isotopes

A short-lived radioactive form of fluorine, made fresh each morning at a local facility, that is attached to a sugar or other small molecule and used for a PET scan.

A radioactive metal with a one-hour lifetime that is eluted from a shielded generator or made on a cyclotron and attached to a molecule that finds tumours, giving a PET scan the same day.

A radioactive metal that gives off short-range radiation. Attached to a molecule that sticks to a tumour, it irradiates the tumour from the inside while sparing most healthy tissue.

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.

A radioactive form of iodine. Because the thyroid gland naturally absorbs iodine, swallowing it lets the radiation destroy thyroid cells or thyroid cancer cells almost anywhere they have spread, with very little effect on the rest of the body.

A radioactive metal that fires high-energy particles a short distance into surrounding tissue. Millions of microscopic beads carrying it are injected into the artery feeding a liver tumour, where they lodge and irradiate the tumour from inside.

A metal that fires off very powerful, very short-range radioactive particles as it decays through a chain of daughter atoms. Because the particles barely travel beyond the cell they hit, it can kill a cancer cell while leaving neighbouring healthy cells mostly untouched. Supply is scarce, so it is still mostly used in research studies.

A radioactive metal that lasts about half a day, long enough to image slower-moving molecules such as antibodies, and chemically identical to copper-67, the isotope used to treat with the same tracer.

A radioactive form of iodine that decays quickly and gives off gamma rays, used to take a picture of the thyroid or, attached to a nerve-tracing molecule, of tumours of the adrenal gland and nervous system, before deciding whether a therapeutic dose of iodine-131 makes sense.

A radioactive metal used, attached to octreotide, as the original scan for neuroendocrine tumours (Octreoscan) before gallium-68 PET took over, and still used to label white blood cells for infection imaging.

A radioactive metal that, once inside the body, turns itself into a much more damaging particle-emitter over the following hours. It is being explored as a way to deliver strong, short-range radiation without needing the rarer isotopes used in similar treatments.

A radioactive gas-forming isotope with a ten-minute lifetime, turned into ammonia and injected to map blood flow to the heart muscle on a PET scan.

A radioactive form of the mineral radium that behaves like calcium and settles into bone. It gives off very short-range, high-energy particles that damage cancer growing in bone while barely reaching the healthy marrow next to it.

A radioactive potassium look-alike that lasts only about 75 seconds, delivered straight from a bedside generator into a vein, used to check blood flow to the heart without needing a cyclotron on site.

A radioactive gas that a patient simply breathes in and out while the camera runs. It decays in thirteen seconds, so the picture is of ventilation happening now rather than of particles left behind, and it has to be generated in the room from a parent that itself lasts only a few hours.

A radioactive metal, given as an injection, that homes in on the actively growing edges of bone and gives off radiation there. It is used to ease pain from cancer that has spread to bone.

A radioactive metal that behaves like calcium and is taken up by bone, particularly where cancer has spread there. A single injection can ease bone pain for weeks by irradiating those spots from within.

A radioactive potassium look-alike with a three-day lifetime, injected to see how well blood reaches, and heart muscle survives in, different parts of the heart on a SPECT scan.

A radioactive form of ordinary carbon that lasts only about 20 minutes, so it has to be made and used in the same building; it can label real body molecules like choline without changing their chemistry.

A radioactive form of copper that pairs with a diagnostic twin made of the same element, copper-64. Using the same metal for the scan and the treatment means the tracer behaves identically both times, which should make dosing more predictable.

An older radioactive gallium tracer, given as a citrate injection, that lights up infections and some tumours over a scan taken a few days later; mostly replaced now by FDG PET but still used where PET is unavailable.

The long-lived parent locked inside a gallium-68 generator. One loaded column can supply a year's worth of PET tracer doses for prostate cancer and neuroendocrine tumour scans, but the generators themselves have been expensive and slow to get.

A radioactive metal built into tiny beads that are injected into the artery feeding a liver tumour, where they lodge and irradiate it from close range. Unlike similar beads made with yttrium-90, these can also be seen clearly on a scan.

A radioactive form of oxygen with a two-minute lifetime, made into water and injected to measure blood flow to the brain or heart; used almost exclusively in research because it decays too fast for routine hospital use in the US.

A radioactive form of phosphorus, one of the oldest radioactive treatments in medicine. Because the body's cells constantly use phosphorus, it can be used to treat certain blood disorders or, injected directly into a body cavity, to control fluid build-up caused by cancer.

A high-energy radioactive metal that a hospital can produce on demand from a small on-site generator, similar to how a common medical imaging isotope is made, rather than needing to import it. It is used for hard-to-reach tumours, including liver cancer.

A radioactive metal that lasts about three days, long enough to attach to a whole antibody and follow it around the body for several days on a PET scan, which is why it underpins 'immuno-PET'.

A radioactive halogen, chemically similar to iodine, that gives off a single powerful short-range particle as it decays. It has to be made in a particular kind of accelerator and used within hours, which is why only a handful of centres worldwide can supply it.

An extremely short-lived radioactive metal that delivers a powerful, very local burst of radiation. Because it decays away within a few hours, it has to be made freshly at the hospital, right before it is given to the patient.

A long-lived, PET-visible form of radioactive iodine used to map how a thyroid cancer takes up iodine over several days, so the dose of the treatment isotope, iodine-131, can be planned before it is given.

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.

A radioactive form of radium used mainly as a feedstock: it is loaded into a small on-site generator so that hospitals and manufacturers can draw off a different, more widely used radioactive metal (lead-212) whenever they need it.

An experimental radioactive metal, lasting about four hours, being developed as a PET-imageable stand-in for lutetium-177 or other therapy metals so a treatment dose can be planned in advance.

A radioactive metal being developed to pair with imaging twins made of the same element, scandium-43 or scandium-44. Because it is the same chemical element used for both the scan and the treatment, the tracer should behave identically in both roles.

A radioactive metal, chemically almost identical to the widely-used lutetium-177, that gives off the same kind of medium-range particles plus a burst of extra very-short-range electrons. Those extra electrons may let it do more damage to a cancer cell than lutetium-177 while using the same delivery molecules.

A radioactive metal that, once it decays, keeps generating more damaging radioactive particles inside the tumour for weeks. Because it lasts longer than most similar treatments, it can be attached to slow-moving carriers such as full-sized antibodies.

A PET-visible radioactive stand-in for the treatment isotope yttrium-90, used to see in advance, on a scan, exactly where a yttrium-90 therapy dose would go and how much radiation each organ would receive.