Deleting or Over-writing Files which have been read from disk
Image files which have been read by DicomObjects using ReadFile (COM) or Read (.NET) cannot normally be deleted (or over-written using Write/WriteFile etc.) until the file is released. This is because pixel data from the files is read “as needed” (using memory mapping for COM or a duplicate FileStream for .NET). This behaviour is enabled by default, causing only the data actually needed at any time to be read into memory.