Many types of cancers overexpress a receptor for the vitamin folate (Folate Receptor). This Phase 2 study will utilize a standard imaging radionuclide, technetium-99m, conjugated to a ligand (EC20) designed to bind to the folate receptor. The study is designed as an open-label, baseline-controlled study.

This is a Phase 2 open-label, single-treatment group, baseline-controlled study designed to verify product safety, gather data on the percentage of subjects with pituitary tumors with increased uptake of FolateScan in tumors and correlate the immunohistochemical staining findings with the FolateScan images, in subjects with pituitary tumors.

Inclusion Criteria:

Subjects must meet the following eligibility requirements to be enrolled in the study:

1. Subject must be 18 years of age or older.
2. Subject must have a pituitary tumor.
3. Subject must have good kidney function.

3. Subject must provide written informed consent prior to enrollment.

Exclusion Criteria:

Subjects must be excluded if any of the following conditions are present:

1. Subject is pregnant or breastfeeding.
2. Subject is simultaneously participating in another investigational drug study.
3. Subject has completed the follow-up phase of any previous study loess than 30 days prior to enrollment in this study.
4. Subject is unable to tolerate conditions for radionuclide imaging.
5. Subject has been administered another radiopharmaceutical that would interfere with the assessment of Technetium Tc 99m EC20.