Siemens PRIMUS
Siemens Healthineers · Model PRIMUS
Flexible treatment options with a single delivery system Time-saving features that enhance staff productivity Reliable performance resulting in consistent patient care Affordable solutions for providing advanced treatments A clear upgrade path for rapid implementation of future technological developments.
Typical Failure Modes
Compiled for this model from its own documentation and established engineering knowledge for this equipment class - not from a verified service record. Confirm against the manufacturer's service manual.
RF / magnetron (or klystron) output instability
HighSymptoms: Beam-on faults, dose-rate low or unstable, RF/HV or arc interlocks.
Root cause: Magnetron/klystron or thyratron at end of life, HV supply, or waveguide arcing / SF6 pressure loss.
MLC leaf fault
HighSymptoms: Leaf stuck or out of position, delivery interlock, QA fluence errors.
Root cause: MLC leaf motor, leaf-guide wear, or a leaf position-readout fault.
Gantry / collimator / couch drive fault
MediumSymptoms: Rotation, field-size or couch position error, position interlock.
Root cause: Drive motor, encoder, or brake.
Onboard imaging fault (kV / MV / CBCT)
MediumSymptoms: kV source or flat-panel imaging degraded, poor image for setup, imaging-arm deploy errors.
Root cause: kV X-ray tube, amorphous-silicon panel, or the imaging-arm drive.
Dosimetry / ion-chamber drift
HighSymptoms: Output constancy checks trend out, symmetry/flatness off, chamber interlock.
Root cause: Monitor ion-chamber aging or a dose-servo fault.
Water / thermal management fault
MediumSymptoms: Over-temperature interlocks, dose-rate instability, coolant-flow alarm.
Root cause: Chiller pump, heat-exchanger fouling, or low coolant.
Serviceable Parts & Consumables
Serviceable items for this model, compiled from its documentation and engineering knowledge for this equipment class. Service class and relative cost are estimates, not manufacturer figures; no part numbers are given. Confirm intervals and pricing against the manufacturer.
Magnetron / klystron
OEM service; dosimetry re-commissioning required.
Class Periodic replacementRel. cost $$$$R&R Expert-level
Thyratron
Class Periodic replacementRel. cost $$$$R&R Expert-level
MLC leaf motor / drive assembly
Class Major service partRel. cost $$$$R&R Expert-level
kV X-ray tube / a-Si imaging panel
Class Major service partRel. cost $$$$R&R Expert-level
Monitor ion chamber
Class Major service partRel. cost $$$$R&R Expert-level
Chiller pump / heat exchanger
Class Major service partRel. cost $$$R&R Difficult
| Part | Service class | Relative cost | R&R difficulty |
|---|---|---|---|
| Magnetron / klystron OEM service; dosimetry re-commissioning required. | Periodic replacement | $$$$ | Expert-level |
| Thyratron | Periodic replacement | $$$$ | Expert-level |
| MLC leaf motor / drive assembly | Major service part | $$$$ | Expert-level |
| kV X-ray tube / a-Si imaging panel | Major service part | $$$$ | Expert-level |
| Monitor ion chamber | Major service part | $$$$ | Expert-level |
| Chiller pump / heat exchanger | Major service part | $$$ | Difficult |
Relative cost: $ lowest · $$$$ highest service-part cost for this equipment class. Not a price.
Troubleshooting Approach
A starting sequence for this model, compiled from its documentation and engineering knowledge for this equipment class. Follow the manufacturer's service documentation for the actual procedure.
Symptom: Beam-on / RF fault
- This is an OEM-service linac - the BMET role is triage and coordination.
- Record the exact fault codes from the console and the modulator / equipment-room logs.
- Check chiller status and coolant flow first - thermal faults mimic RF faults.
- Verify SF6 / waveguide pressure.
- Escalate a confirmed magnetron / thyratron / waveguide fault to Siemens / Varian service; keep the unit down until physics re-verifies output.
Symptom: MLC or field-size interlock
- Note the leaf / diaphragm and the exact interlock.
- Review the daily QA and delivery-log trend.
- Run the MLC calibration / diagnostic where the procedures allow.
- Escalate a confirmed leaf-drive or readout fault to Siemens / Varian service.
- Coordinate with physics before resuming clinical use.