DICOM PS3.3 2019a - Information Object Definitions

C.34.7 Instructions Module

Table C.34.7-1 contains instructions relating to preparation and performance of the Protocol.

Table C.34.7-1. Instructions Module Attributes

Attribute Name



Attribute Description

Instruction Sequence



Instructions relating to preparation and performance of the Protocol.

See Section C.34.7.1.

One or more Items shall be included in this Sequence.

>Instruction Index



Identifies the order in which instruction Sequence Items are performed.

The value shall be an integer, increasing monotonically by 1, starting from 1.

>Instruction Text



A short displayable string indicating what should be done.

>Instruction Description



A detailed description explaining what should be done.

>Instruction Performed Flag



Whether or not this instruction was followed in the performed Protocol.

Required if the value of SOP Class UID (0008,0016) equals 1.2.840.10008. (CT Performed Procedure Protocol Storage).

Enumerated Values:



>Instruction Performed DateTime



Date and time the instruction was performed.

Required if Instruction Performed Flag (0018,9918) is present with a value of YES.

>Instruction Performance Comment



Comment about how the instruction was actually performed, about the outcome of performing the instruction or about why the instruction was not performed.

C.34.7.1 Instruction Sequence

This Sequence describes instructions to be performed by the scanner staff in conjunction with the Protocol. The instructions are generally limited to activites that happen inside the scan suite and might include

  • preparation of the scanner (e.g., running a particular calibration, mounting a head holder or patient grab handles on the table) ,

  • preparation of the patient (e.g., asking if they have fasted, placing padding or shielding, giving the patient water as oral contrast, turning the patient prone for the second acquisition in a virtual colonoscopy Protocol) ,

  • instructions to the patient during the imaging procedure (e.g., asking the patient to hold their breath, asking the patient to hyperventilate prior to breathold)

  • instructions to the technologist during the imaging procedure (e.g., obtain the spiral acquisition during a single breathhold, take additional images if some condition is true).

The instruction may also include timing or triggering details, for example:

  • Start the Portal Venous phase Acquisition Protocol Element when an ROI placed over the liver detects a contrast bolus at 50 HU above baseline

  • Start the Delay phase Acquisition Protocol Element three minutes after start of contrast injection

  • Start the AP Localizer Acquisition Protocol Element eight minutes after start of contrast injection and repeat the AP Localizer Acquisition Protocol Element at one minute intervals until adequate ureter opacification is observed, then proceed to the abdomen Acquisition Protocol Element

Instructions related to the initial positioning of the patient are included in the Patient Positioning Module. This Module may describe subsequent changes in position between steps of the protocol.

Equipment preparation instructions would typically be limited to phantom imaging or other calibration procedures related to the individual patient scan. Phantom Imaging and/or Calibration to be performed as general QA/qualification (i.e., not associated with the individual patient scan) shall not be described in this Module.

Activities that are associated with the protocol but which are not typically performed in the scanning room, such as the need to obtain creatinine values within 7 days before performing the Protocol, or to premedicate the patient with Benadryl 1 hour before performing the Protocol, are described in the Protocol Planning Information (0018,990F) rather than in this Module.

DICOM PS3.3 2019a - Information Object Definitions