• Author / Uploaded
• Mohammad Mahfujur Rahman

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ACC

COLL

ACC disables collimator and gantry motions and prevents treatment. It occurs, when accessory selected does not match the mounted accessory or accessory is improperly positioned Facility air pressure is under 30 psig. Other than AIR, TARG and CARR interlocks can be caused by inadequate air pressure? Bend magnet power supply voltage is +/- 5% of set value or bend magnet current is +/1% too high or low for the energy mode. BMAG is a latching fault. Carrousel is not in position for selected mode or communication failure between the console computer and the carrousel controller. External customer-defined dosimetry interlock has tripped. During the calibration cycle, the controller activated these interlocks, but the console did not detect one or more of them Check cycle not completed before time-out Calibration failed during calibration and check Calibration cycle took too long and did not finish before time-out External customer-defined minor interlock is activated. Console controller did not receive the required configuration data from the console computer Incorrect portion of collimator jaws.

CTRL

An abnormal operating condition was detected by the console control computer

DOOR DOS1

Treatment room door is open The number of accumulated monitor units in the primary dosimetry channel equals the value set for MU1. DOS1 is displayed, when normal treatment is complete For all clinical mode or electron treatments, the number of accumulated MUs in the secondary dosimetry channel is 10% or 25 MU greater than the preset dose. For TBIx, TBe-, and HDTSe- treatments, the number of accumulated MUs in the secondary dosimetry channel is 10% greater than the preset dose.

AIR BMAG

CARR CDOS CKFA CKTO CLFA CLTO CMNR CNF

DOS2

DS12

DSFA DPSN

ENSW

Readings for MU1 and MU2 are not within 5% of one another. DS12 is very important for dynamic treatments because a specific relationship between the dose delivered and one or more axis positions is closely controlled Console computer detected that the actual dose is greater than the set dose The beam has been terminated because a physical element is not in the correct position or due to out-of-tolerance respiratory gating Causes of the DPSN interlock are: element: -during dynamic MLC mode, at least one leaf is outside the leaf position tolerance -during ARC dynamic mode, the gantry position is out of tolerance gating: -there is an external beam hold of more than 30 seconds -the beam is held off by clinical conditions for more than 15 seconds The accelerator's energy switch is not in the correct position for the selected mode. If the ENSW and AIR interlocks appear at the same time, there may be a problem with the pneumatic air system that moves the energy switch

EXQ1

EXQT EXT

Radial beam symmetry is out of tolerance or the instantaneous dose rate exceeds 800 MU/min in one pulse Transverse beam symmetry is out of tolerance or the instantaneous dose rate exceeds 800 MU/min in one pulse All interlocks related to EXQ1 and EXQ2 must be asserted LINAC and RV setups do not agree or the RV system has detected a malfunction

FLOW

Insufficient water flow opened a flow switch in the stand or gantry unit

FOIL

Carrousel locking pin is not in the home position. FOIL interlock is caused by any faulty operation sensed by the carrousel controller Waveguide dielectric gas pressure is below 30 psig

EXQ2

GAS GFIL

HVCB HVOC

HWFA ION1 ION2 IPSN KEY KFIL KSOL LVPS MLC MOD MODE MOTN ORNT

PNDT PUMP RVBP STPR

The filament and bis voltage are below proper operating level for the accelerator gun. In digital gun drivers, GFIL interlock appear, when any faulty condition detected by the gun controller Controlled by the modulator's primary power distribution and main thyratron chassis. Look at the breaker handle to detect a circuit breaker trip. Controlled by card rack circuits and may be asserted due to overcurrent such as: -peak charging current of the high-voltage power supply exceeding 7 amps -average charging current of the high-voltage power supply exceeding 1.5 amps Control processor detected a minor hardware failure Radial ion chamber power supply voltage is less than -400V DCTransverse ion chamber power supply voltage is less than -400V DCOne or more position parameters downloaded from the treatment delivery software do not agree with the actual position parameters The disable/enable key-switch on the dedicated keyboard is in the disable position. The klystron filament current is at or below half nominal value. KFIL is disabled after 5 seconds of the power key is turned on Klystron solenoid power is low. Low voltage power supply (+12, +/- 15, or +5 V) failed The multileaf collimator is preventing accelerator operation. Negative voltage buildup (exceeding 9.5 V) on the modulator pulse-forming network at the input to the sensing circuit The selected energy mode does not match the check code returned from the console controller. The unplanned motions were probably caused by the patient moving on the treatment couch Orientation selected at the console for a dynamic wedge treatment does not match the orientation selected in the treatment room or the dynamic wedge orientation has not been verified in the treatment room. Hand pendant is not in the pendant cradle on the treatment couch or treatment couch longitudinal and/or lateral brakes are not engaged at the treatment couch side panel The water tank level is low or the pump was shut off manually or by a fault condition. FLOW is the most common interlock when a water pump failure occurs. One or more beam parameters downloaded by the treatment delivery software differ from the actual beam setting at the accelerator The beam stopper is not fully extended or retracted

STPS TARG

TDLY

TDRV

TIME

Fault detected in steering or motor power circuits in the stand Target is not in the correct position for the selected mode. Three target positions are: -extended into the electron beam for high-energy x-rays -partially into the electron beam for low-energy x-rays -out of the electron beam in the electron mode A time delay of 12 minutes for component warm-up allows the klystron, modulator, and thyratron filaments to reach their operating temperature. Time delay starts, when the power key is turned from off to on. The length of the delay determines, how long the machine was off The RF-system shunt-tee power-attenuator turntable is not in the correct position for the selected mode and the power attenuator system setting disagrees with the energy set at the console The displayed beam-on time is greater than or equal to the value set for time

UDR1

Underdose rate is determined by too few MU per time or per servo period for UDR1, the radial dose rate is less than 80% of the set value. UDR2 Underdose rate is determined by too few MU per time or per servo period for UDR2, the transverse dose rate is less than 80% of the set value UDR1 and UDR2 interlocks are used for all fixed treatments with dose rates greater than or equal to 20 MU/min. UDR1 and UDR2 interlocks stop being disabled, after the first 10 seconds after beam-on. UDRS Underdose rate is determined by too few MU per time or per servo period for UDRS, the servoed dose rate was below that intended permits detection of a possible dosimetry error in all modes VAC1 There is a major leak somewhere in an area controlled by the power supply circuits that monitor pump current. If the current remains high or increases, the pump should stall and there could be excessive damage to the waveguide, circulator, klystron, or bend magnet. A pressure increase in the accelerator waveguide indicates that an increase in current above 2 mA thus causing the VAC1 interlock. VAC1 disconnects the primary power supply circuits. VAC2 May be an impurity, minor leak, or transient release of gas somewhere in the system. VAC2 is controlled by gantry VacIon circuits. When VAC2 appears, the increase in current might indicate an increase in the pressure on the klystron or accelerator guide VSWR Voltage standing wave ratio at the klystron directional coupler exceeds 1.5 to 1 XDP1 XDP2 XDR1

XDR2

XDRS

System delivered a radial dose per pulse greater than or equal to 150% of normal in HDTSe- mode, or greater than or equal to 200% of normal in non-HDTSe- modes System delivered a transverse dose per pulse greater than or equal to 150% of normal in HDTSe- mode, or greater than or equal to 200% of normal in non-HDTSe- modes System delivered a radial dose rate greater than or equal to 150% of the set dose rate in non-HDTSe- modes, or greater than or equal to 1000 MU/min in HDTSe- modes (calibrated at 1.6 meters) System delivered a transverse dose rate greater than or equal to 150% of the set dose rate in non-HDTSe- modes, or greater than or equal to 1000 MU/min in HDTSe- modes (calibrated at 1.6 meters) The actual servoed dose rate, over a given period of time, was above that intended