DICOM PS3.18 2019a - Web Services

8 Parameters of the WADO-URI Request

8.1 Parameters Available for all DICOM Objects

Parameters specified in this section are applicable to all supported DICOM SOP Classes.

Some of the Query Parameters specified in this section have values that are UIDs. Table 8.1-1 lists error status codes related to UIDs.

Table 8.1-1. UID Related Errors

Status Code

Reason

400 (Bad Request)

The UID is not a correctly formatted, or it references a resource that is not a SOP Instance (i.e., references an instance of a different entity, e.g., a Study).

404 (Not Found)

No resource corresponding to the UID exists.

410 (Gone)

The resource corresponding to the UID, once existed, but no longer exists.


Note

An origin server that does not check the format of the UID, or does not maintain a history of removed resources, may return a 404 (Not Found).

An error response may include a payload containing an appropriate error message.

Note

To identify a DICOM Object, only one UID is required, because any UID is globally unique. However, the Standard requires that the UID of the higher levels in the DICOM Information Model are specified (i.e., series and study), in order to support the use of DICOM devices that support only the baseline hierarchical (rather than extended relational) Query/Retrieve model, which requires the Study Instance UID and Series Instance UID to be defined when retrieving an SOP Instance, as defined in PS3.4.

8.1.1 Request Type

This parameter specifies that this is a URI service request. The parameter name shall be "requestType", and the value shall be "WADO". It is REQUIRED.

If the value is other than "WADO", and the origin server does not support the value, the response shall be 400 (Bad Request), and may include a payload containing an appropriate error message.

8.1.2 Unique Identifier of the Study

Study Instance UID as defined in PS3.3. This parameter is REQUIRED.

The parameter name shall be "studyUID" for URI mode.

The value shall be encoded as a Unique Identifier (UID) string, as specified in PS3.5, except that it shall not be padded to an even length with a NULL character.

Error status codes related to UIDs are specified in Table 8.1-1.

8.1.3 Unique Identifier of the Series

Series Instance UID as defined in PS3.3. This parameter is REQUIRED.

The parameter name shall be "seriesUID" for URI mode.

The value shall be encoded as a Unique Identifier (UID) string, as specified in PS3.5, except that it shall not be padded to an even length with a NULL character.

Error status codes related to UIDs are specified in Table 8.1-1.

8.1.4 Unique Identifier of the Object

SOP Instance UID as defined in PS3.3. This parameter is REQUIRED.

The parameter name shall be "objectUID" for URI mode.

The value shall be encoded as a unique identifier (UID) string, as specified in PS3.5, except that it shall not be padded to an even length with a NULL character.

Error status codes related to UIDs are specified in Table 8.1-1.

8.1.5 Acceptable Media Type of the Response

This parameter contains one or more Acceptable Media Types as defined in Section 6.1.1.4. This parameter is OPTIONAL for URI mode.

In URI mode the parameter name shall be "contentType", and its value shall contain one or more media types.

See Section 6.1.1 for details.

8.1.6 Acceptable Character Sets

Character set with which the returned objects are to be encoded, as defined in the [RFC7230]. This parameter is OPTIONAL for URI mode.

The parameter name shall be "charset" for URI mode.

See Section 6.1.2 for details.

8.1.7 Anonymize Object

Removal of all patient identification information from within the DICOM Objects, if not already done, as defined in PS3.15. This parameter is OPTIONAL. For the URI mode, it shall only be present if contentType is application/dicom.

The parameter name shall be "anonymize" for URI mode.

The value shall be "yes".

The Server may return an error if it either cannot or refuses to anonymize these objects.

The Server shall return a new SOP Instance UID if the content of the object has not already been anonymized.

If this parameter has any other value than "yes", the origin server shall return a 400 (Bad Request) response, and may include a payload containing an appropriate error message.

Note

  1. This Standard does not introduce any security-related requirements. It is likely that the information contained within DICOM Objects identifies the patient. The protocol used (that is HTTP) can be replaced by HTTPs, which is its secure extension, to protect the information in transit. The underlying DICOM implementation decides whether or not to grant access to a particular DICOM object based on whatever security policy or mechanism it has in place. A server is unlikely to fulfill a request from an unknown user (e.g., accessed via the HTTP protocol) unless it is certain that the data requested has no patient identifying information within it and has been approved for public viewing.

  2. The Anonymize object enables, for example, teaching files systems or clinical trial applications to offer an access to original images stored in a PACS, without disclosing the patient's identity, and requiring storage of a (de-identified) copy of the original image. Anonymization is the responsibility of the Server. In order to preserve patient confidentiality, the Server likely will refuse to deliver an anonymized SOP instance to an unknown or unauthorized person unless the Server is certain that the SOP instance holds no patient identifying information. This would include "blanking out" any annotation area(s) containing nominative information burned into the pixels or in the overlays.

8.1.9 Retired

See PS3.18-2017b.

DICOM PS3.18 2019a - Web Services