Inclusion Criteria:

- At least 18 years old.

- Prior histological diagnosis of high grade glioma (HGG) with prior initial treatment
and radiation therapy for HGG; recurrence of HGG suspected, and care plan includes
surgical procedure.

- Undergoing surgical procedure for clinical reasons, and gross surgical resection not
expected.

- Neurosurgeon is planning stereotactic biopsy or tumor debulking for clinical reasons;
frozen tissue confirmation of malignancy during this operative procedure is
necessary.

- Neurosurgeon evaluates that placement of oxygen monitoring probe after biopsy or
debulking can be done safely without complications.

- Contrast enhancing disease on MRI within 21 days prior to enrollment.

- Karnofsky Performance Score ≥ 60 at Screening.

- Recovered from toxicity of prior antineoplastic therapy, and off cytotoxic
chemotherapy for 7 days prior to Screening.

- Recovered from prior radiotherapy and had at least 21 days elapse since completion of
radiotherapy prior to Screening.

- Recovered from prior surgery for their brain tumor in investigator's clinical
judgment.

- If female, negative serum or urine pregnancy test at Screening.

- Within 2 weeks of starting study, hematologic and renal functions as specified:
Absolute neutrophil count ≥ 1500/mm3, platelets ≥ 100,000/mm3, hemoglobin ≥ 9.0g/dL,
creatinine ≤ 1.7mg/dl, serum bilirubin ≤ 1.5mg/dL, blood urea nitrogen within 2 times
the upper limit of normal, transaminases ≤ 4 times above the upper limits of the
institutional norm, and prothrombin time and partial thromboplastin time within
institutional norm or below.

- Patient or patient's medical power of attorney provided written consent to
participate in the study.

- Mini Mental Status Exam score ≥ 15.

Exclusion Criteria:

- Pregnant or lactating.

- Receiving concurrent cytotoxic chemotherapy for their tumor within 7 days prior to
Screening, or decision is made at the time of surgery to treat with other modality of
treatment (e.g., gliadel wafers).

- Serious concurrent infection or medical illness which would jeopardize the ability of
the patient to safely participate.

- Behavioral, cognitive, or psychiatric disease or personal situation that might
interfere with optimal participation.

- Cannot undergo an MRI.

- Received an investigational drug not approved for human use by the FDA within 30 days
of enrollment.

- Previously received TSC.