# Molybdenum-99

Source: https://nuclide.cc/isotopes/mo-99/  
Nuclide record `mo-99` (Isotope). Data CC BY-NC 4.0, attribute "Data from Nuclide (nuclide.cc)"; commercial use needs a licence.

## TL;DR

The parent isotope shipped worldwide to make technetium-99m, the gamma-ray tracer used in the majority of nuclear medicine scans. It is made in a handful of ageing research reactors, and when one breaks down, scans get delayed or cancelled.

## Summary

Molybdenum-99 decays with a 65.94-hour (about 2.75-day) half-life to technetium-99m, and its whole purpose in the supply chain is to act as a transportable parent: its longer half-life lets bulk 99Mo be irradiated, processed and shipped internationally to radiopharmacies, which then load it into 99Mo/99mTc generators and elute the six-hour daughter locally, on demand, for the roughly tens of millions of Tc-99m scans performed worldwide each year.

Historically some 90-95% of global 99Mo came from just five ageing research reactors, three in Europe (BR2 in Belgium, HFR in the Netherlands, and the now-closed OSIRIS in France), one in Canada (the now-closed NRU) and one in South Africa (SAFARI-1); by the OECD/NEA's 2025 accounting the surviving fleet, including BR2 and HFR, remains dominated by reactors that were not designed for continuous isotope production and were commissioned in the mid-20th century, so unplanned outages are a recurring risk: an October 2024 structural fault forced an unplanned shutdown of the HFR, which combined with scheduled maintenance elsewhere to worsen shortages of both 99Mo and 99mTc that winter.

The other defining event of the last fifteen years has been the conversion from highly enriched uranium (HEU, historically 45-98% 235U) fission targets to low-enriched uranium (LEU, under 20% 235U) for non-proliferation reasons: Curium's Netherlands processing facility completed conversion in January 2018, and IRE (Belgium) completed its conversion in March 2023, after which the OECD/NEA estimated that more than 90% of global bulk 99Mo production capacity came from non-HEU sources. LEU targets are less efficient and generate more waste per curie produced, and the industry's underlying economic problem, according to repeated OECD/NEA studies, is that irradiation and processing prices have historically been too low to fund the reactor and processing capacity replacement the ageing fleet needs; the 2010 NEA economic study estimated irradiation-service prices would need to rise by up to roughly a factor of nine to be sustainable. New non-fission routes are diversifying supply: NorthStar's RadioGenix System, which produces 99Mo by neutron activation of enriched or natural molybdenum targets rather than uranium fission, reached commercial scale in the 2020s (though NorthStar separately announced in 2023 a temporary halt to one production line), and Australia's ANSTO and South Africa's NTP Radioisotopes remain major LEU-fission suppliers outside the historic European/Canadian core.

## Fields

- Kind: Isotope
- Status: established
- Last checked: 2026-09-22
- Also known as: 99Mo; Mo-99
- Tags: beta emitter; generator parent; reactor supply chain; ageing infrastructure

## Sources

- OECD/NEA: current trends in the supply and utilisation of medical radioisotopes (2025): https://www.oecd-nea.org/upload/docs/application/pdf/2025-10/7743_medical_radioisotopes_supply_rev.pdf
- OECD/NEA: the security of supply of medical radioisotopes, 2023-2027 demand and capacity projections: https://www.oecd-nea.org/upload/docs/application/pdf/2023-10/nea_ndc_r_2023_1.pdf
- OECD/NEA: an economic study of the molybdenum-99 supply chain: https://www.oecd-nea.org/med-radio/reports/MO-99.pdf

## Connected records

- isotopes: [Technetium-99m](https://nuclide.cc/isotopes/tc-99m/)
- drugs: [Technetium Tc-99m sulfur colloid](https://nuclide.cc/drugs/technetium-sulfur-colloid/), [Technetium-99m tilmanocept](https://nuclide.cc/drugs/tilmanocept-tc99m/)
- technologies: [Cold kit formulation](https://nuclide.cc/technologies/cold-kit-formulation/), [Molybdenum-99/technetium-99m generators](https://nuclide.cc/technologies/mo99-tc99m-generators/), [Radiolabelling quality control](https://nuclide.cc/technologies/radiolabelling-quality-control/), [Radionuclide generators and cold kits](https://nuclide.cc/technologies/radionuclide-generators-kits/), [Research reactors for medical isotopes (Mo-99, Lu-177, I-131)](https://nuclide.cc/technologies/research-reactor-isotope-production/), [SPECT & bone scan](https://nuclide.cc/technologies/spect/), [Therapeutic isotope supply chain (Mo-99, Lu-177, Ac-225)](https://nuclide.cc/technologies/therapy-isotope-supply-chain/)
- companies: [ANSTO (Australian Nuclear Science and Technology Organisation)](https://nuclide.cc/companies/ansto/), [Atomic Alchemy](https://nuclide.cc/companies/atomic-alchemy/), [BWXT Medical](https://nuclide.cc/companies/bwxt-medical/), [China Isotope & Radiation Corporation](https://nuclide.cc/companies/china-isotope-radiation/), [Curium](https://nuclide.cc/companies/curium/), [IRE (Institut national des Radioéléments)](https://nuclide.cc/companies/ire/), [Niowave](https://nuclide.cc/companies/niowave/), [Nordion (Sotera Health)](https://nuclide.cc/companies/nordion/), [NorthStar Medical Radioisotopes](https://nuclide.cc/companies/northstar-medical-radioisotopes/), [NTP Radioisotopes](https://nuclide.cc/companies/ntp-radioisotopes/), [SHINE Technologies](https://nuclide.cc/companies/shine-technologies/)
- ideas: [A coordinated reserve and shared schedule for the world's medical isotope reactors](https://nuclide.cc/ideas/idea-reg-medical-isotope-reactor-reserve/)
- institutions: [Board of Radiation and Isotope Technology](https://nuclide.cc/institutions/brit/), [Japanese Society of Nuclear Medicine](https://nuclide.cc/institutions/jsnm/)
- bottlenecks: [Cold chain and time-critical logistics](https://nuclide.cc/bottlenecks/b-cold-chain-logistics/), [Enriched target material for therapeutic isotopes](https://nuclide.cc/bottlenecks/b-enriched-target-material/), [Molybdenum-99 supply](https://nuclide.cc/bottlenecks/b-mo99-supply/), [Reimbursement and coding for radiopharmaceuticals](https://nuclide.cc/bottlenecks/b-reimbursement-coding/)
- fronts: [Isotope supply](https://nuclide.cc/fronts/f-isotope-supply/), [Regulation & reimbursement](https://nuclide.cc/fronts/f-regulation-reimbursement/)
- roadmaps: [Isotope supply roadmap: reactor dependence → non-uranium production → accelerator-made actinium](https://nuclide.cc/roadmaps/isotope-supply-roadmap/)
- terms: [Hot lab (radiopharmacy dispensing area)](https://nuclide.cc/terms/hot-lab/), [Product release criteria (radiopharmaceutical quality control)](https://nuclide.cc/terms/release-criteria/), [Radionuclidic purity](https://nuclide.cc/terms/radionuclidic-purity/), [Radiopharmacy (practice and discipline)](https://nuclide.cc/terms/radiopharmacy-term/)

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