# Cold chain and time-critical logistics

Source: https://nuclide.cc/bottlenecks/b-cold-chain-logistics/  
Nuclide record `b-cold-chain-logistics` (Bottleneck). Data CC BY-NC 4.0, attribute "Data from Nuclide (nuclide.cc)"; commercial use needs a licence.

## TL;DR

Radioactive medicines keep losing strength from the moment they are made, so a doctor prescribes a specific amount to arrive at a specific time. If a flight is delayed, an airline refuses the cargo, or customs holds the package for even a few hours, the dose can decay below the amount a patient needs and has to be thrown away.

## Summary

Because radioactive decay cannot be paused, every radiopharmaceutical shipment is ordered as an activity calibrated to a specific date and time, with the manufacturer dispensing extra margin so the prescribed activity still holds when the patient is dosed. For the shortest-lived isotopes the arithmetic is unforgiving: molybdenum-99, with a 66-hour half-life, loses about 22% of its activity to a single day's transport delay. A missed delivery window is not simply a late shipment -- the product is unusable and cannot be replaced from any stockpile.

Most radiopharmaceutical shipments travel as Class 7 dangerous goods under IATA and national transport rules, on top of any temperature control (commonly 2-8°C) the specific product needs, and this dual compliance burden restricts which carriers and routes are available. Some major airlines refuse Class 7 cargo outright, individual pilots have refused loads once they see radioactive labelling, and flights that do accept it often cap the total transport index (radiation level) permitted per aircraft. A 2026 survey of six English-speaking Southern African Development Community countries found customs clearance delays of up to a day reported in South Africa, Zambia, Namibia, Tanzania and Mauritius, with reported order-to-delivery lead times ranging from a few days (regional generator shipments) to about a month for products sourced from further afield.

The IAEA and ICAO have responded with a formal denial-and-delay-of-shipment reporting mechanism and national focal points to track and resolve recurring blockages, and IATA now requires shippers to hold specific Class 7 certification, but the underlying constraint -- a short, physics-set delivery window intersecting with an inconsistent, carrier-by-carrier and country-by-country regulatory patchwork -- has not been resolved.

## Fields

- Kind: Bottleneck
- Last checked: 2026-09-22
- Tags: logistics; Class 7; cold chain; half-life
- Stage: access-delivery
- Severity: moderate
- Metrics: Activity lost to a one-day transport delay of molybdenum-99 (66-hour half-life): ~22%; Reported radiopharmaceutical order-to-delivery lead times across surveyed SADC countries: range: a few days to ~1 month; Customs clearance delays reported for radiopharmaceutical imports: up to ~1 day, in multiple surveyed countries
- Causes: Radioactive decay is continuous and irreversible, so there is no buffer stock to fall back on if a shipment is delayed anywhere in the chain.; Radiopharmaceuticals must simultaneously meet Class 7 radioactive-material transport rules and, for many products, refrigerated cold-chain requirements, a combination few carriers are equipped or willing to handle.; Some airlines and individual crews decline Class 7 cargo outright, narrowing available routes, and remaining carriers cap how much transport-index (radiation level) cargo they will carry per flight.; Customs procedures for radioactive material are inconsistently applied across countries, and staff at many border posts have limited familiarity with the specific documentation required.

## Sources

- INMM PATRAM 2010: Transport of radiopharmaceuticals, cradle to the patient: https://resources.inmm.org/system/files/patram_proceedings/2010/233_Paper_TRANSPORT-OF-RADIOPHARMACEUTICALS,-CRADLE-TO-THE-P.pdf
- Challenges in radiopharmaceutical importation across six SADC countries (2026): https://pmc.ncbi.nlm.nih.gov/articles/PMC13002445/
- ICAO Assembly working paper on denial and delay of shipment of radioactive material: https://www.icao.int/sites/default/files/Meetings/a42/Documents/WP/wp_439_en.pdf
- Radiopharmaceutical supply chain structure (MedRaySintell): https://medraysintell.com/radiopharmaceutical-supply-chain-structure-7-7/

## Connected records

- ideas: [Regional radiopharmacy hubs and harmonised transport rules for short-lived isotopes](https://nuclide.cc/ideas/idea-reg-regional-radiopharmacy-hubs/)
- bottlenecks: [Molybdenum-99 supply](https://nuclide.cc/bottlenecks/b-mo99-supply/), [Site readiness and referral pathway delays](https://nuclide.cc/bottlenecks/b-site-readiness-referral/)
- isotopes: [Molybdenum-99](https://nuclide.cc/isotopes/mo-99/)
- technologies: [PET tracer manufacturing and distribution](https://nuclide.cc/technologies/pet-tracer-manufacturing/), [Radiopharmacy and cyclotron networks](https://nuclide.cc/technologies/radiopharmacy-network/), [Therapeutic isotope supply chain (Mo-99, Lu-177, Ac-225)](https://nuclide.cc/technologies/therapy-isotope-supply-chain/)

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