{"entity":{"id":"tc-99m","kind":"isotope","name":"Technetium-99m","aka":["99mTc","Tc-99m"],"tldr":"The single most widely used medical radioisotope: a metastable metal with a six-hour lifetime, milked on demand from a bedside generator (a 'moly cow') and attached to a cold kit to image bone, heart, kidneys or lymph nodes.","summary":"Technetium-99m decays with a 6.0067-hour half-life, almost entirely by isomeric transition, emitting a 140.5 keV gamma ray that sits close to the energy of diagnostic X-ray equipment and is close to ideal for gamma-camera and SPECT imaging. It underpins on the order of tens of millions of scans a year worldwide (bone scans, myocardial perfusion, sentinel lymph node mapping, renal and hepatobiliary studies), each prepared on site by adding the eluted pertechnetate to a lyophilised cold kit.\n\nIt is the daughter of molybdenum-99 (65.94-hour half-life), which is shipped to hospital and radiopharmacy radiopharmacies worldwide as a 99Mo/99mTc generator; the longer-lived parent decays continuously and the daughter is eluted, typically once or twice a day, for use within hours before it decays away. This generator relationship is what makes just-in-time global distribution of a six-hour isotope possible at all.\n\nBecause supply of 99mTc is entirely downstream of 99Mo production, its reliability tracks the well-documented fragility of that upstream reactor supply chain (see mo-99): unplanned reactor outages, most recently the October 2024 shutdown of the High Flux Reactor in the Netherlands, have repeatedly caused short-notice shortages of Tc-99m-based scans.","status":"established","asOf":"2026-09-22","links":[{"label":"NNDC/LNHB: Tc-99m decay data tables","url":"http://www.lnhb.fr/nuclides/Tc-99m_tables.pdf"},{"label":"OECD/NEA: current trends in the supply and utilisation of medical radioisotopes (2025)","url":"https://www.oecd-nea.org/upload/docs/application/pdf/2025-10/7743_medical_radioisotopes_supply_rev.pdf"}],"tags":["gamma emitter","generator","most widely used"],"related":["technetium-sulfur-colloid","tilmanocept-tc99m","mo-99"],"indications":[],"sections":[],"technologies":["spect","spect-ct","radionuclide-generators-kits","research-reactor-isotope-production","nuclear-medicine-hardware"],"targets":[],"drugs":[],"companies":["curium","ge-healthcare","lantheus","cardinal-health"],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"symbol":"99mTc","element":"Technetium","massNumber":99,"halfLife":"6.0067 hours","emissions":["γ 140.5 keV (89%)","internal conversion electrons (~11% of decays)"],"emissionClass":"gamma","use":"imaging","production":"Eluted from a 99Mo/99mTc generator (the '99Mo/99mTc generator' or 'moly cow'); 99Mo is made by fission of enriched uranium targets in a research reactor or by neutron activation of enriched molybdenum-98.","supply":"tight","supplyNote":"Supply is set entirely by upstream 99Mo production; ageing research reactors and periodic unplanned outages (for example the HFR shutdown of October 2024) have caused recurrent short-notice Tc-99m shortages despite no direct constraint on technetium itself.","chelators":[],"pairedWith":[],"since":1964},"route":"/isotopes/tc-99m/","neighbours":{"drug":[{"id":"rb-82-chloride","kind":"drug","name":"Rubidium Rb-82 chloride","route":"/drugs/rb-82-chloride/"},{"id":"f-18-naf","kind":"drug","name":"Sodium fluoride F-18","route":"/drugs/f-18-naf/"},{"id":"technegas","kind":"drug","name":"Technegas (technetium Tc-99m labelled carbon inhalation aerosol)","route":"/drugs/technegas/"},{"id":"pexiretide-tc99m","kind":"drug","name":"Technetium (99mTc) pexiretide","route":"/drugs/pexiretide-tc99m/"},{"id":"tc-99m-maa","kind":"drug","name":"Technetium Tc-99m albumin aggregated (MAA)","route":"/drugs/tc-99m-maa/"},{"id":"tc-99m-mdp","kind":"drug","name":"Technetium Tc-99m medronate (MDP)","route":"/drugs/tc-99m-mdp/"},{"id":"tc-99m-psma-imaging","kind":"drug","name":"Technetium Tc-99m PSMA agents (PSMA-I&S)","route":"/drugs/tc-99m-psma-imaging/"},{"id":"tc-99m-pyrophosphate","kind":"drug","name":"Technetium Tc-99m pyrophosphate","route":"/drugs/tc-99m-pyrophosphate/"},{"id":"tc-99m-sestamibi","kind":"drug","name":"Technetium Tc-99m sestamibi","route":"/drugs/tc-99m-sestamibi/"},{"id":"technetium-sulfur-colloid","kind":"drug","name":"Technetium Tc-99m sulfur colloid","route":"/drugs/technetium-sulfur-colloid/"},{"id":"tc-99m-tetrofosmin","kind":"drug","name":"Technetium Tc-99m tetrofosmin","route":"/drugs/tc-99m-tetrofosmin/"},{"id":"tc-99m-hmpao-brain","kind":"drug","name":"Technetium-99m exametazime (brain perfusion)","route":"/drugs/tc-99m-hmpao-brain/"},{"id":"tilmanocept-tc99m","kind":"drug","name":"Technetium-99m tilmanocept","route":"/drugs/tilmanocept-tc99m/"},{"id":"tl-201-chloride","kind":"drug","name":"Thallous chloride Tl-201","route":"/drugs/tl-201-chloride/"},{"id":"y-90-resin-microspheres","kind":"drug","name":"Yttrium-90 resin microspheres","route":"/drugs/y-90-resin-microspheres/"}],"isotope":[{"id":"kr-81m","kind":"isotope","name":"Krypton-81m","route":"/isotopes/kr-81m/"},{"id":"mo-99","kind":"isotope","name":"Molybdenum-99","route":"/isotopes/mo-99/"}],"technology":[{"id":"cold-kit-formulation","kind":"technology","name":"Cold kit formulation","route":"/technologies/cold-kit-formulation/"},{"id":"gamma-probes-dose-calibrators","kind":"technology","name":"Gamma probes, handheld gamma cameras and dose calibrators","route":"/technologies/gamma-probes-dose-calibrators/"},{"id":"hot-cells-and-shielding","kind":"technology","name":"Hot cells and radiation shielding","route":"/technologies/hot-cells-and-shielding/"},{"id":"mo99-tc99m-generators","kind":"technology","name":"Molybdenum-99/technetium-99m generators","route":"/technologies/mo99-tc99m-generators/"},{"id":"nuclear-medicine-hardware","kind":"technology","name":"Nuclear medicine and total-body PET hardware","route":"/technologies/nuclear-medicine-hardware/"},{"id":"radionuclide-generators-kits","kind":"technology","name":"Radionuclide generators and cold kits","route":"/technologies/radionuclide-generators-kits/"},{"id":"research-reactor-isotope-production","kind":"technology","name":"Research reactors for medical isotopes (Mo-99, Lu-177, I-131)","route":"/technologies/research-reactor-isotope-production/"},{"id":"spect","kind":"technology","name":"SPECT & bone scan","route":"/technologies/spect/"},{"id":"spect-dosimetry-workflow","kind":"technology","name":"SPECT dosimetry workflow for radionuclide therapy","route":"/technologies/spect-dosimetry-workflow/"},{"id":"spect-ct","kind":"technology","name":"SPECT/CT","route":"/technologies/spect-ct/"},{"id":"therapy-isotope-supply-chain","kind":"technology","name":"Therapeutic isotope supply chain (Mo-99, Lu-177, Ac-225)","route":"/technologies/therapy-isotope-supply-chain/"}],"company":[{"id":"bwxt-medical","kind":"company","name":"BWXT Medical","route":"/companies/bwxt-medical/"},{"id":"cardinal-health","kind":"company","name":"Cardinal Health Nuclear & Precision Health Solutions","route":"/companies/cardinal-health/"},{"id":"curium","kind":"company","name":"Curium","route":"/companies/curium/"},{"id":"cyclopharm","kind":"company","name":"Cyclopharm","route":"/companies/cyclopharm/"},{"id":"ge-healthcare","kind":"company","name":"GE HealthCare","route":"/companies/ge-healthcare/"},{"id":"lantheus","kind":"company","name":"Lantheus","route":"/companies/lantheus/"},{"id":"navidea","kind":"company","name":"Navidea Biopharmaceuticals","route":"/companies/navidea/"},{"id":"niowave","kind":"company","name":"Niowave","route":"/companies/niowave/"},{"id":"quirem-medical","kind":"company","name":"Quirem Medical","route":"/companies/quirem-medical/"}],"indication":[{"id":"cardiac-amyloidosis-attr","kind":"indication","name":"Cardiac amyloidosis (transthyretin, ATTR-CM)","route":"/indications/cardiac-amyloidosis-attr/"},{"id":"coronary-artery-disease","kind":"indication","name":"Coronary artery disease","route":"/indications/coronary-artery-disease/"},{"id":"thyroid-nodule-assessment","kind":"indication","name":"Functional assessment of thyroid nodules","route":"/indications/thyroid-nodule-assessment/"},{"id":"gastrointestinal-bleeding","kind":"indication","name":"Gastrointestinal bleeding localisation","route":"/indications/gastrointestinal-bleeding/"},{"id":"graves-hyperthyroidism","kind":"indication","name":"Graves' disease and hyperthyroidism","route":"/indications/graves-hyperthyroidism/"},{"id":"nsclc","kind":"indication","name":"Non-small cell lung cancer","route":"/indications/nsclc/"},{"id":"infection-prosthetic-joint","kind":"indication","name":"Prosthetic joint infection","route":"/indications/infection-prosthetic-joint/"},{"id":"pulmonary-embolism-vq","kind":"indication","name":"Pulmonary embolism: ventilation/perfusion imaging","route":"/indications/pulmonary-embolism-vq/"},{"id":"sentinel-node-mapping","kind":"indication","name":"Sentinel lymph node mapping in breast cancer and melanoma","route":"/indications/sentinel-node-mapping/"},{"id":"renal-obstruction","kind":"indication","name":"Suspected upper urinary tract obstruction","route":"/indications/renal-obstruction/"}],"institution":[{"id":"asnc","kind":"institution","name":"American Society of Nuclear Cardiology","route":"/institutions/asnc/"},{"id":"jsnm","kind":"institution","name":"Japanese Society of Nuclear Medicine","route":"/institutions/jsnm/"}],"opportunity":[{"id":"opp-caix-indeterminate-renal-mass","kind":"opportunity","name":"CAIX imaging of the indeterminate renal mass","route":"/opportunities/opp-caix-indeterminate-renal-mass/"},{"id":"opp-ceacam5-imaging-colorectal","kind":"opportunity","name":"CEACAM5 imaging for occult colorectal recurrence","route":"/opportunities/opp-ceacam5-imaging-colorectal/"}],"bottleneck":[{"id":"b-enriched-target-material","kind":"bottleneck","name":"Enriched target material for therapeutic isotopes","route":"/bottlenecks/b-enriched-target-material/"},{"id":"b-mo99-supply","kind":"bottleneck","name":"Molybdenum-99 supply","route":"/bottlenecks/b-mo99-supply/"},{"id":"b-reimbursement-coding","kind":"bottleneck","name":"Reimbursement and coding for radiopharmaceuticals","route":"/bottlenecks/b-reimbursement-coding/"}],"section":[{"id":"f-cardiac-imaging","kind":"section","name":"Cardiac imaging","route":"/fronts/f-cardiac-imaging/"},{"id":"f-isotope-supply","kind":"section","name":"Isotope supply","route":"/fronts/f-isotope-supply/"},{"id":"f-regulation-reimbursement","kind":"section","name":"Regulation & reimbursement","route":"/fronts/f-regulation-reimbursement/"}],"roadmap":[{"id":"isotope-supply-roadmap","kind":"roadmap","name":"Isotope supply roadmap: reactor dependence → non-uranium production → accelerator-made actinium","route":"/roadmaps/isotope-supply-roadmap/"}],"target":[{"id":"bone-hydroxyapatite","kind":"target","name":"Bone mineral (hydroxyapatite)","route":"/targets/bone-hydroxyapatite/"},{"id":"cck2-receptor","kind":"target","name":"CCK2 receptor (gastrin receptor)","route":"/targets/cck2-receptor/"},{"id":"integrin-avb3","kind":"target","name":"Integrin αvβ3","route":"/targets/integrin-avb3/"}],"term":[{"id":"flare-phenomenon","kind":"term","name":"Flare phenomenon","route":"/terms/flare-phenomenon/"},{"id":"hot-lab","kind":"term","name":"Hot lab (radiopharmacy dispensing area)","route":"/terms/hot-lab/"},{"id":"release-criteria","kind":"term","name":"Product release criteria (radiopharmaceutical quality control)","route":"/terms/release-criteria/"},{"id":"radiochemical-purity","kind":"term","name":"Radiochemical purity (RCP)","route":"/terms/radiochemical-purity/"},{"id":"radionuclidic-purity","kind":"term","name":"Radionuclidic purity","route":"/terms/radionuclidic-purity/"},{"id":"extravasation-radiopharmaceutical","kind":"term","name":"Radiopharmaceutical extravasation","route":"/terms/extravasation-radiopharmaceutical/"},{"id":"radiopharmacy-term","kind":"term","name":"Radiopharmacy (practice and discipline)","route":"/terms/radiopharmacy-term/"}],"trial":[{"id":"aurora-flurpiridaz","kind":"trial","name":"AURORA","route":"/trials/aurora-flurpiridaz/"}]}}