Three categories of special immigrants established by Public Law 96-70 (Act of 9/27/79): 1) certain former employees of the Panama Canal Company or Canal Zone Government, their spouses and accompanying children; 2) certain former employees of the U.S. Government in the Panama Canal Zone who are Panamanian nationals, their spouses and children; and 3) certain former employees of the Panama Canal Company or Canal Zone Government on April 1, 1979, their spouses and children. The Act provides for admission of a maximum of 15,000 immigrants, at a rate of no more than 5,000 each year.
Panel Physician – A medically trained, licensed and experienced doctor practicing overseas who is appointed by the local U.S. Embassy or Consulate. These medical professionals receive U.S. immigration-focused training in order to provide examinations as required by the CDC (Center for Disease Control and Prevention) and USCIS (U.S. Citizenship and Immigration Services). For medical examinations given in the U.S., please see Civil Surgeon.
IMPORTANT: medical examinations given overseas will not be recognized if they are given by a doctor who is not appointed by the local U.S. Consulate or Embassy; please be sure that your medical exam is being given by a Panel Physician or your results and documents will be invalid.

This definition is in context to Citizenship. See more contextual defintions for Panama Canal Act Immigrants.