Acquisition Protocol Element Specification Sequence Attribute
| Tag | (0018,991F) |
|---|---|
| Type | Required (1) |
| Keyword | AcquisitionProtocolElementSpecificationSequence |
| Value Multiplicity | 1 |
| Value Representation | Sequence (SQ) |
Specification of the acquisition parameters for acquisition protocol elements in an imaging procedure.
There shall be one Item in this Sequence for each Acquisition Protocol Element in the Protocol. See Section C.34.9.1.
One or more Items shall be included in this Sequence.
Section C.34.9.1
C.34.9.1 Acquisition Protocol Elements
A Protocol usually includes more than one Acquisition Protocol Element. For example, a chest Protocol in CT might include three elements in total: two localizer CT radiographs (AP and Lateral), and a single helical scan.
An illustrative example for CT is provided in Table C.34.9-2. In this example, since all parameters will be nested inside an Acquisition Protocol Element Sequence (0018,9920) and some of the parameters will be further nested inside a CT X-Ray Details Sequence (0018,9325), close attention must be paid to the use of the Selector Sequence Pointer (0072,0052) in the Attribute Value Constraint Macro.
Table C.34.9-2. Example Usage of Selector Macro Attributes for Acquisition Constraints
|
Example |
Selector Attribute (0072,0026) |
Selector Value Number (0072,0028) |
Selector Sequence Pointer (0072,0052) |
Selector Sequence Pointer Items (0074,1057) |
Example Constraint |
|---|---|---|---|---|---|
|
Constrain the value of Element Name (0018,9922) of the first Item in the Acquisition Protocol Element Sequence (0018,9920) |
(0018,9922) |
1 |
(0018,9920) |
1 |
EQUAL"Localizer (AP) " |
|
Constrain the value of Table Speed (0018,9309) of the second Item in the Acquisition Protocol Element Sequence (0018,9920) |
(0018,9309) |
1 |
(0018,9920) |
2 |
EQUAL14 mm/sec |
|
Constrain the value of KVP (0018,0060) of the first beam in the CT X-Ray Details Sequence (0018,9325) of the second Item in the Acquisition Protocol Element Sequence (0018,9920) |
(0018,0060) |
1 |
(0018,9920), (0018,9325) |
2\1 |
RANGE_INCL(120,140) |
|
Constrain the first and second value of Exposure Modulation Type (0018,9323) of the second beam in the CT X-Ray Details Sequence (0018,9325) of the third Item in the Acquisition Protocol Element Sequence (0018,9920) |
(0018,9323) |
1 |
(0018,9920), (0018,9325) |
3\2 |
EQUAL"ANGULAR" |
|
(0018,9323) |
2 |
(0018,9920), (0018,9325) |
3\2 |
EQUAL"ORGAN_BASED" |