Knowledge Hub · Saxsons Moving Laser Positioning
The treatment planning system exports the virtual iso-centre in DICOM RT; the Saxsons moving laser system reads the DICOM coordinates and drives the lasers directly to the planned position. Five times tighter than the AAPM TG-142 stereotactic-class threshold. One-axis, three-axis or five-axis configurations available. Closed-loop linear encoders hold ±0.2 mm reproducibility across the rail life. This page unpacks why.
Why this matters
±0.2 mm positioning accuracy
AAPM TG-142 sets the patient-positioning-laser tolerance at ≤ 2 mm for routine treatments and ≤ 1 mm for stereotactic-class work. The Saxsons movable system delivers ±0.2 mm positioning accuracy — a factor of five tighter than the stereotactic threshold. Same patient marked the same way twice ends up in the same place within ±0.2 mm. The reproducibility that virtual iso-centre tattooing absolutely requires, and that SBRT / SRS planning workflows depend on.
Based on: AAPM TG-142 — Quality Assurance of Medical Accelerators.
Read source ↗DICOM 3.0/RT TPS integration
The treatment planning system exports the virtual iso-centre as part of the DICOM RT plan. The moving laser system reads the DICOM coordinates directly and drives the lasers to the planned position. The radiation therapist does not enter coordinates by hand; the transcription-error class of failure is eliminated by removing the transcription. Every TPS that exports DICOM 3.0/RT (every modern TPS) drives this system without a vendor-specific bridge.
Based on: DICOM Standard PS3 — Radiation Therapy Objects; AAPM TG-101 SBRT patient setup guidance.
Read source ↗One-axis · three-axis · five-axis
A small department running routine 3D-CRT can deploy the one-axis version for basic patient marking. A standard radiotherapy department running IMRT and VMAT deploys the three-axis version for the full coordinate range. A stereotactic / SBRT-capable centre running complex multi-iso-centre treatments deploys the five-axis version for non-orthogonal coordinate systems. The same Saxsons engineering scales across the three configurations — buy what the workload needs today, upgrade when the workload grows.
Based on: Saxsons product configuration framework.
Read source ↗Closed-loop linear encoders
Exactitude linear guide rails carry the laser carriages along each axis. Linear-coding closed-loop feedback measures the actual carriage position continuously and corrects the drive against the target position. The ±0.2 mm reproducibility comes from this loop, not from open-loop stepper-motor counting that drifts over time. Position drift over the rail life is bounded by the encoder precision, not by mechanical wear.
Based on: Manufacturer drive specification; industrial closed-loop motion control practice.
Read source ↗Three control modes
Different operators want different control surfaces. The treatment-planning physicist prefers the computer workstation with full coordinate entry and DICOM plan import. The radiation therapist in routine use prefers the manual control box pendant at the patient couch. The on-call physicist debugging an alignment issue prefers WiFi control from a tablet at the linac iso-centre. The same Saxsons system supports all three modes from one control architecture.
Based on: Manufacturer control-interface design.
Read source ↗Paired offering with the fixed system
A complete radiotherapy department buys the movable laser system for the CT-simulator room and the fixed system for the treatment vault. Same Saxsons engineering team, same installation, same service contract. The commissioning record on the two systems references a single iso-centre standard; the alignment chain from CT-sim through treatment vault stays coherent. One supplier across procurement and lifecycle.
Based on: Saxsons paired-product framing; consistent with the Saxsons own-brand lifecycle approach.
Read source ↗AAPM and DICOM documents that frame CT-simulator and treatment-vault patient-positioning workflows.
AAPM framework for daily / monthly / annual linac and laser-positioning QA.
AAPM framework for patient-positioning systems across CT-simulator and treatment-vault rooms.
DICOM PS3 standard for radiotherapy plan, image and treatment data exchange.
AAPM framework for SBRT patient setup, including iso-centre marking and tattoo workflows.
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