C11-Sodium Acetate PET/CT Imaging Evaluation in Brain Glioma, Post Therapy Necrosis and Pseudo-progression

The study is designed to investigate the effectiveness of Carbon Acetate PET/CT (AC PET)in
terms of its ability to distinguish between radionecrosis/pseudo-progression and viable
tumor in patients previously treated with surgery and radiation for high grade glioma brain
tumors.

Eligible patients with biopsy proven high grade gliomas (WHO grades 3 and 4) status-post
prior cranial irradiation for this tumor; age 18 to 70; ECOG/Zubrod of 0-2, no other
contraindications to trial entry, and a post-irradiation cranial MRI or CT demonstrating an
enhancing lesion of uncertain etiology (not biopsied) will be treated with at least two
weeks of steroidal therapy.

Responders to steroidal therapy will be classified as either pseudo-progression (if
asymptomatic) or radionecrosis (if symptomatic). Non-responders (those who do not respond
clinically, radiographically, or both) will be referred for an FDG PET/CT and initial AC
PET/CT within 3 weeks, and subsequently referred for stereotactic biopsy of their lesion
followed by focal laser treatment (in the same operative setting) within 3 weeks of AC
PET/CT.

Specific Goals/Questions:

1. What is the yield (sensitivity, accuracy, positive and negative predictive value) of
state-of-the-art PET/CT with C-11 Acetate in detecting recurrent disease versus post
treatment effects and pseudo-progression in this patient population?

2. How does the performance of PET with C-11 Acetate compare with that of PET using F-18
fluorodeoxyglucose (FDG-PET) and with that of MRI?

3. Evaluate the optimal timing for post injection imaging.

Inclusion Criteria:

- Patients age 18-70

- Pathologically confirmed World Health Organization (WHO) grade 3 or 4 glioma

- ECOG/Zubrod 0-2

- Prior external beam radiotherapy to 59.4-60 Gray by 1.8-2 Gy fractions

- Post-radiotherapy contrast-enhanced cranial MRI obtained at least 6 weeks after the
completion of external beam radiotherapy shows enhancing anomaly
(recurrent/progressive tumor versus pseudo-progression versus radionecrosis)

- Patient completed at least a two week course of palliative steroid therapy for this
enhancing anomaly

- No prior designated therapy other than steroids for presumed radionecrosis or
recurrent tumor

- Patient with no clinical and/or radiological response to steroid therapy

- Patient eligible for stereotactic brain biopsy

- Patient eligible for focal laser therapy

Exclusion Criteria:

- Patients under the age of 18 years

- Claustrophobic patients