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.
