A Python implementation of the DICOM networking protocol, originally based on (legacy) pynetdicom.
DICOM is the international standard for medical images and related information. It defines the formats and communication protocols for media exchange in radiology, cardiology, radiotherapy and other medical domains.
pynetdicom is a pure Python (2.7/3.5+) package that implements the DICOM networking protocol. Working with pydicom, it allows the easy creation of DICOM Service Class Users (SCUs) and Service Class Providers (SCPs).
pynetdicom's main user class is
AE,
which is used to represent a DICOM Application Entity. Once an AE has been
created you can:
- Start the application as an SCP by specifying the supported presentation contexts then calling AE.start_server() and waiting for incoming association requests
- Use the application as an SCU by specifying the presentation contexts you want the peer SCP to support, then requesting an association via the AE.associate() method, which returns an Association thread.
Once associated, the services available to the association can be used by sending DIMSE-C and DIMSE-N messages.
The pynetdicom tutorials, user guide, code examples, application and API reference documentation is available for the current release as well as the development version.
Using pip:
$ pip install pynetdicomUsing conda:
$ conda install -c conda-forge pynetdicom$ pip install git+git://github.com/pydicom/pynetdicom.gitWhen the AE is acting as an SCU and an association has been established with a peer SCP, the following DIMSE-C and -N services are available:
Where dataset is a pydicom Dataset object, query_model is a UID string, identifier_list is a list of pydicom Tag objects, event_type and action_type are ints and class_uid and instance_uid are UID strings. See the Association documentation for more information.
When the AE is acting as an SCP the following DIMSE-C and -N services are available to the peer once an association has been established:
| DIMSE service | Intervention Event | Handler documentation |
|---|---|---|
| C-ECHO | evt.EVT_C_ECHO |
Handle C-ECHO |
| C-FIND | evt.EVT_C_FIND |
Handle C-FIND |
| C-GET | evt.EVT_C_GET |
Handle C-GET |
| C-MOVE | evt.EVT_C_MOVE |
Handle C-MOVE |
| C-STORE | evt.EVT_C_STORE |
Handle C-STORE |
| N-ACTION | evt.EVT_N_ACTION |
Handle N-ACTION |
| N-CREATE | evt.EVT_N_CREATE |
Handle N-CREATE |
| N-DELETE | evt.EVT_N_DELETE |
Handle N-DELETE |
| N-EVENT-REPORT | evt.EVT_N_EVENT_REPORT |
Handle N-EVENT-REPORT |
| N-GET | evt.EVT_N_GET |
Handle N-GET |
| N-SET | evt.EVT_N_SET |
Handle N-SET |
With the exception of the C-ECHO service, a user-defined callable function,
handler, must be bound to the corresponding
intervention event
in order to complete a DIMSE service request. Events
can be imported with from pynetdicom import evt and a handler can be
bound to an event prior to starting an association through the evt_handlers
keyword arguments in
AE.start_server()
and
AE.associate().
When an event occurs the handler function is called and passed a single
parameter, event, which is an
Event
object whose specific attributes
are dependent on the type of event that occurred. Handlers bound to
intervention events must return or yield certain values. See the
handler documentation
for information on what attributes and properties are available in Event
for each event type and the expected returns/yields for the
corresponding handlers.
Some basic DICOM applications are included with pynetdicom:
More code examples are available in the documentation.
Send a C-ECHO request to a Verification SCP (at TCP/IP address addr, listen port number port):
from pynetdicom import AE
ae = AE(ae_title=b'MY_ECHO_SCU')
# Verification SOP Class has a UID of 1.2.840.10008.1.1
# we can use the UID str directly when adding the requested
# presentation context
ae.add_requested_context('1.2.840.10008.1.1')
# Associate with a peer AE
assoc = ae.associate(addr, port)
if assoc.is_established:
# Send a DIMSE C-ECHO request to the peer
status = assoc.send_c_echo()
# Print the response from the peer
if status:
print('C-ECHO Response: 0x{0:04x}'.format(status.Status))
# Release the association
assoc.release()Create a blocking Echo SCP on port 11112 (you may optionally
bind a handler to the evt.EVT_C_ECHO event if you want to return something
other than an 0x0000 Success status):
from pynetdicom import AE, VerificationPresentationContexts
ae = AE(ae_title=b'MY_ECHO_SCP')
# Or we can use the inbuilt VerificationPresentationContexts list,
# there's one for each of the supported Service Classes
# In this case, we are supporting any requests to use Verification SOP
# Class in the association
ae.supported_contexts = VerificationPresentationContexts
# Start the SCP on (host, port) in blocking mode
ae.start_server(('', 11112), block=True)Alternatively, you can start the SCP in non-blocking mode, which returns the running server instance. This can be useful when you want to run a Storage SCP and make C-MOVE requests within the same AE.
In the next example we'll create a non-blocking Verification SCP and bind a
handler for the C-ECHO service request event evt.EVT_C_ECHO that logs the
requestor's address and port number and the timestamp for the event.
import logging
from pynetdicom import AE, evt, debug_logger
from pynetdicom.sop_class import VerificationSOPClass
# Setup logging to use the StreamHandler at the debug level
debug_logger()
ae = AE(ae_title=b'MY_ECHO_SCP')
ae.add_supported_contexts(VerificationSOPClass)
# Implement the EVT_C_ECHO handler
def handle_echo(event, logger):
"""Handle a C-ECHO service request.
Parameters
----------
event : evt.Event
The C-ECHO service request event, this parameter is always
present.
logger : logging.Logger
The logger to use, this parameter is only present because we
bound ``evt.EVT_C_ECHO`` using a 3-tuple.
Returns
-------
int or pydicom.dataset.Dataset
The status returned to the peer AE in the C-ECHO response.
Must be a valid C-ECHO status value as either an ``int`` or a
``Dataset`` object containing an (0000,0900) *Status* element.
"""
# Every *Event* includes `assoc` and `timestamp` attributes
# which are the *Association* instance the event occurred in
# and the *datetime.datetime* the event occurred at
requestor = event.assoc.requestor
timestamp = event.timestamp.strftime("%Y-%m-%d %H:%M:%S")
msg = (
"Received C-ECHO service request from ({}, {}) at {}"
.format(requestor.address, requestor.port, timestamp)
)
logger.info(msg)
# Return a *Success* status
return 0x0000
# By binding using a 3-tuple we can pass extra arguments to
# the handler
handlers = [(evt.EVT_C_ECHO, handle_echo, [logging.getLogger('pynetdicom')])]
# Start the SCP in non-blocking mode
scp = ae.start_server(('', 11112), block=False, evt_handlers=handlers)
# Associate and send a C-ECHO request to our own Verification SCP
ae.add_requested_context(VerificationSOPClass)
assoc = ae.associate('localhost', 11112)
if assoc.is_established:
status = assoc.send_c_echo()
assoc.release()
# Shutdown the SCP
scp.shutdown()Send the DICOM CT Image Storage dataset in file-in.dcm to a peer Storage SCP (at TCP/IP address addr, listen port number port):
from pydicom import dcmread
from pydicom.uid import ImplicitVRLittleEndian
from pynetdicom import AE, VerificationPresentationContexts
from pynetdicom.sop_class import CTImageStorage, MRImageStorage
ae = AE(ae_title=b'MY_STORAGE_SCU')
# We can also do the same thing with the requested contexts
ae.requested_contexts = VerificationPresentationContexts
# Or we can use inbuilt objects like CTImageStorage.
# The requested presentation context's transfer syntaxes can also
# be specified using a str/UID or list of str/UIDs
ae.add_requested_context(CTImageStorage,
transfer_syntax=ImplicitVRLittleEndian)
# Adding a presentation context with multiple transfer syntaxes
ae.add_requested_context(MRImageStorage,
transfer_syntax=[ImplicitVRLittleEndian,
'1.2.840.10008.1.2.1'])
assoc = ae.associate(addr, port)
if assoc.is_established:
dataset = dcmread('file-in.dcm')
# `status` is the response from the peer to the store request
# but may be an empty pydicom Dataset if the peer timed out or
# sent an invalid dataset.
status = assoc.send_c_store(dataset)
assoc.release()