A photo, video, or audio recording acquired or used in healthcare. The actual content may be inline or provided by direct reference.

A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content. Often, this is a reference to an implementation guide that defines the special rules along with other profiles etc.

Asserting this rule set restricts the content to be only understood by a limited set of trading partners. This inherently limits the usefulness of the data in the long term. However, the existing health eco-system is highly fractured, and not yet ready to define, collect, and exchange data in a generally computable sense. Wherever possible, implementers and/or specification writers should avoid using this element. Often, when used, the URL is a reference to an implementation guide that defines these special rules as part of it's narrative along with other profiles, value sets, etc.

An Extension

R5: DocumentReference.version (new:string)

Element DocumentReference.version has a context of Media based on following the parent source element upwards and mapping to Media. Element DocumentReference.version has a context of DocumentReference based on following the parent source element upwards and mapping to DocumentReference. Element DocumentReference.version has no mapping targets in FHIR R4B. Typically, this is because the element has been added (is a new element). While each resource, including the DocumentReference itself, has its own version identifier, this is a formal identifier for the logical version of the DocumentReference as a whole. It would remain constant if the resources were moved to a new server, and all got new individual resource versions, for example.

R5: DocumentReference.attester (new:BackboneElement)

Element DocumentReference.attester has a context of Media based on following the parent source element upwards and mapping to Media. Element DocumentReference.attester has a context of DocumentReference based on following the parent source element upwards and mapping to DocumentReference. Element DocumentReference.attester has no mapping targets in FHIR R4B. Typically, this is because the element has been added (is a new element). Only list each attester once.

May be used to represent additional information that is not part of the basic definition of the resource and that modifies the understanding of the element that contains it and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

The current state of the {{title}}.

A nominal state-transition diagram can be found in the [[event.html#statemachine | Event pattern]] documentation

Unknown does not represent "other" - one of the defined statuses must apply. Unknown is used when the authoring system is not sure what the current status is.

Codes identifying the lifecycle stage of an event.

The actual content of the media - inline or by direct reference to the media source file.

Recommended content types: image/jpeg, image/png, image/tiff, video/mpeg, audio/mp4, application/dicom. Application/dicom can contain the transfer syntax as a parameter. For media that covers a period of time (video/sound), the content.creationTime is the end time. Creation time is used for tracking, organizing versions and searching.

An Extension

R5: DocumentReference.content.profile (new:BackboneElement)

Element DocumentReference.content.profile has a context of Media.content based on following the parent source element upwards and mapping to Media. Element DocumentReference.content.profile has a context of DocumentReference.content based on following the parent source element upwards and mapping to DocumentReference. Element DocumentReference.content.profile has no mapping targets in FHIR R4B. Typically, this is because the element has been added (is a new element). Note that IHE often issues URNs for formatCode codes, not all documents can be identified by a URI.

For FHIR content, .profile should indicate the structureDefinition profile canonical URI(s) that the content complies with.

R5: DocumentReference.version (new:string)

Element DocumentReference.version has a context of Media based on following the parent source element upwards and mapping to Media. Element DocumentReference.version has a context of DocumentReference based on following the parent source element upwards and mapping to DocumentReference. Element DocumentReference.version has no mapping targets in FHIR R4B. Typically, this is because the element has been added (is a new element). While each resource, including the DocumentReference itself, has its own version identifier, this is a formal identifier for the logical version of the DocumentReference as a whole. It would remain constant if the resources were moved to a new server, and all got new individual resource versions, for example.

R5: DocumentReference.attester (new:BackboneElement)

Element DocumentReference.attester has a context of Media based on following the parent source element upwards and mapping to Media. Element DocumentReference.attester has a context of DocumentReference based on following the parent source element upwards and mapping to DocumentReference. Element DocumentReference.attester has no mapping targets in FHIR R4B. Typically, this is because the element has been added (is a new element). Only list each attester once.

R5: DocumentReference.basedOn

Element DocumentReference.basedOn is mapped to FHIR R4B element Media.basedOn as SourceIsBroaderThanTarget. The standard extension alternate-reference has been mapped as the representation of FHIR R5 element DocumentReference.basedOn with unmapped reference targets: Appointment, AppointmentResponse, Claim, CommunicationRequest, Contract, CoverageEligibilityRequest, DeviceRequest, EnrollmentRequest, ImmunizationRecommendation, MedicationRequest, NutritionOrder, RequestOrchestration, SupplyRequest, VisionPrescription.

R5: DocumentReference.subject additional types from child elements (display, identifier, reference, type)

Element DocumentReference.subject is mapped to FHIR R4B element Media.subject as SourceIsBroaderThanTarget. Element DocumentReference.subject is mapped to FHIR R4B element DocumentReference.subject as SourceIsBroaderThanTarget. The mappings for DocumentReference.subject do not cover the following types based on type expansion: display, identifier, reference, type. The standard extension alternate-reference has been mapped as the representation of FHIR R5 element DocumentReference.subject with unmapped reference targets: Resource.

R5: DocumentReference.bodySite additional types (CodeableReference(http://hl7.org/fhir/StructureDefinition/BodyStructure)) additional types from child elements (reference)

Element DocumentReference.bodySite is mapped to FHIR R4B element Media.bodySite as SourceIsBroaderThanTarget. The mappings for DocumentReference.bodySite do not cover the following types: CodeableReference. The mappings for DocumentReference.bodySite do not cover the following types based on type expansion: reference.

R5: DocumentReference.content.profile (new:BackboneElement)

Element DocumentReference.content.profile has a context of Media.content based on following the parent source element upwards and mapping to Media. Element DocumentReference.content.profile has a context of DocumentReference.content based on following the parent source element upwards and mapping to DocumentReference. Element DocumentReference.content.profile has no mapping targets in FHIR R4B. Typically, this is because the element has been added (is a new element). Note that IHE often issues URNs for formatCode codes, not all documents can be identified by a URI.

For FHIR content, .profile should indicate the structureDefinition profile canonical URI(s) that the content complies with.

A photo, video, or audio recording acquired or used in healthcare. The actual content may be inline or provided by direct reference.

The logical id of the resource, as used in the URL for the resource. Once assigned, this value never changes.

The only time that a resource does not have an id is when it is being submitted to the server using a create operation.

The metadata about the resource. This is content that is maintained by the infrastructure. Changes to the content might not always be associated with version changes to the resource.

A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content. Often, this is a reference to an implementation guide that defines the special rules along with other profiles etc.

Asserting this rule set restricts the content to be only understood by a limited set of trading partners. This inherently limits the usefulness of the data in the long term. However, the existing health eco-system is highly fractured, and not yet ready to define, collect, and exchange data in a generally computable sense. Wherever possible, implementers and/or specification writers should avoid using this element. Often, when used, the URL is a reference to an implementation guide that defines these special rules as part of it's narrative along with other profiles, value sets, etc.

The base language in which the resource is written.

Language is provided to support indexing and accessibility (typically, services such as text to speech use the language tag). The html language tag in the narrative applies to the narrative. The language tag on the resource may be used to specify the language of other presentations generated from the data in the resource. Not all the content has to be in the base language. The Resource.language should not be assumed to apply to the narrative automatically. If a language is specified, it should it also be specified on the div element in the html (see rules in HTML5 for information about the relationship between xml:lang and the html lang attribute).

IETF language tag

A human-readable narrative that contains a summary of the resource and can be used to represent the content of the resource to a human. The narrative need not encode all the structured data, but is required to contain sufficient detail to make it "clinically safe" for a human to just read the narrative. Resource definitions may define what content should be represented in the narrative to ensure clinical safety.

Contained resources do not have narrative. Resources that are not contained SHOULD have a narrative. In some cases, a resource may only have text with little or no additional discrete data (as long as all minOccurs=1 elements are satisfied). This may be necessary for data from legacy systems where information is captured as a "text blob" or where text is additionally entered raw or narrated and encoded information is added later.

These resources do not have an independent existence apart from the resource that contains them - they cannot be identified independently, and nor can they have their own independent transaction scope.

This should never be done when the content can be identified properly, as once identification is lost, it is extremely difficult (and context dependent) to restore it again. Contained resources may have profiles and tags In their meta elements, but SHALL NOT have security labels.

An Extension

R5: DocumentReference.version (new:string)

Element DocumentReference.version has a context of Media based on following the parent source element upwards and mapping to Media. Element DocumentReference.version has a context of DocumentReference based on following the parent source element upwards and mapping to DocumentReference. Element DocumentReference.version has no mapping targets in FHIR R4B. Typically, this is because the element has been added (is a new element). While each resource, including the DocumentReference itself, has its own version identifier, this is a formal identifier for the logical version of the DocumentReference as a whole. It would remain constant if the resources were moved to a new server, and all got new individual resource versions, for example.

R5: DocumentReference.attester (new:BackboneElement)

Element DocumentReference.attester has a context of Media based on following the parent source element upwards and mapping to Media. Element DocumentReference.attester has a context of DocumentReference based on following the parent source element upwards and mapping to DocumentReference. Element DocumentReference.attester has no mapping targets in FHIR R4B. Typically, this is because the element has been added (is a new element). Only list each attester once.

May be used to represent additional information that is not part of the basic definition of the resource and that modifies the understanding of the element that contains it and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Identifiers associated with the image - these may include identifiers for the image itself, identifiers for the context of its collection (e.g. series ids) and context ids such as accession numbers or other workflow identifiers.

The identifier label and use can be used to determine what kind of identifier it is.

A procedure that is fulfilled in whole or in part by the creation of this media.

Allows tracing of authorization for the event and tracking whether proposals/recommendations were acted upon.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

An Extension

R5: DocumentReference.basedOn

Element DocumentReference.basedOn is mapped to FHIR R4B element Media.basedOn as SourceIsBroaderThanTarget. The standard extension alternate-reference has been mapped as the representation of FHIR R5 element DocumentReference.basedOn with unmapped reference targets: Appointment, AppointmentResponse, Claim, CommunicationRequest, Contract, CoverageEligibilityRequest, DeviceRequest, EnrollmentRequest, ImmunizationRecommendation, MedicationRequest, NutritionOrder, RequestOrchestration, SupplyRequest, VisionPrescription.

A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries. Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

The expected type of the target of the reference. If both Reference.type and Reference.reference are populated and Reference.reference is a FHIR URL, both SHALL be consistent.

The type is the Canonical URL of Resource Definition that is the type this reference refers to. References are URLs that are relative to http://hl7.org/fhir/StructureDefinition/ e.g. "Patient" is a reference to http://hl7.org/fhir/StructureDefinition/Patient. Absolute URLs are only allowed for logical models (and can only be used in references in logical models, not resources).

This element is used to indicate the type of the target of the reference. This may be used which ever of the other elements are populated (or not). In some cases, the type of the target may be determined by inspection of the reference (e.g. a RESTful URL) or by resolving the target of the reference; if both the type and a reference is provided, the reference SHALL resolve to a resource of the same type as that specified.

An identifier for the target resource. This is used when there is no way to reference the other resource directly, either because the entity it represents is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.

When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference

Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

Reference is intended to point to a structure that can potentially be expressed as a FHIR resource, though there is no need for it to exist as an actual FHIR resource instance - except in as much as an application wishes to actual find the target of the reference. The content referred to be the identifier must meet the logical constraints implied by any limitations on what resource types are permitted for the reference. For example, it would not be legitimate to send the identifier for a drug prescription if the type were Reference(Observation|DiagnosticReport). One of the use-cases for Reference.identifier is the situation where no FHIR representation exists (where the type is Reference (Any).

Plain text narrative that identifies the resource in addition to the resource reference.

This is generally not the same as the Resource.text of the referenced resource. The purpose is to identify what's being referenced, not to fully describe it.

A larger event of which this particular event is a component or step.

Not to be used to link an event to an Encounter - use Media.encounter for that.

[The allowed reference resources may be adjusted as appropriate for the event resource].

E.g. Drug administration as part of a procedure, procedure as part of observation, etc.

The current state of the {{title}}.

A nominal state-transition diagram can be found in the [[event.html#statemachine | Event pattern]] documentation

Unknown does not represent "other" - one of the defined statuses must apply. Unknown is used when the authoring system is not sure what the current status is.

Codes identifying the lifecycle stage of an event.

A code that classifies whether the media is an image, video or audio recording or some other media category.

Codes for high level media categories.

Used for filtering what observations are retrieved and displayed.

Details of the type of the media - usually, how it was acquired (what type of device). If images sourced from a DICOM system, are wrapped in a Media resource, then this is the modality.

Detailed information about the type of the image - its kind, purpose, or the kind of equipment used to generate it.

The name of the imaging view e.g. Lateral or Antero-posterior (AP).

Imaging view (projection) used when collecting an image.

Who/What this Media is a record of.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

An Extension

R5: DocumentReference.subject additional types from child elements (display, identifier, reference, type)

Element DocumentReference.subject is mapped to FHIR R4B element Media.subject as SourceIsBroaderThanTarget. Element DocumentReference.subject is mapped to FHIR R4B element DocumentReference.subject as SourceIsBroaderThanTarget. The mappings for DocumentReference.subject do not cover the following types based on type expansion: display, identifier, reference, type. The standard extension alternate-reference has been mapped as the representation of FHIR R5 element DocumentReference.subject with unmapped reference targets: Resource.

A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries. Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

The expected type of the target of the reference. If both Reference.type and Reference.reference are populated and Reference.reference is a FHIR URL, both SHALL be consistent.

The type is the Canonical URL of Resource Definition that is the type this reference refers to. References are URLs that are relative to http://hl7.org/fhir/StructureDefinition/ e.g. "Patient" is a reference to http://hl7.org/fhir/StructureDefinition/Patient. Absolute URLs are only allowed for logical models (and can only be used in references in logical models, not resources).

This element is used to indicate the type of the target of the reference. This may be used which ever of the other elements are populated (or not). In some cases, the type of the target may be determined by inspection of the reference (e.g. a RESTful URL) or by resolving the target of the reference; if both the type and a reference is provided, the reference SHALL resolve to a resource of the same type as that specified.

An identifier for the target resource. This is used when there is no way to reference the other resource directly, either because the entity it represents is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.

When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference

Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

Reference is intended to point to a structure that can potentially be expressed as a FHIR resource, though there is no need for it to exist as an actual FHIR resource instance - except in as much as an application wishes to actual find the target of the reference. The content referred to be the identifier must meet the logical constraints implied by any limitations on what resource types are permitted for the reference. For example, it would not be legitimate to send the identifier for a drug prescription if the type were Reference(Observation|DiagnosticReport). One of the use-cases for Reference.identifier is the situation where no FHIR representation exists (where the type is Reference (Any).

Plain text narrative that identifies the resource in addition to the resource reference.

This is generally not the same as the Resource.text of the referenced resource. The purpose is to identify what's being referenced, not to fully describe it.

The encounter that establishes the context for this media.

This will typically be the encounter the media occurred within.

Links the Media to the Encounter context.

The date and time(s) at which the media was collected.

The date and time this version of the media was made available to providers, typically after having been reviewed.

It may be the same as the lastUpdated time of the resource itself. For Observations that do require review and verification for certain updates, it might not be the same as the lastUpdated time of the resource itself due to a non-clinically significant update that does not require the new version to be reviewed and verified again.

The person who administered the collection of the image.

Describes why the event occurred in coded or textual form.

Textual reasons can be captured using reasonCode.text.

The reason for the media.

Indicates the site on the subject's body where the observation was made (i.e. the target site).

Only used if not implicit in code found in Observation.code. In many systems, this may be represented as a related observation instead of an inline component.

If the use case requires BodySite to be handled as a separate resource (e.g. to identify and track separately) then use the standard extension bodySite.

SNOMED CT Body site concepts

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

An Extension

R5: DocumentReference.bodySite additional types (CodeableReference(http://hl7.org/fhir/StructureDefinition/BodyStructure)) additional types from child elements (reference)

Element DocumentReference.bodySite is mapped to FHIR R4B element Media.bodySite as SourceIsBroaderThanTarget. The mappings for DocumentReference.bodySite do not cover the following types: CodeableReference. The mappings for DocumentReference.bodySite do not cover the following types based on type expansion: reference.

A reference to a code defined by a terminology system.

Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

Allows for alternative encodings within a code system, and translations to other code systems.

A human language representation of the concept as seen/selected/uttered by the user who entered the data and/or which represents the intended meaning of the user.

Very often the text is the same as a displayName of one of the codings.

The codes from the terminologies do not always capture the correct meaning with all the nuances of the human using them, or sometimes there is no appropriate code at all. In these cases, the text is used to capture the full meaning of the source.

The name of the device / manufacturer of the device that was used to make the recording.

The device used to collect the media.

An extension should be used if further typing of the device is needed. Secondary devices used to support collecting a media can be represented using either extension or through the Observation.related element.

Height of the image in pixels (photo/video).

Width of the image in pixels (photo/video).

The number of frames in a photo. This is used with a multi-page fax, or an imaging acquisition context that takes multiple slices in a single image, or an animated gif. If there is more than one frame, this SHALL have a value in order to alert interface software that a multi-frame capable rendering widget is required.

if the number of frames is not supplied, the value may be unknown. Applications should not assume that there is only one frame unless it is explicitly stated.

The duration of the recording in seconds - for audio and video.

The duration might differ from occurrencePeriod if recording was paused.

The actual content of the media - inline or by direct reference to the media source file.

Recommended content types: image/jpeg, image/png, image/tiff, video/mpeg, audio/mp4, application/dicom. Application/dicom can contain the transfer syntax as a parameter. For media that covers a period of time (video/sound), the content.creationTime is the end time. Creation time is used for tracking, organizing versions and searching.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

An Extension

R5: DocumentReference.content.profile (new:BackboneElement)

Element DocumentReference.content.profile has a context of Media.content based on following the parent source element upwards and mapping to Media. Element DocumentReference.content.profile has a context of DocumentReference.content based on following the parent source element upwards and mapping to DocumentReference. Element DocumentReference.content.profile has no mapping targets in FHIR R4B. Typically, this is because the element has been added (is a new element). Note that IHE often issues URNs for formatCode codes, not all documents can be identified by a URI.

For FHIR content, .profile should indicate the structureDefinition profile canonical URI(s) that the content complies with.

Identifies the type of the data in the attachment and allows a method to be chosen to interpret or render the data. Includes mime type parameters such as charset where appropriate.

BCP 13 (RFCs 2045, 2046, 2047, 4288, 4289 and 2049)

Processors of the data need to be able to know how to interpret the data.

The human language of the content. The value can be any valid value according to BCP 47.

IETF language tag

Users need to be able to choose between the languages in a set of attachments.

The actual data of the attachment - a sequence of bytes, base64 encoded.

The base64-encoded data SHALL be expressed in the same character set as the base resource XML or JSON.

The data needs to able to be transmitted inline.

A location where the data can be accessed.

If both data and url are provided, the url SHALL point to the same content as the data contains. Urls may be relative references or may reference transient locations such as a wrapping envelope using cid: though this has ramifications for using signatures. Relative URLs are interpreted relative to the service url, like a resource reference, rather than relative to the resource itself. If a URL is provided, it SHALL resolve to actual data.

The data needs to be transmitted by reference.

The number of bytes of data that make up this attachment (before base64 encoding, if that is done).

The number of bytes is redundant if the data is provided as a base64binary, but is useful if the data is provided as a url reference.

Representing the size allows applications to determine whether they should fetch the content automatically in advance, or refuse to fetch it at all.

The calculated hash of the data using SHA-1. Represented using base64.

The hash is calculated on the data prior to base64 encoding, if the data is based64 encoded. The hash is not intended to support digital signatures. Where protection against malicious threats a digital signature should be considered, see Provenance.signature for mechanism to protect a resource with a digital signature.

Included so that applications can verify that the contents of a location have not changed due to technical failures (e.g., storage rot, transport glitch, incorrect version).

A label or set of text to display in place of the data.

Applications need a label to display to a human user in place of the actual data if the data cannot be rendered or perceived by the viewer.

The date that the attachment was first created.

This is often tracked as an integrity issue for use of the attachment.

Comments made about the media by the performer, subject or other participants.

Not to be used for observations, conclusions, etc. Instead use an Observation based on the Media/ImagingStudy resource.