It is possible to choose which outgoing interface to use when making an outgoing DICOM association using code such as below:

 using (var socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp))
 {
	var localEP = new IPEndPoint(IPAddress.Parse("outgoingIP"), 0); // 0 means any available port
	socket.Bind(localEP);
	var remoteEP = new IPEndPoint(IPAddress.Parse("remoteIP"), remotePort);
	socket.Connect(remoteEP);
	NetworkStream ns = new NetworkStream(socket, true);                
	DicomAssociation cn = new DicomAssociation();
	cn.RequestedContexts.Add("1.2.840.10008.1.1");    
	cn.Open(socket, ns, "callingAET", "calledAET");
	int status = cn.Echo();
	cn.Close();
 }