Computed Radiography ImageCIOD
Nuclear Medicine ImageCIOD
Ultrasound ImageCIOD
Ultrasound Multi-frame ImageCIOD
Secondary Capture ImageCIOD
Multi-frame Single Bit Secondary Capture ImageCIOD
Multi-frame Grayscale Byte Secondary Capture ImageCIOD
Multi-frame Grayscale Word Secondary Capture ImageCIOD
Multi-frame True Color Secondary Capture ImageCIOD
X-Ray Angiographic ImageCIOD
X-Ray Radiofluoroscopic ImageCIOD
RT Structure SetCIOD
Positron Emission Tomography ImageCIOD
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
Real-Time Video Endoscopic ImageCIOD
Real-Time Video Photographic ImageCIOD
Dermoscopic Photography 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
Variable Modality LUT Softcopy Presentation StateCIOD
Basic Voice Audio WaveformCIOD
Ambulatory ECGCIOD
Hemodynamic WaveformCIOD
Basic Cardiac Electrophysiology WaveformCIOD
Arterial Pulse WaveformCIOD
Respiratory WaveformCIOD
General Audio WaveformCIOD
Real-Time Audio WaveformCIOD
Routine Scalp ElectroencephalogramCIOD
Sleep ElectroencephalogramCIOD
Multi-channel Respiratory WaveformCIOD
Body Position WaveformCIOD
General 32-bit ECGCIOD
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 SRCIOD
Planned Imaging Agent Administration SRCIOD
Performed Imaging Agent Administration SRCIOD
Rendition Selection DocumentCIOD
Enhanced X-Ray Radiation Dose SRCIOD
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 XA ImageCIOD
Enhanced XRF 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 Optical Coherence Tomography 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
CT Performed Procedure ProtocolCIOD
CT Defined Procedure ProtocolCIOD
Protocol ApprovalCIOD
XA Performed Procedure ProtocolCIOD
XA Defined Procedure ProtocolCIOD
Ophthalmic Optical Coherence Tomography En Face ImageCIOD
Ophthalmic Optical Coherence Tomography B-scan Volume AnalysisCIOD
Encapsulated STLCIOD
Encapsulated OBJCIOD
Encapsulated MTLCIOD
RT Physician IntentCIOD
RT Segment AnnotationCIOD
RT Radiation SetCIOD
C-Arm Photon-Electron RadiationCIOD
Tomotherapeutic RadiationCIOD
Robotic-Arm RadiationCIOD
RT Radiation Record SetCIOD
RT Radiation Salvage RecordCIOD
C-Arm Photon-Electron Radiation RecordCIOD
Tomotherapeutic Radiation RecordCIOD
Robotic-Arm Radiation RecordCIOD
RT Radiation Set Delivery InstructionCIOD
RT Treatment PreparationCIOD
Enhanced RT ImageCIOD
Enhanced Continuous RT ImageCIOD
RT Patient Position Acquisition InstructionCIOD
Microscopy Bulk Simple AnnotationsCIOD
Photoacoustic ImageCIOD
Confocal Microscopy ImageCIOD
PatientMModule - Patient
Clinical Trial SubjectUModule - Patient
General StudyMModule - Study
Patient StudyUModule - Study
Clinical Trial StudyUModule - Study
General SeriesMModule - Series
Clinical Trial SeriesUModule - Series
Frame of ReferenceMModule - Frame of Reference
SynchronizationCModule - Frame of Reference
General EquipmentMModule - Equipment
Enhanced General EquipmentMModule - Equipment
General AcquisitionMModule - Acquisition
General ImageMModule - Image
General ReferenceUModule - Image
Image PixelMModule - Image
Multi-frame Functional GroupsMModule - Image
(0008,0023) Content Date1Date
(0008,0033) Content Time1Time
(0020,0013) Instance Number1Integer String
(0020,0242) SOP Instance UID of Concatenation Source1CUnique Identifier
(0020,9161) Concatenation UID1CUnique Identifier
(0020,9162) In-concatenation Number1CUnsigned Short
(0020,9163) In-concatenation Total Number3Unsigned Short
(0020,9228) Concatenation Frame Offset Number1CUnsigned Long
(0022,0028) Stereo Pairs Present3Code String
(0028,0008) Number of Frames1Integer String
(0028,6010) Representative Frame Number3Unsigned Short
(5200,9229) Shared Functional Groups Sequence1Sequence
(5200,9230) Per-Frame Functional Groups Sequence1CSequence
(0008,1140) Referenced Image Sequence2Sequence
(0008,9124) Derivation Image Sequence2Sequence
(0020,9071) Frame Anatomy Sequence1Sequence
(0020,9111) Frame Content Sequence1Sequence
(0018,9074) Frame Acquisition DateTime1CDate Time
(0018,9151) Frame Reference DateTime1CDate Time
(0018,9214) Respiratory Cycle Position3Code String
(0018,9220) Frame Acquisition Duration1CDouble
(0018,9236) Cardiac Cycle Position3Code String
(0020,9056) Stack ID1CShort String
(0020,9057) In-Stack Position Number1CUnsigned Long
(0020,9128) Temporal Position Index1CUnsigned Long
(0020,9156) Frame Acquisition Number3Unsigned Short
(0020,9157) Dimension Index Values1CUnsigned Long
(0020,9158) Frame Comments3Long Text
(0020,9453) Frame Label3Long String
(0028,9110) Pixel Measures Sequence1Sequence
(0040,9096) Real World Value Mapping Sequence1Sequence
(0048,0116) Confocal Microscopy Image Frame Type Sequence1Sequence
(0048,0207) Optical Path Identification Sequence1Sequence
(0048,021A) Plane Position (Slide) Sequence1Sequence
(7FE0,0003) Encapsulated Pixel Data Value Total Length3UV
Multi-frame DimensionMModule - Image
SpecimenCModule - Image
Acquisition ContextMModule - Image
Confocal Microscopy ImageMModule - Image
Cutaneous Confocal Microscopy Image Acquisition ParametersCModule - Image
Optical PathMModule - Image
SOP CommonMModule - Image
Common Instance ReferenceUModule - Image
Frame ExtractionCModule - Image
Confocal Microscopy Tiled Pyramidal ImageCIOD
Basic DirectoryCIOD

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

Data synced with official DICOM standard on 18 April 2024. The DICOM Standard is under continuous maintenance, and the current official version is available at DICOM Parts 3, 4, 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.

Frame Reference DateTime Attribute

TypeConditionally Required (1C)
Value Multiplicity1
Value RepresentationDate Time (DT)

The point in time that is most representative of when data was acquired for this frame. See Section C. and Section C. for further explanation.


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

Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL, and Dimension Organization Type (0020,9311) is not TILED_FULL, and the SOP Class UID is not:

  • "1.2.840.10008. (Legacy Converted Enhanced CT Image Storage)", or

  • "1.2.840.10008." (Legacy Converted Enhanced MR Image Storage), or

  • "1.2.840.10008." (Legacy Converted Enhanced PET Image Storage), or

  • "1.2.840.10008." (VL Whole Slide Microscopy Image Storage)

May be present otherwise.


Part of the Frame Content Functional Group Macro with usage: U

Section C.

C. Timing Parameter Relationships

Figure C.7.6.16-2 shows the relationships among the various timing parameters used.

Figure C.7.6.16-2. Relationship of Timing Related Attributes

Section C.

C. Frame Reference DateTime

The Frame Reference DateTime (0018,9151) is used to indicate the point in time that is most representative for that specific frame.


  1. For example, in the case of MR it might be the time of acquisition of the data for the ky = 0 line in k-space (the central Fourier segment).

  2. For cardiac gated acquisitions the choice of the Frame Reference DateTime (0018,9151) is influenced by the Nominal Cardiac Trigger Delay Time (0020,9153). For respiratory gated acquisitions the choice of the Frame Reference DateTime (0018,9151) is influenced by the Nominal Respiratory Trigger Delay Time (0020,9255).

Synchronization Module

C.7.4.2 Synchronization Module

Table C.7-7 specifies the Attributes of the Synchronization Module, which are 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 Module 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.

For IODs that include the RT Radiation Record Common Module, the Acquisition Time Synchronized (0018,1800) Attribute specifies whether the following Attributes represent a synchronized timestamp.

  • Recorded RT Control Point DateTime (300A,073A)

  • Interlock DateTime (300A,0741)