C.8.8.7 RT Dose ROI Module

RT Dose ROI provides ancillary dose-related information to the ROI data defined within the Structure Set and ROI Contour modules, which may be included in the RT Dose IOD composite object. These modules in combination provide for the definition of dose data in the form of isodose curves or named or unnamed dose points. Isodose curves in radiation oncology are simply contours identifying a set of points with the same dose value.

Table C.8-43—RT DOSE ROI MODULE ATTRIBUTES

Attribute Name Tag Type Attribute Description
RT Dose ROI Sequence (3004,0010) 1 Introduces sequence of items specifying dose levels for isodose curves or dose points described in the ROI module. One or more items shall be included in this sequence. See C.8.8.7.1.
>Referenced ROI Number (3006,0084) 1 Uniquely identifies the referenced ROI within the current RT Dose. See Note 1 and C.8.8.7.2.
>Dose Units (3004,0002) 1 Units used for ROI Dose. Enumerated Values: GY = Gray RELATIVE = dose relative to implicit reference value
>Dose Value (3004,0012) 1 Dose value for ROI, in units defined by Dose Units (3004,0002). See C.8.8.7.3.

Notes: 1. The Structure Set ROI Sequence (3006,0020) defining the dose point and surfaces is defined in the Structure Set module. The ROI Number (3006,0022) attribute is unique within the Structure Set ROI Sequence, and is referenced from the RT Dose ROI module using Referenced ROI Number (3006,0084).

2. The RT Dose ROI module defines the attributes that describe references to ROIs contained within the associated Structure Set and RT ROI Contour modules. Note that the RT Dose module table specifies that either all or none of the modules Structures Set, ROI Contour, and RT Dose ROI must be present in the RT Dose IOD.

C.8.8.7.1 Contour Geometric Type of Referenced ROI

ROIs referenced in the RT Dose ROI Module shall have a Contour Geometric Type (3006,0042) of POINT, OPEN_PLANAR or CLOSED_PLANAR.

C.8.8.7.2 Referenced ROI Number

There shall be a one-to-one correspondence between Referenced ROI Number (3006,0084) and the sequence of ROIs defined in the Structure Set and ROI Contour modules. The RT Dose ROI module shall only contain references to structures which are dose-related (i.e. dose points and isodose curves).

C.8.8.7.3 Dose Value

Dose Value (3004,0012) shall be the dose value corresponding to the referenced isodose curve, named dose point, or unnamed dose point.