biomedical and comsol

Hi there,
I am planning to use comsol for my project in which i have to simulate the forward problem of bioelectromagnetic.
Since i am new to this package, therefore, i have quite a few questions in my mind. I hope you would not mind answering these questions.
If i need to model a 3 or 4 layer spherical head model in comsol, which solver would be the best one, keeping in mind all layers are homogeneous and isotropic and i would be using quasi-static electromagnetic module.
How to define current dipoles within the spherical head model.
Which package would you recommend to import the medical images for 3d head modelling?

Thanks
Salman