Since the 1940s doctors have been using radioisotopes of iodine to see whether a patient's thyroid gland is working and to treat cancers in that organ. This exploits a natural process where the thyroid takes iodine, radioactive or otherwise, from the blood and uses it to make hormones.

Cancers occurring elsewhere in the body can be harder to pin down.

"Now we're identifying molecules that go to a specific tumour, or target a specific function in a given cell," said Professor Nabil Morcos, Research Leader with ANSTO Radiopharmaceuticals. These could be antibodies designed to bind to a cancerous cell, or a compound that sticks to dying cells.

"We might want to know if a tumour has grown or shrunk, or, after a heart attack, to see which part of the heart tissue is dead or dying," Nabil explained.

Couple these homing agents with the right kind of radioisotope and you've got yourself a handy tool for seeing inside the body.

Another of the many projects Nabil has on the go is developing a target for the most dangerous form of skin cancer, melanoma.

The idea is to give a melanin-seeking agent a radioactive label. Although melanin (the pigment that colours our skin, hair and eyes) is in every skin cell, it gets concentrated in melanomas. "Tumours would show up as a hot spot," Nabil said.

As exciting as these new diagnostic tools are, Nabil says therapy is really where it's at.

One of the most common radioisotopes used to treat cancers is yttrium-90. The beta particles it releases are perfect for killing off cancerous cells because they don't travel very far, so they aren't likely to knock off healthy tissue. But this also makes it impossible to tell exactly where its gone.

"You need the type of radiation that goes through the body so you can take a picture of it," Nabil said. Which means x-rays or gamma rays.

"One of the newest and most exciting things for the medical community is lutetium-177 because it releases one huge wallop of a beta-ray right into the tumour, and it has a gamma component so I can see where it goes," he said.

"Also, because it's taken up by the tumour, I can use it to see if the tumour is still growing -- I don't need to give a therapeutic dose, just enough for imaging," he added.

Of course, all this requires a regular supply of the radioisotope.

Naturally occurring lutetium comes in two types: 97 per cent is lutetium-175, the rest is lutetium-176. "If we put naturally occurring lutetium in the reactor, only a small fraction is going to become lutetium-177," Nabil said.

"We at ANSTO are one of, if not the only, place in the world that can make every atom lutetium-177."

"We do this by taking the element below lutetium on the periodic table, ytterbium-176. We put it in the reactor and make ytterbium-177 which decays, losing a proton and gaining a neutron, to become lutetium-177," he explained.

Clinical trials of what Nabil refers to as "sexy" lutetium-177 get under way at hospitals in Brisbane and Perth this September.

Scientists Paula Berghofer and Dr Vu Nguyen are members of ANSTO's pharmacology team. They are pictured here with a gamma camera used for animal imaging. Their roles are to study the effects of radiopharmaceuticals on human cells and animal systems and to provide support to collaborators from industry and universities.