The present invention provides for a secure, two-way transmission of medical data over the Internet and through the hospital's firewall using push and pull mechanisms. More particularly, the present invention utilizes standard SSH technology and the rsync and scp protocols to enable secure, cost-effective data transmission over the Internet. The hospital firewall is traversed through the use of an agent located behind the hospital's firewall. The agent utilizes a push mechanism to push the raw scan data through the firewall and over the Internet to the outside third party; and the agent uses a pull mechanism to reach through the firewall and over the Internet to retrieve the data processed by the outside third party. In other words, the present invention transfers data from the hospital to the third party by initiating a data push mechanism from behind the hospital firewall; and transfers the processed data from the outside third party back into the hospital by initiating a data pull mechanism from behind the hospital firewall. The aforementioned agent acts as a broker for the foregoing data transmission and also encodes how the data should be handled once it is received on the hospital side.