C.8.8.29 RT Beams Delivery Instruction Module

The RT Beams Delivery Instruction Module contains additional information required by a Treatment Delivery System (TDS) when specifying delivery of an external beam radiotherapy treatment. This information is supplied by a Treatment Management System (TMS) when it creates an RT Beams Delivery Instruction SOP Instance, a composite SOP Instance in turn referenced by a Unified Procedure Step (UPS) in the Unified Procedure Step model.

The RT Beams Delivery Instruction Module consists of a sequence of one or more beam tasks, where each beam task may also specify one or more Delivery Verification images to be acquired prior to, during, or after the treatment delivery.

Table C.8.8.29-1 RT BEAMS DELIVERY INSTRUCTION MODULE ATTRIBUTES

Attribute Name Tag Type Description
Referenced RT Plan Sequence (300C,0002) 1 Reference to a single RT Plan or RT Ion Plan SOP Instance (whose UID is also supplied in the Input Information Sequence – see PS3.4) containing all the Beams and the Fraction Group referenced in this SOP Instance. Only a single item shall be included in this sequence.
>Include 'SOP Instance Reference Macro' Table 10-11
Beam Task Sequence (0074,1020) 1 Specification of beams to be delivered and/or verified. One or more Items shall be included in this sequence.
>Beam Task Type (0074,1022) 1 Indication whether beam is to be verified, treated (delivered), or both. Enumerated Values: VERIFY = Beam verification only TREAT = Beam treatment only VERIFY_AND_TREAT = Beam verification and treatment
>Treatment Delivery Type (300A,00CE) 1 Delivery Type of treatment. Enumerated Values: TREATMENT = normal patient treatment CONTINUATION = continuation of interrupted treatment
>Primary Dosimeter Unit (300A,00B3) 1C Measurement unit of machine dosimeter. Enumerated Values: MU = Monitor Unit MINUTE = minute NP = Number of Particles This value shall be the same as in the referenced RT Plan. It applies only to the Continuation Start Meterset (0074,0120) and Continuation End Meterset (0074,0121). Required if Delivery Type (300A,00CE) is CONTINUATION.
>Continuation Start Meterset (0074,0120) 1C Meterset within Beam referenced by Referenced Beam Number (300C,0006) at which treatment delivery starts, in units specified by Primary Dosimeter Unit (300A,00B3). Required if Delivery Type (300A,00CE) is CONTINUATION.
>Continuation End Meterset (0074,0121) 1C Meterset within Beam referenced by Referenced Beam Number (300C,0006) at which treatment delivery ends, in units specified by Primary Dosimeter Unit (300A,00B3). Required if Delivery Type (300A,00CE) is CONTINUATION.
>Current Fraction Number (3008,0022) 1 The index of the fraction that is to be delivered or completed in this session. See C.8.8.29.1.
>Referenced Fraction Group Number (300C,0022) 1C Indicates which fraction group of the referenced plan is to be treated in the treatment session. Only one Fraction Group shall be specified per Delivery Instruction SOP Instance. Required if the referenced plan has more than one Fraction Group Sequence (300A,0070) item.
>Referenced Beam Number (300C,0006) 1 Uniquely identifies the Beam which is specified by Beam Number (300A,00C0) within Beam Sequence (300A,00B0) in RT Beams Module of referenced RT Plan or RT Ion Plan.
>Beam Order Index (0074,1024) 3 Identifies required ordering of beam delivery, monotonically increasing by 1, starting from 1.
>Table Top Vertical Adjusted Position (0074,0126) 2 Adjusted Table Top Vertical position in the IEC TABLE TOP coordinate system in mm for patient setup. See C.8.8.29.2.
>Table Top Longitudinal Adjusted Position (0074,0127) 2 Adjusted Table Top Longitudinal position in the IEC TABLE TOP coordinate system in mm for patient setup. See C.8.8.29.2.
>Table Top Lateral Adjusted Position (0074,0128) 2 Adjusted Table Top Lateral position in the IEC TABLE TOP coordinate system in mm for patient setup. See C.8.8.29.2.
>Patient Support Adjusted Angle (0074,102A) 2 Adjusted Patient Support angle for patient setup, i.e. orientation of the IEC PATIENT SUPPORT coordinate system with respect to the IEC FIXED REFERENCE coordinate system in degrees. See C.8.8.29.2.
>Table Top Eccentric Adjusted Angle (0074,102B) 2 Adjusted Table Top (non-isocentric) angle for patient setup, i.e. orientation of the IEC TABLE TOP ECCENTRIC coordinate system with respect to the IEC PATIENT SUPPORT system in degrees. See C.8.8.29.2.
>Table Top Pitch Adjusted Angle (0074,102C) 2 Adjusted Table Top Pitch Angle for patient setup, i.e. the rotation of the IEC TABLE TOP coordinate system about the X-axis of the IEC TABLE TOP coordinate system in degrees. See C.8.8.29.2.
>Table Top Roll Adjusted Angle (0074,102D) 2 Adjusted Table Top Roll Angle for patient setup, i.e. the rotation of the IEC TABLE TOP coordinate system about the Y-axis of the IEC TABLE TOP coordinate system in degrees. See C.8.8.29.2.
>Table Top Vertical Setup Displacement (300A,01D2) 2 Vertical Displacement in the IEC TABLE TOP coordinate system in mm relative to initial Setup Position, i.e. vertical offset between patient positioning performed using setup and treatment position.
>Table Top Longitudinal Setup Displacement (300A,01D4) 2 Longitudinal Displacement in the IEC TABLE TOP coordinate system in mm relative to initial Setup Position, i.e. longitudinal offset between patient positioning performed using setup and treatment position.
>Table Top Lateral Setup Displacement (300A,01D6) 2 Lateral Displacement in the IEC TABLE TOP coordinate system in mm relative to initial Setup Position, i.e. lateral offset between patient positioning performed using setup and treatment position.
>Delivery Verification Image Sequence (0074,1030) 2C Beam verification images to be acquired for current beam. Required if Beam Task Type (0074,1022) is VERIFY or VERIFY_AND_TREAT. Zero or one Item shall be included in this sequence if Beam Task Type (0074,1022) is VERIFY. Zero or more Items shall be included in this sequence if Beam Task Type (0074,1022) is VERIFY_AND_TREAT.
>>Verification Image Timing (0074,1032) 1 Indicates the temporal relationship of the verification image with respect to the current treatment beam delivery. Value shall be DURING_BEAM for Beams with a Beam Task Type (0074,1022) of VERIFY. Enumerated Values: BEFORE_BEAM DURING_BEAM AFTER_BEAM
>>Start Cumulative Meterset Weight (300C,0008) 1C Cumulative Meterset Weight within current Beam at which image acquisition will start. Required if Verification Image Timing (0074,1032) is DURING_BEAM.
>>Meterset Exposure (3002,0032) 2C Treatment machine Meterset duration over which image is to be acquired, specified in Monitor units (MU) or minutes as defined by Primary Dosimeter Unit (300A,00B3) specified in the Referenced RT Plan Sequence (300C,0002). Required if Verification Image Timing (0074,1032) is BEFORE_BEAM or AFTER_BEAM. See C.8.8.29.3.
>>End Cumulative Meterset Weight (300C,0009) 2C Cumulative Meterset Weight within current Beam at which image acquisition will end. Required if Verification Image Timing (0074,1032) is DURING_BEAM.
>>Double Exposure Flag (0074,1034) 1 Indicates whether the current verification image is a single or double exposure. Enumerated Values: SINGLE = single exposure DOUBLE = double exposure
>>Double Exposure Ordering (0074,1036) 1C Indicates the ordering of the open (double exposure) field with respect to the primary (collimated) field in a double exposure. Defined terms: OPEN_FIRST = Open field first OPEN_SECOND = Open field second Required if Double Exposure Flag (0074,1034) is DOUBLE.
>>Double Exposure Meterset (0074,1038) 2C If this field is present, an additional exposure with the indicated Meterset is requested. Required if Double Exposure Flag (0074,1034) is DOUBLE.
>>Double Exposure Field Delta (0074,103A) 2C Offsets of field-defining edges in mm for the double exposure in the IEC BEAM LIMITING DEVICE coordinate system in the IEC order X1, X2, Y1, Y2. Negative values for X1 and Y1 indicate an enlarged field, negative values for X2 and Y2 indicate a reduced field. Required if Double Exposure Flag (0074,1034) is DOUBLE. See C.8.8.29.4.
>>X-Ray Image Receptor Translation (3002,000D) 2 Position in (x,y,z) coordinates in mm of origin of the IEC X-RAY IMAGE RECEPTOR System in the IEC GANTRY coordinate system.
>>Related Reference RT Image Sequence (0074,1040) 3 Uniquely identifies Reference Images to which planned verification image is related. All items in this sequence shall be RT Image SOP Instances. One or more items are permitted in this sequence.
>>>Include 'SOP Instance Reference Macro' Table 10-11

C.8.8.29.1 Current Fraction Number

For beams with a Treatment Delivery Type (300A,00CE) of CONTINUATION, the Current Fraction Number (3008,0022) is that of the original fraction to be completed by the current beam.

C.8.8.29.2 Adjusted Table Positions and Angles

Adjusted Table positions and angles serve as a facility to communicate a shift (often systematic) that has been detected from previous treatments. They define a new initial patient position, which is near and aligned to the actual patient position during beam delivery. These attributes do not affect the original relationship between the beams and the planning image patient anatomy.

C.8.8.29.3 Meterset Exposure

Meterset Exposure (3002,0032) can be interpreted as the ‘maximum’ meterset duration in cases where an automatic exposure is taken.

C.8.8.29.4 Double Exposure Field Delta

The following diagram illustrates the case where the second X aperture in a double exposure is larger than the initial aperture. In this case ∆X1 is negative and ∆X2 is positive. If a field edge is defined by a multileaf collimator, then the field delta is to be applied to the most open leaf, such that all leaves can be moved to that position.

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