Surgeon for tumor cell research in three ways

Needle biopsy - a surgeon can make the scalp and drills a hole in the skull, a small incision.This is called drilling. Doctors of the drilling needle and remove the brain tumor tissue samples.

Stereotactic core needle biopsy - a kind of imaging devices, such as CT or MRI, to control the needle through the hole at the site of tumors. Surgeon with a needle to withdraw tissue samples.

Biopsy at the same time to read - and sometimes the surgeon takes tissue samples, patients, surgery.
Sometimes a biopsy is not possible. If the tumor in the brain stem or other areas, the surgeon can not remove the tumor without damaging normal brain organization. Doctors use MRI, CT and other imaging studies instead.