I'd like know a free database for free download of medical images in DICOM file format.
Do you know any database?
The NIH (National Institute of Health) has a bunch of free DICOM databases (from actual real patients).
Go check the collection descriptions for more information and for instruction on how to fetch the data.
Somewhere on the DICOM site there are several example images including multiframe images. Also Google turns up quite some sites using "dicom example dataset". Also the "Visible Human Project" is available in DICOM format (again, use Wikipedia and Google).
Besides of this: A "database" with DICOM images has the same value and implications as a database of bank accounts. I'm sure you won't find them on the net for free download.