Hi!
I have a corrupt ISO file that contains Dicom files and other things.

How can i determine the end of each dicom file within that ISO file?

First I look for "DICM" - 128 to be the start position.
But how can i determine the length of that file?

Today I just take the end as the next DICM-128 characters as the end position
Wich gives me a lot of garbage at the end of each file.

/Tomas

There is no field in a DICOM Part 10 file that indicates the length of the file, nor any end-of-file marker. So the best method might be to parse the file until you reach an invalid data element, and truncate the file at that point. This might require a custom parser, I'm not aware of any DICOM parsers that have an option to do this automatically.

If all the DICOM files contain pixel data, then you could possibly search for the PixelData tag, get its length (or parse the fragments if it's compressed), and then truncate at the end of the element. It's usually (but not always) the last element of the file. You would have to be very careful with this approach, because PixelData also appears in the IconImageSequence, not just in the root.

The ideal, though, is if you could find a CD recovery tool that can do most of the work at the filesystem level. I've had good luck with GNU ddrescue..

Excellent answer!
A lot of Structured Report objects also so it is a bit tricky.
Thanks for the ddrescue info. I tried that one. But still broken. Think it is beyond repair.

Tomas -

There is a utility called DICOM+ that can recover damaged DICOM files.
- Download the pre-built package here: https://github.com/irrer/DICOMClient#user-content-dicom-for
- Unzip and run the DICOM+.bat file.
- Drag and drop DICOM files(s) and folders into it.
- Click the Preview button
- Click the Text radio button
- Click Edit
- Click Save+Close

This will make a copy of the DICOM, recovering as much of each file as possible. When it reads
DICOM files it goes until it reaches a corrupted portion. When it saves files it fixes the internal formatting
so that other utilities can read them.

Good luck!

- Jim

On Friday, April 21, 2023 at 3:08:19 PM UTC-4, tomas moberg wrote:
> Excellent answer!
> A lot of Structured Report objects also so it is a bit tricky.
> Thanks for the ddrescue info. I tried that one. But still broken. Think it is beyond repair.

lördag 22 april 2023 kl. 16:28:00 UTC+2 skrev Jim Irrer:

Realy cool tool.
Good to have.

> Tomas -
>
> There is a utility called DICOM+ that can recover damaged DICOM files.
> - Download the pre-built package here: https://github.com/irrer/DICOMClient#user-content-dicom-for
> - Unzip and run the DICOM+.bat file.
> - Drag and drop DICOM files(s) and folders into it.
> - Click the Preview button
> - Click the Text radio button
> - Click Edit
> - Click Save+Close
>
> This will make a copy of the DICOM, recovering as much of each file as possible. When it reads
> DICOM files it goes until it reaches a corrupted portion. When it saves files it fixes the internal formatting
> so that other utilities can read them.
>
> Good luck!
>
> - Jim
> On Friday, April 21, 2023 at 3:08:19 PM UTC-4, tomas moberg wrote:
> > Excellent answer!
> > A lot of Structured Report objects also so it is a bit tricky.
> > Thanks for the ddrescue info. I tried that one. But still broken. Think it is beyond repair.