DICOM PS3.18 2016a - Web Services

8 Parameters of the Request
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# 8 Parameters of the Request

## 8.1 Parameters Available for all DICOM Persistent Objects

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

### 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

Type of request performed. This parameter is REQUIRED for URI based mode.

The parameter name shall be "requestType".

The value shall be "WADO".

### Note

This parameter allows other types of requests to be introduced in the future, using a similar syntax.

### 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 based mode, and "StudyRequest" that contains a required "studyInstanceUID" attribute for the WS 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.

### 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 based mode, and, for the WS mode, one or multiple "SeriesRequest" that is included into the above described "StudyRequest" and that contains a required "seriesInstanceUID" attribute.

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.

### 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 based mode, and for the WS mode one or multiple "DocumentRequest" that is included into the above described "SeriesRequest" and that include each one:

- a required "DocumentUniqueId" that contains the Instance UID,

- an optional "RepositoryUniqueId" that contains the UID of the DICOM server, and

- an optional "HomeCommunityId" that contains the UID of the "clinical affinity domain".

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.

### 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. It shall be present for the WS mode "Rendered Requester" action, and shall not be present in the other WS mode transactions.

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

In WS mode the parameter name shall be "ContentTypeList", which shall contain one or more "ContentType" elements, each containing a media type.

See Section 6.1.1 for details.

### 8.1.6 Charset of the Response

Character set with which the returned objects are to be encoded, as defined in the [RFC 7230]. This parameter is OPTIONAL for URI based mode, and for the WS mode "Rendered Requester" and shall not be present in the other WS mode transactions.

The parameter name shall be "charset" for URI mode, and "CharsetList" containing one or more "Charset" elements for WS 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. In the URI based mode, it shall only be present if contentType is application/dicom.

This parameter is Optional

The parameter name shall be "anonymize" for URI based mode, and "Anonymize" for the WS mode.

The value shall be "yes".

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

In WS mode, the metadata describing the objects or information extracted from them in the response shall be anonymized if requested.

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

### 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 patients 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 Retrieve Partial Information From Objects

Retrieval of additional information from the DICOM objects, using a filtering mechanism based on the XML mapping of DICOM IODs, as described in the Native DICOM Model defined in PS3.19. This parameter is defined only for the WS mode "Information Requester" transaction.

The parameter name shall be "XPath".

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DICOM PS3.18 2016a - Web Services