Nuclide
Isotopes & agents

Technology dependency map

44 technologies joined by 59 recorded dependencies in 6 layers. 9 foundations need nothing else in the corpus; 14 end products are needed by nothing further. Pick a root to see what one technology cannot exist without, and what stops if it fails.

44 technologies, 59 dependencies, 6 layers. Scroll to pan; hover a tile to trace what it needs and what needs it; click to open its page.

Layer 0 · foundationsLayer 1Layer 2Layer 3Layer 4Layer 5 · end productsCT (computed tomography) Depends on 0 · needed by 1 · 4 vendors A CT scan is a fast 3D X-ray that shows the size and shape of tumours and whether they have spread.CT (computed tomography)Cyclotron isotope production (F-18, Ga-68, Cu-64, Zr-89, At-211) Depends on 0 · needed by 6 · 15 vendors Proton-rich isotopes for PET scans and some therapies are made by hitting a target with a beam from a cyclotron. Fluorine-18 is made every morning within driving distance of the scanner; gallium-68 comes from either a generator or a cyclotron; copper-64 and zirconium-89 last long enough to ship across a country.Cyclotron isotope product…Chokepoint: removing this step cuts off part of the mapQuantitative imaging biomarkers (RECIST, PERCIST, SUV, ADC) Depends on 0 · needed by 1 The numbers pulled from scans that decide whether a cancer is shrinking, growing or dead: tumour diameters for RECIST, sugar uptake on PET, water movement on MRI; they run every trial and most clinic decisions, and they are only as good as the way the scan was taken.Quantitative imaging biom…Medical cyclotrons, hot cells, and synthesis modules Depends on 0 · needed by 4 · 5 vendors The particle accelerators and shielded robotic chemistry boxes that make PET tracers in hospital basements and commercial pharmacies.Medical cyclotrons, hot c…Therapeutic isotope supply chain (Mo-99, Lu-177, Ac-225) Depends on 0 · needed by 4 · 14 vendors Where the radioactive atoms for imaging and therapy actually come from: ageing reactors, new accelerators, and a scramble for actinium.Therapeutic isotope suppl…Research reactors for medical isotopes (Mo-99, Lu-177, I-131) Depends on 0 · needed by 1 · 13 vendors Most of the world's therapeutic and scanning isotopes are made by putting targets into about half a dozen ageing research reactors and flying the product out within days. When two reactors were down at once in 2009 and 2010, hospitals worldwide ran short of the most used scan isotope.Research reactors for med…Nuclear medicine and total-body PET hardware Depends on 0 · needed by 2 · 5 vendors Nuclear medicine hardware means the scanners themselves: PET/CT, SPECT/CT, and new total-body PET that images the whole body at once.Nuclear medicine and tota…Radionuclide generators and cold kits Depends on 0 · needed by 2 · 8 vendors Bench-top devices that 'milk' a short-lived isotope from a long-lived parent, plus vials of ready-to-label ligand. How most hospitals make PSMA and somatostatin PET tracers without a cyclotron.Radionuclide generators a…SPECT/CT Depends on 0 · needed by 1 · 3 vendors A gamma camera with a CT scanner bolted on, so a hot spot on a bone scan or a sentinel-node scan is pinned to the exact bone or lymph node, and the dose from a radioactive drug can be measured after treatment.SPECT/CTAutomated synthesis modules Depends on 2 · needed by 2 A shielded robotic 'chemistry-in-a-box' machine mixes and purifies radioactive drugs behind thick walls, so staff never have to handle dangerous, highly radioactive liquids by hand.Automated synthesis modul…Chokepoint: removing this step cuts off part of the mapMacropa chelation Depends on 1 · needed by 1 Macropa is a newer ring-shaped molecule built specifically to grip large radioactive metal atoms, such as the alpha-emitter actinium-225, quickly and at room temperature, which older molecules like DOTA cannot do well.Macropa chelationPET tracer manufacturing and distribution Depends on 1 · needed by 1 · 7 vendors Making PSMA, FDG, and new tracers under drug-manufacturing rules and delivering them daily.PET tracer manufacturing…Sarcophagine chelation Depends on 1 · needed by 1 Sarcophagine is a cage-shaped molecule that locks copper atoms inside so tightly that the copper cannot escape once the imaging or treatment dose is made, even inside the body.Sarcophagine chelationRadio-antibody & radio-ADC Depends on 1 · needed by 1 · 3 vendors Attaching a radioactive atom to an antibody, so an ADC's targeting is used to deliver radiation instead of chemotherapy.Radio-antibody & radio-ADCRadiopharmacy and cyclotron networks Depends on 1 · needed by 4 · 7 vendors The factories and courier routes that make and deliver short-lived radioactive tracers to hospitals within hours.Radiopharmacy and cyclotr…Molybdenum-99/technetium-99m generators Depends on 1 · needed by 1 A shielded column device lets hospitals 'milk' the world's most-used medical radioisotope, technetium-99m, fresh every day from a longer-lived parent isotope that is shipped to them from a reactor.Molybdenum-99/technetium-…Chokepoint: removing this step cuts off part of the mapSPECT & bone scan Depends on 2 · needed by 1 · 6 vendors SPECT and the bone scan are an older type of nuclear scan, still used for bone metastases and to check where a radioactive drug went after treatment.SPECT & bone scanQuantitative SPECT Depends on 1 · needed by 2 Modern gamma-camera scans can now be turned into maps of exactly how much radioactivity (in becquerels) sits in each part of the body, not just a picture, which is what lets doctors calculate a real radiation dose to a tumour or organ.Quantitative SPECTChokepoint: removing this step cuts off part of the mapHot cells and radiation shielding Depends on 1 · needed by 1 Radioactive drugs are made and handled behind thick walls of lead, tungsten or concrete inside sealed, negative-pressure boxes with built-in robot arms, so the radiation stays contained and staff outside stay safe.Hot cells and radiation s…PET (positron emission tomography) Depends on 2 · needed by 2 · 3 vendors A scan that shows where a radioactive tracer accumulates, so it images what tumours are doing rather than what they look like.PET (positron emission to…Chokepoint: removing this step cuts off part of the mapPretargeted radioimmunotherapy Depends on 2 · needed by 0 Instead of attaching radioactivity directly to a slow-moving antibody, doctors first inject the antibody alone, let it find the tumour and clear from the blood over some days, then inject a small fast-clearing radioactive tag that clicks onto the antibody only where it has stuck to the tumour.Pretargeted radioimmunoth…DOTA chelation Depends on 2 · needed by 2 DOTA is a small ring-shaped molecule that grips a radioactive metal atom tightly inside its cage, so the metal stays attached to the drug instead of drifting off into the body.DOTA chelationChokepoint: removing this step cuts off part of the mapCold kit formulation Depends on 2 · needed by 2 Many everyday radioactive scan drugs come as a freeze-dried powder in a sealed vial; the hospital pharmacy just adds the freshly produced radioactive solution and the finished injectable drug forms in minutes, no chemistry lab required.Cold kit formulationChokepoint: removing this step cuts off part of the mapRadioligand dosimetry Depends on 1 · needed by 2 Measuring, from scans taken after each dose, how much radiation a radioligand actually delivers to the tumour and to kidneys and marrow, so treatment can be personalised.Radioligand dosimetryMonte Carlo dosimetry Depends on 1 · needed by 1 Powerful computer simulations trace millions of individual particles of radiation as they fly through a virtual copy of a patient's body, giving the most detailed and realistic estimate of exactly how much radiation dose each organ and tumour actually receives.Monte Carlo dosimetryPET/MRI Depends on 1 · needed by 0 · 3 vendors PET combined with MRI instead of CT, giving biology plus the best soft-tissue detail, at lower radiation dose.PET/MRIAlbumin-binder ligands Depends on 1 · needed by 0 Attaching a small chemical 'hook' that grips the body's own albumin protein makes a radioactive drug stay in the bloodstream for longer, so more of it reaches the tumour before it is cleared out through the kidneys.Albumin-binder ligandsPET/CT Depends on 2 · needed by 6 · 5 vendors PET and CT in one machine, so hot spots on the PET are pinned to exact locations on the CT.PET/CTChokepoint: removing this step cuts off part of the mapRadiohybrid (rh) chemistry Depends on 2 · needed by 0 A radiohybrid molecule carries two possible attachment points, one for a fast PET-friendly radioactive fluorine tag and one for a radioactive metal used for treatment, so the imaging and treatment versions of the drug are chemically identical twins.Radiohybrid (rh) chemistryGermanium-68/gallium-68 generators Depends on 1 · needed by 1 A compact column loaded with a long-lasting parent isotope lets a PET radiopharmacy produce fresh gallium-68, used in scans such as PSMA and DOTATATE PET, on demand without needing a cyclotron.Germanium-68/gallium-68 g…Radiolabelling quality control Depends on 2 · needed by 0 Before any radioactive drug is given to a patient, a quick chemistry test checks that the radioactive atom is properly and completely attached to the drug molecule, rather than floating free, because free radioactivity goes to the wrong place in the body.Radiolabelling quality co…Targeted alpha therapy Depends on 3 · needed by 2 · 19 vendors Like radioligand therapy but with alpha particles: far more destructive over a much shorter range, so single cells can be killed with less collateral damage.Targeted alpha therapySPECT dosimetry workflow for radionuclide therapy Depends on 2 · needed by 0 After a radioactive treatment injection, patients are scanned two or three times over about a week so doctors can calculate exactly how much radiation dose the tumour and organs like the kidneys actually received, and adjust future doses if needed.SPECT dosimetry workflow…FDG PET Depends on 1 · needed by 0 FDG PET is the standard PET scan. A radioactive sugar shows which tissues are burning glucose fast, which most cancers do.FDG PETPSMA PET Depends on 2 · needed by 1 · 5 vendors A prostate-cancer-specific PET scan that finds spread far earlier than CT or bone scan, and tells you whether a matched radioactive drug will work.PSMA PETChokepoint: removing this step cuts off part of the mapRadioligand therapy (beta emitters) Depends on 5 · needed by 2 · 16 vendors A drug that finds tumour cells and carries a radioactive atom that irradiates them from inside the body.Radioligand therapy (beta…Somatostatin receptor PET (68Ga/64Cu-DOTATATE) Depends on 2 · needed by 1 · 1 vendor A PET scan using a radioactive hormone mimic that lights up neuroendocrine tumours and shows whether the matching radioactive treatment will work.Somatostatin receptor PET…Single vendor1Immuno-PET Depends on 1 · needed by 0 PET scans built from radiolabelled antibodies or their fragments, to see any protein an antibody can reach, including immune cells inside tumours.Immuno-PETStrontium-82/rubidium-82 generators Depends on 2 · needed by 0 A generator produces a very short-lived radioactive potassium-like tracer on demand at the bedside, allowing a heart PET scan to be finished in minutes without needing an on-site cyclotron.Strontium-82/rubidium-82…Alpha-emitter daughter redistribution ('free daughter' problem) Depends on 2 · needed by 0 When an alpha-emitting radioactive drug decays inside the body, the recoil kick is so strong that the leftover radioactive fragment breaks loose from the drug and can drift to organs like the kidneys, causing side effects the original drug was never meant to cause.Alpha-emitter daughter re…Astatine-211 alpha therapy Depends on 2 · needed by 0 · 1 vendor A rare alpha-emitting halogen that can be attached to antibodies and small molecules like iodine, tested in leukaemia conditioning and brain and ovarian cancer.Astatine-211 alpha therapySingle vendor1AI in nuclear medicine Depends on 2 · needed by 0 Computer software trained on thousands of scans can now automatically outline tumours on PET and SPECT images in seconds instead of the 30-45 minutes it takes a doctor, though a specialist still checks the result.AI in nuclear medicineLutetium-177 radioligand therapy Depends on 2 · needed by 0 Cancer-seeking molecules carrying the radioactive metal lutetium-177, which delivers short-range radiation to tumours it binds; approved for neuroendocrine tumours and prostate cancer.Lutetium-177 radioligand…Peptide receptor radionuclide therapy (PRRT) Depends on 2 · needed by 0 · 6 vendors A radioactive version of the hormone mimic used for the scan; it homes to neuroendocrine tumour cells and irradiates them from inside.Peptide receptor radionuc…

Chokepoints9

A chokepoint is a step whose removal splits the map: technologies downstream lose their only route to the foundations. These are where a recall, a plant fire or an export control does the most damage.

Automated synthesis modules2 direct dependents · 0 vendorsCold kit formulation2 direct dependents · 0 vendorsCyclotron isotope production (F-18, Ga-68, Cu-64, Zr-89, At-211)6 direct dependents · 15 vendorsDOTA chelation2 direct dependents · 0 vendorsMolybdenum-99/technetium-99m generators1 direct dependents · 0 vendorsPET (positron emission tomography)2 direct dependents · 3 vendorsPET/CT6 direct dependents · 5 vendorsPSMA PET1 direct dependents · 5 vendorsQuantitative SPECT2 direct dependents · 0 vendors

Single-vendor steps2

Steps with exactly one vendor company in the corpus. Some are genuinely sole-source; others just need more companies recorded, so treat this as a list to check rather than a verdict.

Astatine-211 alpha therapyOnly vendor: IONETIX
Somatostatin receptor PET (68Ga/64Cu-DOTATATE)Only vendor: Advanced Accelerator Applications (Novartis)

Longest chain6

The deepest dependency chain in the corpus, foundations first. Every step must hold for the last technology to be delivered.

  1. Medical cyclotrons, hot cells, and synthesis modules
  2. PET tracer manufacturing and distribution
  3. PET (positron emission tomography)
  4. PET/CT
  5. PSMA PET
  6. AI in nuclear medicine

Most relied upon8

Technologies with the most direct dependents. Improving one of these lifts everything to its right on the map.

Cyclotron isotope production (F-18, Ga-68, Cu-64, Zr-89, At-211)6 direct dependentsPET/CT6 direct dependentsMedical cyclotrons, hot cells, and synthesis modules4 direct dependentsRadiopharmacy and cyclotron networks4 direct dependentsTherapeutic isotope supply chain (Mo-99, Lu-177, Ac-225)4 direct dependentsAutomated synthesis modules2 direct dependentsCold kit formulation2 direct dependentsDOTA chelation2 direct dependents

Cycles to fix2

A dependency loop was recorded. The map drops one edge from each loop to draw it, but the data should be corrected in dependsOn.

  • Automated synthesis modules → Hot cells and radiation shielding → Automated synthesis modules
  • Cold kit formulation → Germanium-68/gallium-68 generators → Cold kit formulation

How the map is built

Layers and ordering

Each technology record can name the technologies it cannot be delivered without (dependsOn in src/data). A node sits one layer to the right of its deepest dependency (longest-path layering), and within a layer nodes are ordered by a few barycentre sweeps so arrows cross as little as possible.

Only true, uncontroversial requirements are recorded: manufacturing steps, instruments, software and upstream methods. “Often used with” is not a dependency; that lives in pairings and related links.

Hints and gaps

Chokepoints are articulation points of the map that something depends on; the longest chain is the deepest path; single-vendor steps count the companies linked to each technology in the corpus. Each is a prompt to look closer, not a judgement.

Missing a dependency? Add the id to the technology's dependsOn array, run npm run validate, and it appears here and on both technology pages. Every technology page also shows its own “Depends on” and “Needed by” strips. The wider graph explorer shows every other kind of link.