TRadioButton dentro de um TListbox

procedure TForm1.ListBox1DrawItem(Control: TWinControl; Index: Integer;
  Rect: TRect; State: TOwnerDrawState);
var
  drawRect: TRect;
begin
  with ListBox1.Canvas do
  begin
    FillRect(rect);

    drawRect.Left := rect.Left + 1;
    drawRect.Right := Rect.Left + 13;
    drawRect.Bottom := Rect.Bottom;
    drawRect.Top := Rect.Top;

    if odSelected in State then
      DrawFrameControl(Handle, drawRect, DFC_BUTTON, DFCS_BUTTONRADIO or DFCS_CHECKED)
    else
      DrawFrameControl(Handle, drawRect, DFC_BUTTON, DFCS_BUTTONRADIO);

    TextOut(15, rect.Top + 3, ListBox1.Items[Index]);
  end;
end;