A letter from your physician stating the diagnosis of your conditions and the nature of treatment you are requiring.

A letter from a licensed medical facility in the U.S. showing that you have been accepted for treatment and you has an appointment. It must include an estimate of the total time and total cost of your treatment including outpatient care if you will not be able to return.

Evidence to show that you have funds needed to pay all anticipated expenses. If a close relative in the U.S. an Affidavit of Support (Form I-134) provides it is to be produced

A show of significant resources, controlled by the patient, which are sufficient for use in meeting expenses, or

A letter from the treating institution, indicating that all expenses of treatment in the United States will be covered by the institution itself.