Brachy Task Sequence Attribute
| Tag | (0074,1401) |
|---|---|
| Type | Required (1) |
| Keyword | BrachyTaskSequence |
| Value Multiplicity | 1 |
| Value Representation | Sequence (SQ) |
Specification of Brachy Application Setups to be delivered.
One or more Items shall be included in this Sequence.
See Section C.8.8.30.1.
Section C.8.8.30.1
C.8.8.30.1 Brachy Task Sequence
The Brachy Task Sequence (0074,1401) contains instructions for the delivery of a single treatment session. A treatment session is the time that the patient is connected to the treatment delivery system. During a treatment session, one fraction of the referenced plan is delivered. If the value of Brachy Treatment Type (300A,0202) in the reference RT Plan is HDR, the entire fraction is delivered at one time. If the value is PDR, the fraction is divided into a number of pulses which are delivered periodically during the treatment session.
The Application Setup groups together the channels to be delivered. The task Sequence can also contain the delivery order of the channels. The Omitted Application Setup Sequence (0074,140E) contains the channels to skip in the case of continuation of an interrupted treatment.
Figure C.8.8.30-2. Relation of the Fraction, Pulse and Channels within the RT Brachy Task Sequence
The following scenarios demonstrate the usage of the RT Brachy Application Setup Delivery Instruction Module for the Treatment Management System (TMS) to instruct the Treatment Delivery System (TDS) to initiate brachytherapy treatment and continue an interrupted delivery.
C.8.8.30.1.1 Usage Scenario 1: HDR Treatment, Interruption Skipping Remainder of the Interrupted Delivery
Brachytherapy plan overview:
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Plan1, HDR, 2 fractions;
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Channel1, two dwell positions, 10 sec + 10 sec
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Channel2, two dwell positions, 10 sec + 10 sec
Treatment session 1:
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Treatment Management System (TMS):
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Requests the delivery of the first fraction of the plan:
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RT Brachy Application Setup Delivery Instruction:
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Referenced RT Plan Sequence (300C,0002) = UID of "Plan1"
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Referenced Fraction Group Number (300C,0022) = 1
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Current Fraction Number (3008,0022) = 1
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Brachy Task Sequence (0074,1401):
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Treatment Delivery Type (300A,00CE) = TREATMENT
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Referenced Brachy Application Setup Number (300C,000C) = 1
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Treatment Delivery System (TDS):
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Delivers the first fraction and returns a RT Brachy Treatment Record that describes interruption at channel 2 after 9 seconds of the second dwell position is being delivered.
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Treatment session 2:
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It has been decided to proceed to fraction 2 without delivering the remainder of fraction 1. This is not a continuation case.
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Treatment Management System (TMS):
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Requests the delivery of the second fraction of the plan:
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RT Brachy Application Setup Delivery Instruction:
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Referenced RT Plan Sequence (300C,0002) = UID of "Plan1"
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Referenced Fraction Group Number (300C,0022) = 1
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Current Fraction Number (3008,0022) = 2
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Brachy Task Sequence (0074,1401):
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Treatment Delivery Type (300A,00CE) = TREATMENT
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Referenced Brachy Application Setup Number (300C,000C) = 1
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-
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Treatment Delivery System (TDS) :
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Delivers the second fraction and returns a RT Brachy Treatment Record that describes a complete delivery of that fraction.
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C.8.8.30.1.2 Usage Scenario 2: PDR Treatment, Interruption and Continuation
Brachytherapy plan overview:
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Plan2, PDR, 10 pulses;
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Channel1, two dwell positions, 50 sec + 50 sec
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Channel2, two dwell positions, 50 sec + 50 sec
Treatment Session 1
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Treatment Management System (TMS):
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Requests the delivery of the first fraction of the plan:
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RT Brachy Application Setup Delivery Instructions:
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Referenced RT Plan Sequence (300C,0002) = UID of "Plan2"
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Referenced Fraction Group Number (300C,0022) = 1
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Current Fraction Number (3008,0022) = 1
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Brachy Task Sequence (0074,1401):
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Treatment Delivery Type (300A,00CE) = TREATMENT
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Referenced Brachy Application Setup Number (300C,000C) = 1
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Treatment Delivery System (TDS) :
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Delivers the first fraction and returns a RT Brachy Treatment Record that describes interruption at pulse 5 of the first fraction at channel 2, after 25 seconds of the first dwell position was delivered. Total Reference Air Kerma Delivered was 100.
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Treatment Session 2
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It has been decided to proceed to fraction 2 to deliver the remainder of the interrupted plan as instructed by the following task transmitted inside the delivery instruction:
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The remainder is defined as to skip 25 sec of the first dwell position of channel 2 and continue with the second dwell position.
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Treatment Management System (TMS):
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Requests the continuation of the delivery of the first fraction of the plan:
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Referenced RT Plan Sequence (300C,0002) = UID of "Plan2"
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Referenced Fraction Group Number (300C,0022) = 1
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Current Fraction Number (3008,0022) = 1
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Continuation Pulse Number (0074,1404) = 5
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Brachy Task Sequence (0074,1401):
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Treatment Delivery Type (300A,00CE) = CONTINUATION
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Continuation Start Total Reference Air Kerma (0074,1402) = 100
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Continuation End Total Reference Air Kerma (0074,1403) = 1000
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Referenced Brachy Application Setup Number (300C,000C) = 1
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Channel Delivery Order Sequence (0074,1405):
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Referenced Channel Number (0074,1406) = 2
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Channel Delivery Order Index (0074,140C) = 1
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Channel Delivery Continuation Sequence (0074,140D):
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Referenced Channel Number (0074,1406) =2
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Start Cumulative Time Weight (0074,1407) = 50
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End Cumulative Time Weight (0074,1408) = 100
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Omitted Application Setup Sequence (0074,140E):
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Referenced Brachy Application Setup Number (300C,000C) = 1
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Omitted Channel Sequence (0074,1409):
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Referenced Channel Number (0074,1406) = 1
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Reason for Channel Omission (0074,140A) = ALREADY_TREATED
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Treatment Delivery System (TDS):
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Delivers the first fraction and returns RT Brachy Treatment Record that describes that the treatment first fraction was continued and the reminder was delivered fully (including the rest of the pulses from 6-10).
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