Inclusion Criteria

- INCLUSION CRITERIA:

- Patients with histologically proven intracranial glioma will be eligible for this
protocol. Eligible histologies include glioblastoma multiforme (GBM), gliosarcoma
(GS), anaplastic astrocytoma (AA), anaplastic oligodendroglioma (AO), anaplastic
mixed oligoastrocytoma (AMO), malignant astrocytoma NOS (not otherwise specified),
low grade astrocytoma (LGA), low grade oligoastocytoma (LOA), and low grade
oligodendroglioma (LGO). Patients with radiographically diagnosed or suspected low
grade glioma will also be eligible.

- Patients having undergone recent resection will be eligible as long as all of the
following conditions apply:

- They have recovered from the effects of surgery, not to have been performed
within 2 weeks of the study scan.

- Residual enhancing or non-enhancing disease following resection of recurrent
tumor is mandated for eligibility into the study. To best assess the extent of
residual disease post-operatively, a CT/ MRI should be done:

- no later than 96 hours in the immediate post-operative period, or

- at least 4 weeks post-operatively, and

- within 14 days of registration, and

- on a steroid dosage that has been stable for at least 5 days.

- Normal organ and marrow function defined as: total leukocyte count greater than or
equal to 3000 cells/ul, ANC greater than or equal to 1500 cells/ul, platelet count
greater than or equal to 100,000 cells/ul, serum creatinine less than or equal to 2.0
X upper limit of normal, and bilirubin less than or equal to 1.5X upper limit of
normal, hemoglobin greater than or equal to 9.0 g/dL , serum calcium less than12.0
mg/dL, AST/ALT less than or equal to1.5 times the upper limit of normal, PT less than
or equal to1.5 ULN.

- All patients or their previously designated DPA (if the patient is deemed by the
treating physician to be impaired or questionably impaired in such a way that the
ability of the patient to give informed consent is questionable) must sign an
informed consent indicating that they are aware of the investigational nature of this
study.

- Patients must be greater than or equal to 18 years old.

- Patients must have a Karnofsky performance status of greater than or equal to 60.

- Patients must not have any significant medical illnesses that in the investigator's
opinion cannot be adequately controlled with appropriate therapy or would compromise
the patients' ability to tolerate this study.

- This study was designed to include women and minorities, but was not designed to
measure differences of intervention effects. Males and females will be recruited with
no preference to gender. No exclusion to this study will be based on race. Minorities
will actively be recruited to participate.

EXCLUSION CRITERIA:

- Patients who, in the view of the treating physician, have significant active cardiac,
hepatic, renal, or psychiatric diseases are ineligible.

- Patients who have an active infection.

- Pregnant (positive pregnancy test) or nursing women.

- Patients cannot take loperamide within three days of (11C)dLop imaging.

- Concurrent use of a Pgp inducer as listed in Appendix A within 2 weeks of a study
scan. Use of these medications is allowed over the course of participation in the
study, but must not be administered within 2 weeks of the study imaging.

- Prior participation in other research protocols or clinical care in the last year
such that radiation exposure, including that from this protocol, would exceed the
guidelines set by the Radiation Safety Committee (RSC).

- Patients who have any contraindication to gadolinium enhanced MRI.