 Following craniotomy, patients will undergo intraoperative placement of a single Light Source, centrally placed within the tumor, under direct visualization prior to tumor resection. Following placement of the light source with the depth of the end of the light bar from the cortical surface to be calculated from the pre-operative MRI and spiral CT scan, so as to be centralized within the main tumor bulk, light will be delivered following a predetermined escalation schedule either 100 Jcm or 200 Jcm at 20 mWcm light energy for a treatment time of 1 hour 24 minutes 100Jcm or 2 hours 46 minutes 200 Jcm. The Light Source will then be manually removed and the tumor maximally resected. 