The platform: gantry boards, X-ray chain, DMS and data path, couch, console, power and cooling

Name the main assemblies and control boards of the NeuViz 16 and NeuViz 128, say which unit talks to which and over what link, and follow the data from the detector to the image.

Two scanners, one family, different documents

This course covers two members of the NeuViz family. The NeuViz 16 is the older 16-slice scanner. Its troubleshooting manual was issued by Philips and Neusoft Medical Systems, and on the console the application is still launched under an MX 16-slice name, a sign of its shared history with the Philips MX16 platform (an FDA recall notice also names the MX 16-slice console software). The NeuViz 128 is the later scanner; its calibration manual is a Neusoft document. Its FDA 510(k) record describes a whole-body scanner with a 64-row solid-state detector, a 72 cm bore and up to 128 slices per rotation: the 128 counts slices, not detector rows, and the scanner uses a flying focal spot.

You will meet both scanners in the field, often in the same region and sometimes under a local brand name. Do not assume a board, a code or a limit from one applies to the other. In this course every model-specific statement says which document it comes from. When you work on a NeuViz 64, a NeuViz Prime or another variant, use its own documentation; the logic transfers, the details do not.

One practical consequence of the shared ancestry: when a NeuViz 16 document is silent, engineers sometimes look in MX16 material. That can help you understand a design, but it is not an authority for values, lubricants or procedures on a NeuViz. Ask the manufacturer or its authorised service organisation and record where the answer came from.

The gantry is a network of controllers

The most useful picture of a NeuViz 16 gantry is not mechanical but logical. The stator control board is the master of the stationary side. It drives tilt, supervises rotation, reads the tilt potentiometer, watches the front cover, door and mains supervision inputs, and shows its state on a small four-character display. That display is your first diagnostic tool: a ready indication when all is well, codes beginning with Er for errors that flash twice in two seconds, and codes beginning with n for warnings that flash once in two seconds. Each code maps to a system error number that also appears in the console log.

The other units hang off a CAN network: the left and right gantry control panels, the patient table motion control board, the CTBOX and, across the slip ring, the rotor control board. Each of them carries a small UCOM interface board. Its LEDs tell you whether the CAN, SPI and flash ports are healthy, whether a monitored supply has failed, whether the unit runs its normal or backup firmware, and which CAN address it believes it has. A unit with the wrong address, or a panel plugged into the table CAN port, will produce communication time-outs that look like a dead board.

On the rotor, the rotor control board is the local master. It commands the HV generator (contactor, starter, grid, HV on, no-load test mode), moves the collimator, follows the focus, receives couch and integration-period pulses and talks to the detector electronics. Its LEDs show slip ring link faults, CRC errors on received commands, and A-plane errors such as slice width, Z position, filter or focus follow. Above these boards sit two computers named in the logs: the gantry host, called G-Host or GPC, and the R-Host that handles the DMS side, both talking to the console host.

X-ray chain: generator, tube and A-plane

The NeuViz 16 manual describes two HV generator variants, an X3815 chassis and a Fironia-50, with separate troubleshooting charts for each. Know which one you have before you open a chart, because test points, boards and fault names differ. Functionally both have the same blocks: a mains-side AC/inverter box, an HV box with the tank, the system control board inside the generator, and the anode starter that spins the rotating anode. Faults are reported in groups you will meet in lesson 4: arcs, anode or cathode overvoltage, filament, inverter temperature, kV and mA regulation, cathode overcurrent and starter.

The collimator on these scanners is called the A-plane. It holds the blades that set slice thickness, a compensator (the beam-shaping filter) and the mechanics that move them: step motors with their drivers, encoders and optical sensors that report slice thickness, slice position and compensator position, plus a Z-direction detection board used to keep the beam on the detector as the focal spot moves. On the NeuViz 128 the calibration manual adds mechanical pre-adjustment of the A-plane with a dial gauge and alignment of the tube in X and Z, which tells you how sensitive the beam geometry is to mechanical work.

The tube oil carries heat to a heat exchanger on the rotor (check the cooling design of your model in its service manual), and the HV prepare sequence checks the tube temperature and oil flow switch before it lets the contactor close. Treat that switch as a protection, not as a nuisance.

DMS and the data path across the slip ring

The detector measurement system, DMS, is the detector array with its acquisition electronics. On the NeuViz 16 the manual shows 42 detector modules feeding an RCOM board, with temperature control on two channels and a reference detector. There are two RCOM types, for DMS-GNP and DMS-DPN, with different LED layouts, so identify yours first. The RCOM collects the readings, and its LEDs show supply rails, bias and data making during a scan, and the reading rate.

From the RCOM the readings go by optical fibre to a transmitter box on the rotor, cross the slip ring by a radio-frequency link to a receiver box on the stator, and continue by fibre to the DRC board in the console host. The DRC acknowledges good readings with a toggling Comm_OK signal, and the RCOM resends what was not acknowledged. That resend mechanism is why a marginal link may first appear as slow or intermittent scans before it becomes a hard error. The transmitter and receiver boxes each show a power LED and a signal LED; both off means fault.

On the NeuViz 128 the calibration manual names further DMS parts that trigger calibrations when replaced: the film heating assembly and temperature control board of the DMS, the reference detector, a reference box and an iHD unit. We do not have the NeuViz 128 hardware description, so treat these names as pointers to its own service manual.

Couch, console, power and environment

The couch has a horizontal servo drive (the NeuViz 16 manual lists two servo amplifier types with their own code tables), a vertical drive with a height encoder, limit and zero switches, a float or release function for moving the top by hand, and foot pedals. On the NeuViz 128 the horizontal stroke is guarded by front and rear limit switches, a rear safety switch that must be pressed before the top can be lowered below the down position, and a zero switch that resets the horizontal position count. A 300 kg table version exists with its own load test. The gantry tilts by a motor with a potentiometer feedback and two limit switches.

The console host runs the application, the database, reconstruction and the error log viewer. On the NeuViz 16 the scan-start chart checks two disk areas separately: image data and raw data. Disks may sit in a RAID set, which matters when someone wants to rearrange them. Power is distributed by a power control board whose LEDs report power, emergency stop chain, voltage supervision, door switch, fans, X-ray ready and X-ray on. These seven LEDs answer many 'gantry will not start' calls before you open anything else, but they are diagnostic indicators, not proof that a circuit is dead.

Room temperature and humidity, the tube heat exchanger, the detector temperature and the console cooling all affect image quality and part life. The values for the room come from the manufacturer's site planning documentation; the detector temperature window used by the NeuViz 16 scan-start check is covered in lesson 4.

On-site checklist

• Model, serial number and software version recorded
• HV generator variant identified (NeuViz 16: X3815 or Fironia-50)
• DMS and RCOM type identified
• Stator display state and power control board LEDs noted before any action
• Applicable service, calibration and safety documents at hand for this model

Check yourself