Hot lab (radiopharmacy dispensing area)

A hot lab is the shielded workspace within a nuclear medicine department or radiopharmacy where unsealed radioactive materials are received, surveyed, assayed, compounded or drawn into unit doses, and staged for use or decay-in-storage disposal. It typically houses a dose calibrator (a shielded re-entrant ionisation chamber used to assay every dose before administration), an L-block workstation with leaded glass shielding, syringe and vial shields of lead or tungsten, a fume hood or laminar-flow cabinet for volatile or aseptic compounding, generator storage (for example Mo-99/Tc-99m generators), a decay-in-storage area for short-lived waste, and contamination survey and monitoring equipment. "Hot cell" refers more specifically to a heavily shielded enclosure, often with remote manipulators and lead-glass viewing windows, used to handle the highest-activity materials, such as commercial radiopharmaceutical production or generator processing, without direct manual contact.

Because the hot lab concentrates the highest activities handled anywhere in a facility, its physical design (shielding thickness, room layout, ventilation and workflow zoning) is calculated by a qualified expert, typically a board-certified medical physicist, based on the isotopes used, weekly workload, occupancy of adjacent areas, and distance to occupied space, with the design goal of keeping public exposure below the 10 CFR 20.1301 limits (2 mrem in any one hour, 100 mrem per year) and occupational exposure within ALARA. Regulatory requirements for the hot lab's instruments and procedures flow from 10 CFR Part 35 (dose calibrators under 35.60/35.63, survey instruments under 35.61, labelling of vials and syringes under 35.69, and daily/weekly area surveys under 35.70).

The hot lab is where most of the practical burden of radiopharmaceutical GMP and release sits: incoming shipment surveys, generator eluate testing for radionuclidic breakthrough, on-site kit preparation and quality control (radiochemical purity, pH, sterility as applicable under USP <825>), and the final dose-calibrator assay that confirms the activity to be given to each patient matches the prescription.