that uses a fluorescent substance and a special microscope
to show tumor
margins (edges) so that more of the tumor can be removed. The substance is given by mouth and is taken up by fast-growing cells. These cells light up when seen under a microscope with a special blue light. This may help doctors to remove as much tumor as possible without harming healthy tissue
. Fluorescence-guided surgery
is being studied in the treatment of certain types of brain tumors.