Scripting on reactor.

Hi folks,

my goal is less a artistic one but more a simulation. I have to simulate a elastic body with the functionality of a pump. Right I'm talking about the heart.
I'll get my models by applying "volume rendering" on MRI-data.

But here is the thing I have to simulate tissues, which I have a lot of equations for. So my question is, is it possible to implement stuff programmatically and use it with the Reactor engine, scripting on physics, creating my own materials?

I hope I could make myself clear.

thx in Advance