YY/T 1711-2020 English PDF (YYT1711-2020)
YY/T 1711-2020 English PDF (YYT1711-2020)
YY/T 1711-2020: Gating interface used in radiation therapy
PHARMACEUTICAL INDUSTRY STANDARD
OF THE PEOPLE'S REPUBLIC OF CHINA
Gating interface used in radiation therapy
ISSUED ON: JUNE 30, 2020
IMPLEMENTED ON: JUNE 1, 2022
Issued by: National Medical Products Administration
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Terms and definitions ... 4
4 Requirements and test methods ... 6
4.1 Electrical interface ... 6
4.2 Conditions for the beam termination function to work properly ... 6 4.3 Delay time of beam hold switching action ... 6
4.4 Gating time ... 7
4.5 Error handling and recovery ... 7
4.6 Basic operation and basic performance ... 7
References ... 10
Gating interface used in radiation therapy
This standard specifies the technical requirements and test methods for gating interfaces used in radiation therapy.
This standard applies to gating interfaces for radiation therapy. Each manufacturer may have other safety design and functional design solutions.
2 Normative references
The following documents are essential for the application of this document. For the dated referenced documents, only the versions with the indicated dates are applicable to this document; for the undated referenced documents, only the latest versions (including all the amendments) are applicable to this document.
GB 9706.5-2008 Medical electrical equipment - Part 2-1: Particular requirements for the safety of electron accelerators in the range 1 MeV to 50 MeV
GB 9706.17-2009 Medical electrical equipment - Part 2: Particular requirements for the safety of gamma beam therapy equipment
3 Terms and definitions
The terms and definitions defined in GB 9706.5-2008, GB 9706.17-2009, and the following apply to this document.
3.1 beam hold
The state in which the system is ready to quickly resume beaming on but has not been beaming on.
NOTE 1: Beam hold and interrupt irradiation (the equipment changes to the beam-off state) are not the same.
NOTE 2: Beam hold is a sub-state of the irradiation state, and its purpose is to quickly transform into the expected therapeutic irradiation state.
NOTE 3: It is usually used in gating, IMRT, etc.
3.2 beam off
The radiation source is completely shielded and in a safe protective position. [GB 9706.17-2009, Definition of 2.101]
3.3 beam termination/terminate irradiation
The signal that is transmitted from the PPMS (Patient Position Monitoring System) to the TDD (Treatment Delivery Device) to prohibit the start of irradiation or to immediately terminate irradiation.
NOTE: TDD in this standard mainly includes medical electron accelerators, light ion therapy systems, gamma ray beam stereotactic radiotherapy systems, cobalt 60 remote machines, and other equipment; PPMS mainly includes optical surface, X-ray transmission, abdominal pressure, magnetic field signals, ultrasound imaging, magnetic resonance imaging, and other position monitoring systems. 3.4 gating interface
The purpose of the gating interface is to enable TDD and PPMS to have the following capabilities:
a) Perform beam hold or "beam termination/terminate of irradiation" according to the movement of the target area in the patient's body or the position of the patient without operator intervention.
b) Switch off the beam in case of error or patient status exceeding deviation limits. NOTE: PPMS can change the beam generation state of TDD through two control methods. Both require hard wiring between PPMS and TDD. The first type is beam gating connection, which is beam hold. It allows the PPMS to temporarily maintain the beam without triggering the beam off. The second type is gating interlocking. It allows the PPMS to require beam termination (i.e., beam off in GB 9706.5-2008) or prohibit beam-on when an error is detected.
A setting that prevents a device from starting or continuing operation under unspecified conditions.
NOTE: A signal that causes the gating device to terminate the beam. Note that when an interlock occurs, the operator is required to take action to confirm the interlock and then resume the treatment after the interlock is cleared.
3.6 interrupt irradiation
The PPMS sends the signal for interrupt irradiation to TDD, and the restart of irradiation requires user intervention.
4.4 Gating time
The TDD manufacturer should provide the minimum value of the beam hold time and other restrictions, and the PPMS manufacturer should provide the corresponding configuration.
4.5 Error handling and recovery
4.5.1 TDD error log
If the gating interlock causes abnormal beam termination, TDD shall record it in the event log.
4.5.2 PPMS fail-safe protection
When the PPMS requests abnormal beam termination or the system is in a fault state, the PPMS shall be required to:
a) Trigger external gating interlock. Whenever the gating interlock is triggered, TDD shall implement beam off.
b) Trigger an external beam hold signal to complete beam gating (if applicable). c) Provide status checking of the communication mechanism (if applicable). TDD will implement beam off (or interrupt irradiation) after receiving the PPMS error states.
PPMS manufacturers shall design logging and inspection capabilities in their products to effectively analyze potential gating interface errors or failures (if applicable). 4.6 Basic operation and basic performance
The interface design between TDD and PPMS can include but is not limited to the following functions:
a) The gating interface shall not interfere with the operator's initialization of treatment or imaging procedures.
b) With the help of a gating interface, PPMS allows beam hold and "beam termination/terminate irradiation" without additional operator intervention. c) Gating interfaces shall not prohibit the use of therapeutic irradiation and imaging equipment without the functionality of the PPMS monitoring
d) If provided, the two interfaces "beam hold" and "beam termination/terminate irradiation" shall be independent of each other.
e) If provided, before irradiation, TDD shall check to ensure that the functions of beam hold and "beam termination/terminate irradiation" are correct.
f) Before irradiation, the PPMS shall check to ensure that it can operate the signal of the beam hold. This inspection shall be performed before the PPMS releases the "beam termination/terminate irradiation" interlock.
g) Before irradiation begins, the PPMS shall perform an end-to-end beam hold and "beam termination/terminate irradiation" signal check by actually
activating the (open circuit or "fail-safe") switch and receiving a confirmation signal from the TDD, and then it can release the "beam termination/terminate irradiation" interlock.
h) If the PPMS cannot work properly, the "beam termination/terminate
irradiation" interlock for fail-safe shall inhibit beam start by default. Any apparent PPMS error shall inhibit the activation of the treatment beam. i) If the PPMS can receive and respond to beam irradiation information (beam hold state or MU of the beam-on), it shall be expected that, after the beam hold request is sent, the PPMS can trigger the beam termination interlock when it notices that the TDD has not switched to the beam hold state, or MU is still increasing.
j) Both PPMS and TDD shall have continuous interface checks. If TDD detects that the PPMS does not respond to messages within the expected time period, TDD should terminate beam-on within a specified time period. If the PPMS detects a situation that affects the operation of the gating interface, the PPMS shall trigger the "beam termination/terminate irradiation" interlock within the specified time period.
k) If the action of the gating interface exceeds the stated performance limits (for example, the "maximum beam hold period" stated in the accompanying
documents provided by the TDD manufacturer is exceeded), the TDD shall be allowed to terminate the beam.
NOTE: The beam termination mentioned here can be a complete beam termination (resulting in an incomplete beam-on) or switching to a paused irradiation state that requires user intervention to resume beam-on.
l) If the PPMS has triggered the "beam termination" interlock and detects that the beam is still in progress (that is, the beam termination signal does not work), the PPMS shall give an alarm signal of this failure mode to alert the operator.