How to invoke C-STORE when trying to query from SCP

Question

I've been using the following code, which is from the pynetdicom library to query and store some images from a remote server SCP, on my machine(SCU).

"""
Query/Retrieve SCU AE example.

This demonstrates a simple application entity that support the Patient
Root Find and Move SOP Classes as SCU. In order to receive retrieved
datasets, this application entity must support the CT Image Storage
SOP Class as SCP as well. For this example to work, there must be an
SCP listening on the specified host and port.

For help on usage,
python qrscu.py -h
"""

import argparse
from netdicom.applicationentity import AE
from netdicom.SOPclass import *
from dicom.dataset import Dataset, FileDataset
from dicom.UID import ExplicitVRLittleEndian, ImplicitVRLittleEndian, \
    ExplicitVRBigEndian
import netdicom
# netdicom.debug(True)
import tempfile

# parse commandline
parser = argparse.ArgumentParser(description='storage SCU example')
parser.add_argument('remotehost')
parser.add_argument('remoteport', type=int)
parser.add_argument('searchstring')
parser.add_argument('-p', help='local server port', type=int, default=9999)
parser.add_argument('-aet', help='calling AE title', default='PYNETDICOM')
parser.add_argument('-aec', help='called AE title', default='REMOTESCU')
parser.add_argument('-implicit', action='store_true',
                    help='negociate implicit transfer syntax only',
                    default=False)
parser.add_argument('-explicit', action='store_true',
                    help='negociate explicit transfer syntax only',
                    default=False)

args = parser.parse_args()

if args.implicit:
    ts = [ImplicitVRLittleEndian]
elif args.explicit:
    ts = [ExplicitVRLittleEndian]
else:
    ts = [
        ExplicitVRLittleEndian,
        ImplicitVRLittleEndian,
        ExplicitVRBigEndian
    ]

# call back


def OnAssociateResponse(association):
    print "Association response received"


def OnAssociateRequest(association):
    print "Association resquested"
    return True


def OnReceiveStore(SOPClass, DS):
    print("FINALLY ENTERED")
    print "Received C-STORE", DS.PatientName
    try:
        # do something with dataset. For instance, store it.
        file_meta = Dataset()
        file_meta.MediaStorageSOPClassUID = '1.2.840.10008.5.1.4.1.1.2'
        # !! Need valid UID here
        file_meta.MediaStorageSOPInstanceUID = "1.2.3"
        # !!! Need valid UIDs here
        file_meta.ImplementationClassUID = "1.2.3.4"
        filename = '%s/%s.dcm' % (tempfile.gettempdir(), DS.SOPInstanceUID)
        ds = FileDataset(filename, {},
                         file_meta=file_meta, preamble="\0" * 128)
        ds.update(DS)
        #ds.is_little_endian = True
        #ds.is_implicit_VR = True
        ds.save_as(filename)
        print "File %s written" % filename
    except:
        pass
    # must return appropriate status
    return SOPClass.Success


# create application entity
MyAE = AE(args.aet, args.p, [PatientRootFindSOPClass,
                             PatientRootMoveSOPClass,
                             VerificationSOPClass], [StorageSOPClass], ts)
MyAE.OnAssociateResponse = OnAssociateResponse
MyAE.OnAssociateRequest = OnAssociateRequest
MyAE.OnReceiveStore = OnReceiveStore
MyAE.start()


# remote application entity
RemoteAE = dict(Address=args.remotehost, Port=args.remoteport, AET=args.aec)

# create association with remote AE
print "Request association"
assoc = MyAE.RequestAssociation(RemoteAE)


# perform a DICOM ECHO
print "DICOM Echo ... ",
st = assoc.VerificationSOPClass.SCU(1)
print 'done with status "%s"' % st

print "DICOM FindSCU ... ",
d = Dataset()
d.PatientsName = args.searchstring
d.QueryRetrieveLevel = "PATIENT"
d.PatientID = "*"
st = assoc.PatientRootFindSOPClass.SCU(d, 1)
print 'done with status "%s"' % st

for ss in st:
    if not ss[1]:
        continue
    # print ss[1]
    try:
        d.PatientID = ss[1].PatientID
    except:
        continue
    print "Moving"
    print d
    assoc2 = MyAE.RequestAssociation(RemoteAE)
    gen = assoc2.PatientRootMoveSOPClass.SCU(d, 'SAMTEST', 1)
    for gg in gen:
        print
        print gg
    assoc2.Release(0)
    print "QWEQWE"

print "Release association"
assoc.Release(0)

# done
MyAE.Quit()

Running the program, I get the following output:

Request association
Association response received
DICOM Echo ...  done with status "Success "
DICOM FindSCU ...  done with status "<generator object SCU at 0x106014c30>"
Moving
(0008, 0052) Query/Retrieve Level                CS: 'PATIENT'
(0010, 0010) Patient's Name                      PN: 'P*'
(0010, 0020) Patient ID                          LO: 'Pat00001563'
Association response received
QWEQWE
Moving
(0008, 0052) Query/Retrieve Level                CS: 'PATIENT'
(0010, 0010) Patient's Name                      PN: 'P*'
(0010, 0020) Patient ID                          LO: 'Pat00002021'
Association response received
QWEQWE
Release association

Echo works so I know my associations are working and I am able to query and see the files on the server as suggested by the output. As you can see however, OnReceiveStore does not seem to be called. I am pretty new to DICOM and I was wondering what might be the case. Correct me if I am wrong but I think the line gen = assoc2.PatientRootMoveSOPClass.SCU(d, 'SAMTEST', 1) is supposed to invoke OnReceiveStore. If not, some insight on how C-STORE should be called is appreciated.

Answer 1

DICOM C-MOVE is a complicated operation, if You are not very familiar with DICOM.

You are not calling OnReceiveStore Yourself, it's called when the SCP starts sending instances to Your application. You issue a C-MOVE command to the SCP with Your own AE title, where You want to receive the images. In Your case SAMTEST. Since this is the only parameter for the C-MOVE command, then the SCP needs to be configured before-hand to know the IP and port of the SAMTEST AE. Have You done this?

I don't know, why the code is not outputting responses from the SCP to the C-MOVE command. It looks like it should. These could give a good indication, what is happening. You can also check the logs on the SCP side, to see, what's happening.

Also, here is some quite good reading about C-MOVE operation.