Load single page from large tiff file

I need to implement a function to load a single page from a large tiff.  What would be the best approach?  The code below is just not fast enough.

        // C# 2.0 example
        public IRasterImage LoadPage(string filename, int page)
        {
            RasterCodecs codecs = new RasterCodecs();
            IRasterImage image = codecs.Load(filename);
            image.Page = page;

            return image;
        }

Is there any way to cache the IRasterImage for later calls.  Sometimes I need to come back to the same tiff file for different pages.  I have tried making the IRasterImage a property of the object but somewhere in the process it looses its values.

Help appreciated.

If you know the index of the desired page you want to load, you can try the following load method:

RasterCodecs.Load ( string fileName, int bitsPerPixel, CodecsLoadByteOrder
order, int firstPage, int lastPage)

You can pass the index of the page to the firstPage and lastPage parameters.
Additional tip:
If the files have huge numbers of pages, you can even
improve performance more using some advanced functions that use the Image File
Directory (IFD) of the TIFF file. For details about this, see the help topic "Loading and Saving Large Tiff Files".