Inclusion Criteria:

- 18 years of age or older

- Histological or cytological diagnosis of neoplasm

- No effective standard therapeutic options

- ECOG performance status of 0-2

- ≥ to 4 weeks post therapeutic radiation or chemotherapy(≥ to 6 weeks for nitrosureas)
and recovery (to baseline status) from associated acute toxicities. Patients
previously treated with non-cytotoxic therapy and who have recovered from or have
controlled drug-associated toxicity are allowed to enter the trial after a period
consisting of 4 half-lives of the agent.

- Negative serum pregnancy test for women of child-bearing potential within one week
prior to treatment with investigational agents (99mTc-EC20 and EC0225)

- Adequate bone marrow reserve, renal and hepatic function

Exclusion Criteria:

- Concurrent malignancies

- Women who are pregnant or lactating

- Evidence of symptomatic brain metastases

- Receiving concomitant anticancer therapy (excluding supportive care)

- Requires palliative radiotherapy at time of study entry

- Unable to tolerate conditions for radionuclide imaging

- Administration of another radiopharmaceutical that would interfere with assessment of
99mTc-EC20