Casting byte[] to Int16[]?

How to cast 4'th parameter(DataResponseBuffer) from byte[] to Int16[] from following code?

        byte[] DataResponseBuffer = new byte[4450000];/*Data buffer for storing image data*/
        iRet = SaveGreyScaleBitmap(st_DataPath, uiWidth, uiHeight, DataResponseBuffer);

        private int SaveGreyScaleBitmap(string filename, UInt16 IMGHEIGHT, UInt16 IMGWIDTH, Int16[] ImgBuf)