermore, division of the first by the third regression coefficient yields an estimate of k2' .