By Vvon Engineering Team | Published | Updated
Why external positioning lasers exist alongside the scanner's own, what fixed, manual and motorised systems each buy you, how alignment is established at installation, and the checks that catch drift before it reaches a patient.
Nuclear medicine RFQ checklist (TXT)
CT simulation may use external room lasers to transfer a planned reference or isocentre to the patient setup. Scanner-integrated lasers have model-specific locations and functions, so first establish which reference and movement the clinical workflow requires.
The distinction matters in nuclear medicine too, wherever a study has to be reproduced later or fed into a treatment plan.
Room-laser systems can provide an accessible reference outside the scan plane and, where supported, move to planned coordinates. Confirm the scanner's existing laser functions, couch offsets, indexing and treatment-planning interfaces before specifying another system.
External lasers define that point. A sagittal laser establishes the midline along the couch axis, and lateral lasers establish the height and the transverse position from both sides. Their intersection is the reference, sometimes called the virtual isocentre, and the couch offset between it and the scan plane is a number that has to be measured, recorded and protected.
External lasers may support reproducible positioning or an imaging-to-radiotherapy workflow where the clinical team requires them. They are not universally needed for routine nuclear medicine and do not independently establish SPECT/CT registration or eliminate differences between follow-up studies.
The choice is essentially about whether you need to move the reference point, and how often. Moving it by hand is fine at low volume and becomes the bottleneck at high volume.
| Type | What it gives you | Where it fits |
|---|---|---|
| Fixed laser set | A single reference point, sagittal and lateral lines, no adjustment during use | Diagnostic imaging rooms and nuclear medicine rooms needing consistent set-up rather than offset marking |
| Manually adjustable set, such as the Cemar Electro MAXX-600 Series | Lines that can be moved by hand against a scale to a required offset | Departments doing planning work at modest volume, and budget constrained simulator rooms |
| MAXX-700 | Motor-driven alignment adjustment and automatic alignment verification | Manufacturer specifies +/-10 mm horizontal/vertical adjustment; do not equate it with a long-travel CT simulation system |
| MAXX-1100 CT room system | Motorised CT-room positioning with DICOM-based interface | Manufacturer lists +/-300 mm travel; verify the complete scanner/planning integration and supplied configuration |
Confirm the exact configuration, mounting arrangement, control interface and available options for each MAXX series at quotation stage. The CT room system is the MAXX-1100 CT Room Laser Patient Positioning System, and its control interface is the MAXX-1100 CT Laser Desktop Application. These ranges are supplied in more than one build, and the difference between builds is what determines whether the system integrates with your scanner and your planning software.
Distinguish adjustment used to establish alignment from routine movement to treatment-planning coordinates. Choose the required travel, control and verification functions from the workflow. A fixed or manual unit is not interchangeable with a CT simulation system merely because it projects similar lines.
Lasers are the last item to be considered in a room design and the first to run into what is already there. Check the following against the room drawing before ordering, not on the day of installation.
Have qualified installation and medical-physics teams establish and document the relationship between imaging coordinates, couch motion, laser references and any planning interface. Agree phantom verification, tolerances, records and return-to-service checks. Use manufacturer procedures; a generic sequence of wall marks is not a complete commissioning method.
Step three catches the fault that causes most trouble later. A sagittal laser aligned to the room rather than to the couch travel can be perfect at one couch position and out by a few millimetres when the couch is driven in. Nobody notices until a patient is marked at an unusual couch position, and by then the error has been in the room for months.
AAPM Task Group 66 provides CT simulation QA guidance. Apply the relevant guidance, current requirements and manufacturer instructions through the institution's physics programme; tolerances need an appropriate basis and cannot be chosen solely by visual preference.
Define routine checks, periodic geometric verification and checks after relevant service or building changes through the approved QA programme. Include the reference, method, tolerance, action and responsible person. A service engineer may perform agreed checks, but clinical release still needs the specified evidence and responsibilities.
Measure and record the projected line width at commissioning as well as its position. Diodes dim and lines broaden with age, and a recorded starting value is the only way to tell a gradual degradation from a memory of how it used to look.
Plan checks for mounting stability, reference drift, line visibility, power and control faults. Use only authorised adjustment and maintenance methods; do not add a generic annual torque operation or unapproved electrical connection. Replacement time and service scope vary, so obtain the actual parts and support arrangements.
Send Vvon the scanner, planning workflow, room drawing and required laser movement to discuss Cemar MAXX options. Confirm compatibility, mounting, acceptance and support scope in the quotation. Contact +8801805987890 or info@vvon.com.bd.
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