For Each ctrl As Control In Me.Panel1.Controls
  If ctrl.GetType Is GetType(RadioButtonList) Then
    Dim c As RadioButtonList = DirectCast(ctrl, RadioButtonList)
    PrintLn(c.ID)
    For Each item As ListItem In c.Items
      PrintLn(String.Format("{0} = {1}", item.Text, item.Value))
    Next
    PrintLn()
  End If
Next

Dim tipo As Type = Type.GetType(Me.GetType().FullName)
Dim radioButtonListNames = tipo.GetFields(BindingFlags.NonPublic Or BindingFlags.Instance).Where(Function(t) t.FieldType = GetType(RadioButtonList)).[Select](Function(t) t.Name).ToList()
If radioButtonListNames.Count = 0 Then
  PrintLn("Nessun RadioButtonList trovato")
Else
  For Each s In radioButtonListNames
    PrintLn(s)
  Next
End If