Radiopharmacist's Notes · Hand-Foot Monitor

Six steps between a positive frisk and a signed-clean egress.

The first instinct on a positive frisk is to wash and re-frisk. The right instinct is to stay at the unit, notify, and decontaminate under supervision. This post walks the six-step escalation flow, how to set the per-isotope thresholds, and what the AERB inspection log reads off the RMS-fed egress record.

The six-step escalation

From first alarm to signed egress

1

First positive frisk

Stay at the unit. Don't leave the egress lane.

Walking out spreads the contamination into the corridor — the precise outcome the frisker exists to prevent.
2

Identify the surface

Use the unit's positive-detector indication (or the detachable hand probe) to identify exactly which hand, foot or clothing area is contaminated.

Precise localisation reduces decontamination time and avoids un-needed glove / clothing changes.
3

Notify radiation safety

Use the egress-lane phone or the RMS-driven alarm escalation to notify the RSO immediately.

The frisker streams the alarm to the RMS server; the RSO is already alerted. The operator confirms and stays on the lane.
4

Wash and re-frisk

Hand or foot: wash at the egress sink (warm water, mild detergent, no abrasive scrub). Clothing: change into the spare gown stored at the egress.

Hot wash, hard scrub or alcohol use can fix the contamination to the skin — the SOP is mild detergent only.
5

Repeat measurement

Re-frisk. If the reading is now below the threshold, sign the egress log and exit normally.

The unit records the second measurement automatically and appends the wash-and-retry annotation if configured.
6

Persistent contamination

If still positive after washing: stop. Do not attempt further decontamination unsupervised. Wait for the RSO to take over the response.

Persistent contamination on bare skin may indicate transcutaneous absorption; the RSO controls the bioassay and follow-up dose-assessment pathway.

Source: IAEA Safety Reports Series 40 — Operational Radiation Protection in Nuclear Medicine; AERB Safety Code for Nuclear Medicine Facility.

Threshold setting

Per-isotope presets the unit stores

The frisker threshold is set per-isotope (the unit supports stored presets). A site dispensing Tc-99m only can set a tighter threshold than a site also dispensing high-energy Lu-177 / Y-90 where the natural egress background is higher.
AERB Safety Code expects egress contamination thresholds compatible with the contamination-control framework — typically Bq/cm² values per isotope class.
The threshold is a configuration of the device, not a one-time setting. When the radiopharmacy adds a new isotope (e.g. introduces Lu-177 alongside an existing Tc-99m service), the threshold preset for that isotope is added.
Threshold changes are logged on the audit trail and feed into the AERB facility-inspection dossier alongside the egress log.

Inspection log

What AERB inspection actually reads

The egress log streams to the central RMS server: one line per egress, with date, time, operator (if RFID badge configured), isotope preset, measurement result and any wash-and-retry annotation.
During AERB inspection, the inspector typically asks for the egress log across the inspection window. The RMS export is the answer — no reactive log assembly during the visit.
A positive frisk followed by a wash-and-clear is not an incident; it's a working contamination-control system. A positive frisk followed by an exit is — and the absence of the second measurement on the log is what the inspector flags.
Annual contamination-control programme review (typical for AERB-licensed sites): pull the frisker log, summarise positive-frisk events by month and by isotope, note repeating-operator patterns and recommend SOP / training updates.