DICOM PS3.3 2024c - Information Object Definitions

C.8.8.27 Beam Limiting Device Position Macro

Table C.8.8.27-1 specifies the Attributes of the Beam Limiting Device Position Macro, which specify the Beam Limiting Device Sequence.

Table C.8.8.27-1. Beam Limiting Device Position Macro Attributes

Attribute Name

Tag

Type

Attribute Description

Beam Limiting Device Position Sequence

(300A,011A)

1C

Sequence of beam limiting device (collimator) jaw or leaf (element) positions.

Required if Ion Beam Limiting Device Sequence (300A,03A4) or Beam Limiting Device Leaf Pairs Sequence (3008,00A0) is included in this SOP Instance and for first Item of the including control point Sequence (either Ion Control Point Sequence (300A,03A8) or Ion Control Point Delivery Sequence (3008,0041)), or if any value of Leaf/Jaw Positions (300A,011C) changes during the Beam.

One or more Items shall be included in this Sequence.

In the first Control Point the number of Items shall be equal to the number of Items of corresponding device definition sequence (Ion Beam Limiting Device Sequence (300A,03A4) or Beam Limiting Device Leaf Pairs Sequence (3008,00A0)).

In subsequent Control Points the Items present shall be only those whose values change during the Beam.

>RT Beam Limiting Device Type

(300A,00B8)

1

Type of beam limiting device (collimator). The value of this Attribute shall correspond to RT Beam Limiting Device Type (300A,00B8) defined in an Item of Ion Beam Limiting Device Sequence (300A,03A4).

Enumerated Values:

X

symmetric jaw pair in IEC X direction

Y

symmetric jaw pair in IEC Y direction

ASYMX

asymmetric jaw pair in IEC X direction

ASYMY

asymmetric jaw pair in IEC Y direction

MLCX

single layer multileaf collimator in IEC X direction

MLCY

single layer multileaf collimator in IEC Y direction

>Leaf/Jaw Positions

(300A,011C)

1

Positions of beam limiting device (collimator) leaf (element) or jaw pairs (in mm) in IEC BEAM LIMITING DEVICE coordinate axis appropriate to RT Beam Limiting Device Type (300A,00B8), e.g., X-axis for MLCX, Y-axis for MLCY. Contains 2N values, where N is the Number of Leaf/Jaw Pairs (300A,00BC) in Ion Beam Limiting Device Sequence (300A,03A4). Values shall be listed in IEC leaf (element) subscript order 101, 102, … 1N, 201, 202, … 2N. See Section C.8.8.25.3.


DICOM PS3.3 2024c - Information Object Definitions