DICOM PS3.3 2020a - Information Object Definitions

C.36.10 RT Radiation Set Module (Current)
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### C.36.10 RT Radiation Set Module

The RT Radiation Set Module describes treatment fractions that contain a set of beams or brachytherapy setups used within a treatment session to help achieve the dosimetric requirements of a given Treatment Phase. The Module references a set of RT Radiation instances that describe the geometric and physical parameters that define the delivery of dose for a single fraction. In addition, the overall number of treatment fractions is defined, as well as possibly the fractionation scheme according to which, fractions will be delivered.

A Treatment Phase is achieved by delivering one or more RT Radiation Sets. The chronological relationships between RT Radiation Sets (the actual start of each set, the order or timing among sets, etc.) are recorded in Attributes outside the RT Radiation Set Module.

Table C.36.10-1. RT Radiation Set Module Attributes

Attribute Name | Tag | Type | Attribute Description
--- | --- | --- | ---
Include Table 10.9.1-1 “Enhanced Content Identification Macro Attributes”.
Intended Number of Fractions | (300A,0636) | 1C | Number of Fractions for which this RT Radiation Set is intended to be repeated. Required if Referenced RT Physician Intent Sequence (300A,063B) is empty. May be present otherwise. See Section C.36.10.1.4.
Include Table C.36.2.1.1-1 “Radiation Fraction Pattern Macro Attributes”. | See Section C.36.10.1.4.
Referenced RT Physician Intent Sequence | (300A,063B) | 2 | RT Physician Intent Instance this Radiation Set is based upon. Zero or more Items shall be included in this Sequence.
>Include Table 10-11 “SOP Instance Reference Macro Attributes”.
>Referenced RT Prescription Sequence | (300A,068A) | 1 | Sequence of RT Prescription Prescription Indices. One or more Items shall be included in this Sequence.
>>Referenced RT Prescription Index | (3010,0041) | 1 | Value of RT Prescription Index (3010,003C) in the RT Prescription Sequence (3010,006B) specifying the prescription to which this RT Radiation Set is related.
RT Radiation Set Intent | (300A,0637) | 1 | A general indication of the type of information contained within this RT Radiation Set. See Section C.36.10.1.1.
Treatment Position Group Sequence | (300A,060A) | 2 | Treatment Position Groups defined for the included Radiation Instances. Zero or more Items shall be included in this Sequence. See Section C.36.10.1.3.
>Treatment Position Group UID | (300A,0609) | 1 | Unique identifier of the Treatment Position Group.
>Treatment Position Group Label | (300A,0608) | 1 | User-defined label of the Treatment Position Group.
>Referenced RT Radiation Sequence | (300A,0630) | 1 | RT Radiation Instances that belong to the Treatment Position Group. Each referenced Radiation Instance shall appear once and only once in the Treatment Position Group Sequence (300A,060A). One or more Items shall be included in this Sequence.
>>Include Table 10-11 “SOP Instance Reference Macro Attributes”.
RT Radiation Sequence | (300A,0616) | 1 | RT Radiation instances which are referenced by this RT Radiation Set. One or more Items shall be included in this Sequence. See Section C.36.10.1.2.
>Include Table 10-11 “SOP Instance Reference Macro Attributes”.

#### C.36.10.1 RT Radiation Set Attribute Descriptions

##### C.36.10.1.1 RT Radiation Set Intent

Defined Terms for RT Radiation Set Intent (300A,0637)

TREATMENT

  The RT Radiation Set is for the purpose of treatment delivery. This does not constitute an approval for treatment. All parameters necessary to guide the delivery of RT Radiations are included.

PLAN_QA

  The RT Radiation Set is for validating the patient-specific dose. For example, by delivering the RT Radiations to a phantom and comparing the calculated dose to the phantom with actual measurements made in the phantom.

MACHINE_QA

  The RT Radiation Set is for system quality assurance and calibration (geometric, dosimetric or both) procedures of the delivery machine and is not patient-specific.

RESEARCH

  The RT Radiation Set is for performing research and is not delivered to a patient.

SERVICE

  The RT Radiation Set is for diagnostics and assessment for machine repair or to perform measurements for a maintenance or calibration operation by a service technician.

##### C.36.10.1.2 RT Radiation Sequence

All SOP Instances referenced in this Sequence shall:

- share the same Frame of Reference (defined by the Frame of Reference UID (0020,0052) in the Frame Of Reference Module), and

- be defined for the same treatment device (specified by the Treatment Device Identification Macro within the RT Delivery Device Common Module).

The SOP Classes referenced in this Sequence shall contain the following Modules:

- Section C.36.3 Enhanced RT Series Module.

- Section C.36.4 Radiotherapy Common Instance Module.

- Section C.36.12 RT Delivery Device Common Module.

- Section C.36.13 RT Radiation Common Module.

##### C.36.10.1.3 Treatment Position Groups

Radiation Instances that share a fixed spatial relation and thus can share the result of a position verification can be assigned to the same Treatment Position Group because the relationship of positions in one Instance to those in other Instances in the Treatment Position Group can be known with sufficient certainty to allow deterministic movement.

Whether it is reasonable to put Instances together in Treatment Position Group can depend on several factors and may involve a degree of judgment.

For example,

1. In a Radiation Set treating a single target with two beams at the same spatial location, both Radiation Instances belong to the same Treatment Position Group.

2. In a Radiation Set treating two targets in different anatomical regions (e.g., lung and pelvis), typically the Radiation Instances belong to different Treatment Position Groups, because a separate setup verification is required to establish the treatment position for each Radiation.

3. In a Radiation Set treating two targets whose spatial relationship is fixed such that a single setup verification is sufficient, the Radiation Instances may belong to the same Treatment Position Group, but the planner may choose to assign them to different Treatment Position Groups.

##### C.36.10.1.4 Intended Number of Fractions and Radiation Fraction Pattern Macro

The values of Intended Number of Fractions (300A,0636) and the attributes in Radiation Fraction Pattern Macro provide information about the planned treatment at the time the RT Radiation Set Instance was created.

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DICOM PS3.3 2020a - Information Object Definitions