35 Year Old's Brain

This is from an MRI of my brain. The MRI was taken as part of a neuroscience project, so it's healthy, and I have no problems releasing it.
To create the STL, I imported the DICOM files into the open source scientific visualization package Paraview, and then created an isosurface from it. There are some scanning artifacts that I was not completely able to remove (at the very top)

This is my first "thing" My goal is to make a keychain out of it, so I'm trying to get a print that is ~1" in the maximal direction. Currently, I have access to an Ultimaker, and am printing out an overlarge version, just to get the hang of it. My first attempt was rubbish; now I'm trying with a raft and scaffolding. Any tips would be most welcome.

Ideally, I'd eventually like to cast this in bronze or aluminum (after adding a keychain loop), so any Lost PLA tips would be handy too!