Private tag support

[Jingkun4dcmtk]

Dear Dev team,

I’m trying to extend dcmtk to support private tags via my own xyz.dic. I was able to generate or convert my xyz.dic to xyz.h, as shown below:

(0011,"Jhu-X",10) LO JhuGroup11 1 PrivateTag

(0011,"Jhu -X",01) CS PatientType 1 PrivateTag

(0011,"Jhu -X",02) CS PatientStatus 1 PrivateTag

(0011,"Jhu -X",03) LO PlanUuid 1 PrivateTag

(0011,"Jhu -X",04) LO TrackingMaskUuid 1 PrivateTag

(0011,"Jhu -X",05) LO PatientUuid 1 PrivateTag

(0011,"Jhu -X",06) LO PatientPictureUuid 1 PrivateTag

The generated tags are:
#define DCM_PatientUID DcmTagKey(0x0011, 0x0003)

#define DCM_PatientType DcmTagKey(0x0011, 0x0001)

#define DCM_PatientStatus DcmTagKey(0x0011, 0x0002)

#define DCM_PlanUuid DcmTagKey(0x0011, 0x0003)

#define DCM_TrackingMaskUuid DcmTagKey(0x0011, 0x0004)

#define DCM_PatientUuid DcmTagKey(0x0011, 0x0005)

#define DCM_PatientPictureUuid DcmTagKey(0x0011, 0x0006)

#define DCM_JhuGroup11 DcmTagKey(0x0011, 0x0010)

When adding tags to DICOM file in the following way:
dcmDS->putAndInsertString(DCM_JhuGroup11, "Jhu-X");

dcmDS->putAndInsertString(DCM_PatientType, "Phantom");

dcmDS->putAndInsertString(DCM_PatientStatus, "New");
…
Only DCM_JhuGroup11 is added successfully.

Can you help me get my other tags added? Basically I'd like to operate (read/write) private tags like public ones by extending the public dictionary.

Thanks,
Jack

[J. Riesmeier]

Apparently, the VR is missing for your private tags. By the way, there is a "Howto" on adding private data elements to a DICOM dataset: https://support.dcmtk.org/redmine/proje ... rivateData

[Jingkun4dcmtk]

Hi J. Riesmeier,

I'm able to add private tags via the instructions provided by "Howto" already. However, I don't want to use that approach of registering private tags at runtime. My understanding is that private tag support can also be achieved by extending the dicom.dic as described in https://support.dcmtk.org/docs/file_datadict.html so that private tags will be able to be used in the same way as public tags.

So I did the following:
1. create my own myprivate.dic by following your private.dic
2. generate private.h using myprivate-mkdeftag.h

What other steps do I need to do in order to use those private tags defined in myprivate.dic?

BTW, you pointed out that "VR missing"? I did have VR defined in my private tag definition, e.g., (0011,"Jhu-X",10) LO JhuGroup11 1 PrivateTag.

Thanks,
Jingkun

[J. Riesmeier]

My understanding is that private tag support can also be achieved by extending the dicom.dic as described in https://support.dcmtk.org/docs/file_datadict.html so that private tags will be able to be used in the same way as public tags.

That's correct.

generate private.h using myprivate-mkdeftag.h

This is not really necessary, and your DcmTagKey definitions also seem to be wrong [*], e.g. instead of

Code: Select all

#define DCM_PatientUID DcmTagKey(0x0011, 0x0003)

it should be

Code: Select all

#define DCM_PatientUID DcmTagKey(0x0011, 0x1003, "Jhu-X")

because otherwise the DCMTK would not be able to determine the VR. This would have been more obvious, I guess, if you would have checked the return value of the putAndInsertString() calls.

HTH

[*] The mkdeftag tool does not support DcmTagKey definitions for private tags, AFAICR. This is because creating DCM_xxx names from the private tags in the "private.dic" file that is shipped with the DCMTK is probably not possible.

[Jingkun4dcmtk]

Hi J. Reismeier,

In
#define DCM_PatientUID DcmTagKey(0x0011, 0x1003, "Jhu-X"), DcmTagKey can't take 3 parameters though. Did I miss any point?

Thanks,
Jingkun

[J. Riesmeier]

Sorry, I wanted to refer to DcmTag (not DcmTagKey), which has two constructors that allow for specifying the Private Creator identifier as an optional parameter (see documentation).

[Jingkun4dcmtk]

Hi J. Reismeier,

That does the trick!

I'm able to write and read my private tags as expected.

Your help is greatly appreciated!

Thanks,
Jingkun