A year ago this month, Steve Jobs, the chief executive of Apple, died from neuroendocrine cancer. There is no doubt he was a remarkable man who managed to pull the once-ailing company back from the abyss and turn it into the behemoth it is today.
He was first diagnosed with cancer in 2004, and tried a variety of treatments, some conventional, some not, to cure the disease.
Recently it was revealed Jobs spent time at the University of Basel in Switzerland in 2009.
Although the details are sketchy, it is widely believed he was undergoing peptide receptor radionuclide therapy (PRRT), a new treatment unavailable in the United States (or in New Zealand, for that matter), which involves "tagging" a biological molecule with a radioactive nucleus.
The body recognises the biological molecule, and is therefore fooled into delivering it and its radioactive payload to a tumour, which should then be killed by the intense radiation.
The radioactive nuclei used in PRRT are isotopes of the chemical elements yttrium (Y) and lutetium (Lu).
As these are not exactly household names, let's learn a little about both.
Yttrium (pronounced 'it-ree-um') is a metal, first isolated in pure form in 1828. Its name comes from the town of Ytterby in Sweden, which is unique in having four chemical elements (Yttrium) (Y), Ytterbium (Yb), Terbium (Tb) and Erbium (Er) named after it - each of these elements was originally obtained from mineral deposits near the town. Yttrium is used in various alloys to improve properties such as weight and workability, in glass to make it resistant to shock and heat, and also in lasers.
Yttrium was also used in the red phosphors of older-style colour TVs. However, much of the recent interest in yttrium has centred on the 1987 discovery of a material containing this, along with copper, barium and oxygen, which was found to be a superconductor at liquid nitrogen temperature (-196edgC). This was a very big deal, as wires made of such materials can potentially conduct electricity with no losses, and require only cooling with relatively inexpensive liquid nitrogen.
Kiwi scientist Jeff Tallon, at Industrial Research Limited in Wellington, has been instrumental in bringing a superconducting wire of this type (although not containing yttrium) to market.
Lutetium (pronounced 'loo-tee-shee-um') is also a metal, but of much more recent vintage than yttrium. While a compound of lutetium was first discovered in 1907, the pure metal was not prepared until 1953. The name of the element is derived from Lutetia, the Latin name for Paris, as the 1907 discovery was made there.
Surprisingly, (and I will confess to not knowing this until I started reading up on this subject) lutetium was at one time the most expensive naturally-occurring metal in the periodic table, although at $US2200 ($NZ2700) a kilogram, it is now much cheaper than gold (US$57,000 per kilogram). However, this price still precludes wide use.
So while neither yttrium nor lutetium has a significant number of commercial applications, their radioactive isotopes 90Y and 177Lu are useful in PRRT as they emit radiation of sufficient energy and range to kill tumours, while having short enough half-lives to ensure that the radiation dose will not be damaging to other organs in the body.
We'll never know if PRRT made a difference to Steve Jobs' cancer.
But it's vital that new and more effective treatments continue to be developed in the fight against this insidious affliction.
Dr Blackman is an associate professor in the chemistry department at the University of Otago.
