PatientMModule - Patient
Clinical Trial SubjectUModule - Patient
General StudyMModule - Study
Patient StudyUModule - Study
Clinical Trial StudyUModule - Study
General SeriesMModule - Series
CR SeriesMModule - Series
Clinical Trial SeriesUModule - Series
General EquipmentMModule - Equipment
General ImageMModule - Image
(0020,0013) Instance Number2Integer String
(0020,0020) Patient Orientation2CCode String
(0008,0023) Content Date2CDate
(0008,0033) Content Time2CTime
(0008,0008) Image Type3Code String
(0020,0012) Acquisition Number3Integer String
(0008,0022) Acquisition Date3Date
(0008,0032) Acquisition Time3Time
(0008,002A) Acquisition DateTime3Date Time
(0020,1002) Images in Acquisition3Integer String
(0020,4000) Image Comments3Long Text
(0028,0300) Quality Control Image3Code String
(0028,0301) Burned In Annotation3Code String
(0028,0302) Recognizable Visual Features3Code String
(0028,2110) Lossy Image Compression3Code String
(0028,2112) Lossy Image Compression Ratio3Decimal String
(0028,2114) Lossy Image Compression Method3Code String
(0088,0200) Icon Image Sequence3Sequence
(2050,0020) Presentation LUT Shape3Code String
(0008,3010) Irradiation Event UID3Unique Identifier
(0040,9096) Real World Value Mapping Sequence3Sequence
General ReferenceUModule - Image
Image PixelMModule - Image
Contrast/BolusCModule - Image
Display ShutterUModule - Image
DeviceUModule - Image
SpecimenUModule - Image
CR ImageMModule - Image
Overlay PlaneUModule - Image
Modality LUTUModule - Image
VOI LUTUModule - Image
SOP CommonMModule - Image
Common Instance ReferenceUModule - Image
US Multi-frame ImageCIOD
Multi-frame Single Bit SC ImageCIOD
Multi-frame Grayscale Byte SC ImageCIOD
Multi-frame Grayscale Word SC ImageCIOD
Multi-frame True Color SC ImageCIOD
X-Ray Angiographic ImageCIOD
RT Structure SetCIOD
Digital X-Ray ImageCIOD
Digital Mammography X-Ray ImageCIOD
Digital Intra-Oral X-Ray ImageCIOD
RT Beams Treatment RecordCIOD
RT Brachy Treatment RecordCIOD
RT Treatment Summary RecordCIOD
VL Endoscopic ImageCIOD
VL Microscopic ImageCIOD
VL Slide-Coordinates Microscopic ImageCIOD
VL Photographic ImageCIOD
Video Endoscopic ImageCIOD
Video Microscopic ImageCIOD
Video Photographic ImageCIOD
VL Whole Slide Microscopy ImageCIOD
Grayscale Softcopy Presentation StateCIOD
Color Softcopy Presentation StateCIOD
Pseudo-Color Softcopy Presentation StateCIOD
Blending Softcopy Presentation StateCIOD
Basic Structured DisplayCIOD
XA/XRF Grayscale Softcopy Presentation StateCIOD
Advanced Blending Presentation StateCIOD
Basic Voice AudioCIOD
Ambulatory ECGCIOD
Basic Cardiac EPCIOD
Arterial Pulse WaveformCIOD
Respiratory WaveformCIOD
General Audio WaveformCIOD
Basic Text SRCIOD
Enhanced SRCIOD
Comprehensive SRCIOD
Key Object Selection DocumentCIOD
Mammography CAD SRCIOD
Procedure LogCIOD
X-Ray Radiation Dose SRCIOD
Spectacle Prescription ReportCIOD
Macular Grid Thickness and Volume ReportCIOD
Implantation Plan SR DocumentCIOD
Comprehensive 3D SRCIOD
Radiopharmaceutical Radiation Dose SRCIOD
Extensible SRCIOD
Acquisition Context SRCIOD
Simplified Adult Echo SRCIOD
Patient Radiation Dose Structured ReportCIOD
Enhanced MR ImageCIOD
MR SpectroscopyCIOD
Enhanced MR Color ImageCIOD
Raw DataCIOD
Enhanced CT ImageCIOD
Spatial RegistrationCIOD
Deformable Spatial RegistrationCIOD
Spatial FiducialsCIOD
Ophthalmic Photography 8 Bit ImageCIOD
Ophthalmic Photography 16 Bit ImageCIOD
Stereometric RelationshipCIOD
Hanging ProtocolCIOD
Encapsulated PDFCIOD
Encapsulated CDACIOD
Real World Value MappingCIOD
Enhanced X-Ray Angiographic ImageCIOD
Enhanced X-Ray RF ImageCIOD
RT Ion Beams Treatment RecordCIOD
Ophthalmic Tomography ImageCIOD
X-Ray 3D Angiographic ImageCIOD
X-Ray 3D Craniofacial ImageCIOD
Breast Tomosynthesis ImageCIOD
Enhanced PET ImageCIOD
Surface SegmentationCIOD
Color PaletteCIOD
Enhanced US VolumeCIOD
Lensometry MeasurementsCIOD
Autorefraction MeasurementsCIOD
Keratometry MeasurementsCIOD
Subjective Refraction MeasurementsCIOD
Visual Acuity MeasurementsCIOD
Ophthalmic Axial MeasurementsCIOD
Intraocular Lens CalculationsCIOD
Generic Implant TemplateCIOD
Implant Assembly TemplateCIOD
Implant Template GroupCIOD
RT Beams Delivery InstructionCIOD
Ophthalmic Visual Field Static Perimetry MeasurementsCIOD
Intravascular OCT ImageCIOD
Ophthalmic Thickness MapCIOD
Surface Scan MeshCIOD
Surface Scan Point CloudCIOD
Legacy Converted Enhanced CT ImageCIOD
Legacy Converted Enhanced MR ImageCIOD
Legacy Converted Enhanced PET ImageCIOD
Corneal Topography MapCIOD
Breast Projection X-Ray ImageCIOD
Parametric MapCIOD
Wide Field Ophthalmic Photography Stereographic Projection ImageCIOD
Wide Field Ophthalmic Photography 3D Coordinates ImageCIOD
Tractography ResultsCIOD
RT Brachy Application Setup Delivery InstructionCIOD
Planar MPR Volumetric Presentation StateCIOD
Volume Rendering Volumetric Presentation StateCIOD
Content Assessment ResultsCIOD
Table CT Performed Procedure ProtocolCIOD
CT Defined Procedure ProtocolCIOD
Protocol ApprovalCIOD
Ophthalmic Optical Coherence Tomography En Face ImageCIOD
Ophthalmic Optical Coherence Tomography B-scan Volume AnalysisCIOD

Built with by Innolitics, a team of medical imaging software developers.

Data synced with official DICOM standard on 25 September 2017. The DICOM Standard is under continuous maintenance, and the current official version is available at DICOM Parts 3 and 6, © NEMA. Please note that the most recent PDF version of the standard is the official reference, and should checked when making technical decisions.

Acquisition DateTime Attribute

TypeOptional (3)
Value Multiplicity1
Value RepresentationDate Time (DT)

The date and time that the acquisition of data that resulted in this image started.


The synchronization of this time with an external clock is specified in the Synchronization Module in Acquisition Time Synchronized (0018,1800).

Synchronization Module

C.7.4.2 Synchronization Module

Table C.7-7 specifies the Attributes necessary to uniquely identify a frame of reference that establishes the temporal relationship of SOP Instances. A synchronized environment may be established based on a shared time of day clock, and/or on a shared trigger event or synchronization waveform channel.


Within a synchronized environment, different devices may use the shared data differently. An electrical pulse, for example, may be treated as a trigger event by one device (e.g., an x-ray imaging system), but may be recorded as a synchronization waveform by another device (e.g., a hemodynamics system).

Table C.7-7. Synchronization Module Attributes

Attribute Name



Attribute Description

Synchronization Frame of Reference UID



UID of common synchronization environment. See Section C.

Synchronization Trigger



Data acquisition synchronization with external equipment

Enumerated Values:


this equipment provides synchronization channel or trigger to other equipment


this equipment receives synchronization channel or trigger from other equipment


this equipment receives synchronization channel or trigger and forwards it


data acquisition not synchronized by common channel or trigger

Trigger Source or Type



Specifies equipment ID of trigger source and/or type of trigger

Synchronization Channel



Identifier of waveform channel that records the synchronization channel or trigger, see Section C.

Required if synchronization channel or trigger is encoded in a waveform in this SOP Instance

Acquisition Time Synchronized



Acquisition DateTime (0008,002A) synchronized with external time reference.

Enumerated Values:



See Section C.

Time Source



ID of equipment or system providing time reference

Time Distribution Protocol



Method of time distribution used to synchronize this equipment.

Enumerated Values:


Network Time Protocol


Inter Range Instrumentation Group


Global Positioning System


Simple Network Time Protocol


IEEE 1588 Precision Time Protocol

NTP Source Address



IP Address of NTP, SNTP, or PTP time source. IPv4 addresses shall be in dotted decimal (e.g., The IPv6 addresses shall be in colon separated hexadecimal (e.g., 12:34:56:78:9a:bc:de:f0).


Identity of this value in two instances acquired contemporaneously implies a common time base. The NTP Source Address might not persist over time.

C. Synchronization Attribute Descriptions
C. Synchronization Frame of Reference UID

A set of equipment may share a common acquisition synchronization environment, which is identified by a Synchronization Frame of Reference UID. All SOP Instances that share the same Synchronization Frame of Reference UID shall be temporally related to each other. If a Synchronization Frame of Reference UID is present, all SOP Instances in the Series must share the same Frame of Reference.

The UTC Synchronization UID, 1.2.840.10008.15.1.1, may be used when the equipment is synchronized to the international standard UTC. In this case the quality of synchronization may be determined by means of the Time Distribution Protocol (0018,1802) and NTP Source Address (0018,1803).


  1. The Synchronization Frame of Reference UID defines an equipment synchronization environment, and does not need to be changed for each unrelated acquisition. SOP Instances may therefore share a Synchronization Frame of Reference UID, but be clinically unrelated (e.g., apply to different patients).

  2. When a synchronization environment is recalibrated, a new UID must be issued.

  3. The method of distributing the Synchronization Frame of Reference UID to multiple devices is not specified.

C. Time Source and Time Distribution Protocol

Time may originate with a primary source (e.g., a national standards bureau) and be distributed through a chain of secondary distribution systems until reaching the imaging equipment. Time Distribution Protocol (0018,1802) specifies the immediate (last link) method used by the equipment to receive time from the immediately prior Time Source (0018,1801). It does not specify the ultimate time reference from which the Time Source may derive its synchronization.


The time value distributed through the specified Time Distribution Protocol may need to be corrected to align with UTC. For example, GPS does not compensate for leap seconds.

C. Synchronization Channel

Synchronization Channel (0018,106C) is specified as a pair of values (M,C), where the first value is the ordinal of the sequence item of Waveform Sequence (5400,0100) (i.e., the Multiplex Group), and the second value is the ordinal of the sequence item of the Channel Definition Sequence (003A,0200) attribute (i.e., the Waveform Channel Number) within the multiplex group.

C. Acquisition Time Synchronized

The Acquisition Time Synchronized (0018,1800) attribute specifies whether Acquisition DateTime (0008,002A) of the Waveform Identification Module or the General Image Module represents an accurate synchronized timestamp for the acquisition of the waveform and/or image data. For triggered multi-frame images, the Acquisition DateTime applies to the trigger for the first image frame (see attribute Image Trigger Delay (0018.1067) in the Cine Module).


The degree of precision of the Acquisition DateTime and its accuracy relative to the external clock are not specified, but need to be appropriate for the clinical application.

For IODs that include the SR Document Content Module, the Acquisition Time Synchronized (0018,1800) attribute specifies whether Observation DateTime (0040,A032) of Items in Content Sequence (0040,A730) of the SR Document Content Module represents an accurate synchronized timestamp for the Item.