Medical Physicist's Notes · Display Unit
Five typical clusters,and the rules that decide each one.
Cluster planning is the design choice that decides 60-80 % of the RMS cable budget and most of the future-expansion flexibility. This post walks five typical clusters at a cyclotron / PET / theranostic facility, the rules that map detectors into them, and the standard-vs- ruggedised variant choice for each.
Five typical clusters
Where the display unit sits and what it aggregates
| Cluster | Typical detectors | Ruggedised? | Example site |
|---|---|---|---|
| Vault corridor | Area gamma × 2 + neutron × 1 + (optional) interlock-door panel | Yes — corridor environment | Most cyclotron facilities deploy this cluster as the first one |
| Hot lab quadrant | Area gamma × 2 around dispensing bench + 1 at dose-calibrator + 1 at QC station | No — clean climate-controlled environment | PET production hot labs, theranostic dispensing labs |
| Theranostic ward | Area gamma × 4 — one outside each patient room | No — corridor environment | Lu-177 / I-131 inpatient wards |
| Egress + exhaust | Hand-foot frisker + stack monitor + 2 area gamma | Mixed — frisker indoor, others may need rugged | Combined egress + facility-perimeter cluster |
| Outdoor perimeter | Area gamma × 4 — perimeter posts around the building | Yes — outdoor exposure | Facilities with public-area dose-rate documentation requirements |
Planning rules
Five rules that decide cluster mapping
- Map detectors to clusters by physical proximity, not by detector type. The display unit aggregates four detectors regardless of type — neutron + gamma + contamination can sit in the same cluster if they share a corridor.
- Long-haul cable cost dominates the budget. The cluster topology saves cable runs, conduit installation and patch-panel ports — typical savings 60-80 % vs direct-to-server cabling at a multi-cluster facility.
- Reserve one spare slot per cluster. When the facility adds a new monitor a year later (a new clean-room boundary monitor, an inspector-requested perimeter point), it joins the existing cluster — no new cable run, no central reconfiguration.
- Don't mix indoor and outdoor in the same cluster unless the display unit lives indoors. The standard variant doesn't survive long-term outdoor exposure; the ruggedised variant does.
- Co-locate the display unit with the local team that uses it — radiopharmacist at the hot-lab cluster, nurse station at the ward cluster, security at the perimeter cluster. The display is doing situational-awareness work locally; the RMS server is doing the inspection-grade archive.
Standard vs ruggedised
When to specify the ruggedised variant
- Vault corridor: temperature swings during cyclotron production runs, occasional cooling-system condensate. Use ruggedised.
- Hot-lab clean room: climate-controlled clean environment. Standard unit is fine.
- Theranostic ward corridor: hospital climate, occasional cleaning-fluid spray. Standard unit, mounted out of spray range.
- Egress lane: high-traffic area, occasional knocks. Standard unit; mount above operator-hand height.
- Outdoor perimeter shed: dust, humidity, temperature extremes. Use ruggedised in an outdoor enclosure.
- Hot-lab boundary at the gowning interface: ruggedised because the boundary sees occasional cleaning-fluid spray during clean-room turn-over.