In the 1970s, the basis for the positron imaging in Finland was established in Turku when the first cyclotron was installed. As the cyclotron practically was a prototype, the initial efforts aimed to develop targets for isotope production. The first tracers produced were 11-C labeled ethanol. Soon after an 81-Rb/81m-Kr generator for lung perfusion studies in patients was developed. In collaboration with the University of Wisconsin high pressure targetry systems for fluorine chemistry were installed, thus increasing the yield and allowing Turku to produce 18-FDG as one of the first laboratories in Europe. To construct a method suitable for the routine use of high specific activity [18F]F2 for synthesis of tracers for PET, a special excitation method via an electric discharge through the gas was developed leading to a specific activity of up to 55 GBq/umol. These above mentioned inventions have had a significant impact on further development in cyclotron targetry and radiochemistry.
At the start in the seventies, the cyclotron-PET international community was small. The core of the society was gathered together in Turku in 1977 to draw guidelines how cyclotrons ought to be used in medicine. Since then every third year a “Medical Application of Cyclotrons” symposium, more recently known as Turku PET Symposium has been held in Turku, thus serving bi-directional communication.
As in the seventies the main emphasis was focused on the cyclotron laboratory and targetry, the eighties provided the breakthrough of radiochemistry in Turku. The gas pipeline from cyclotron to the hospital was built. At the University hospital a special high energy collimator equipped gamma camera was used to perform studies on brain and thyroid tumor patients in 1981 (also with coincidence capabilities). Number of different tracers were used in the studies in animals and humans.
In 1988 the first genuine whole body PET scanner (ECAT CTI-931) was purchased. After rapid development in radiochemistry in the eighties, the scientific PET efforts were established in the nineties. The research activities in the PET unit increased very fast and the scientific productivity was boosted rapidly. As the PET facilities were situated inside a university teaching hospital, scientific groups were encouraged to work on clinical problems like degenerative neurological disorders, cancer, diabetes, coronary heart disease, psychiatric disorders, foetal asphyxia and certain rare inherited diseases typical for our country.
Thanks to skilled physicists and radiochemists, a great variety of 11-C and 18-F labeled radiotracers were available at the PET centre in Turku. In addition to the accelerator at Åbo Akademi used for 11-C and 18-F production, a small cyclotron for 15-O production was installed in 1992 (CYCLONE 3, Ion Beam Application, Belgium). The second PET scanner was installed (GE Advance) in 1996 further increasing the imaging capacity of the Centre.
In 1996 the Turku PET Centre established a national status from the Ministry of Education. Together with the increased budget funding and rapidly enhanced research activities and research contracts with industry, the resources for hiring more staff and to attach clinical investigators were strikingly increased. Close collaboration had been established with laboratories in Uppsala, Stockholm, Copenhagen, London, Orsay, Dresden, St. Petersburg, Brookhaven, Michigan, Tohoku and Akita. In 2002 collaboration with industry was expanded and long term contracts were signed.
The two first medical doctoral theses in this field in Turku were published from the conventional Nuclear Medicine in 1980. Thereafter, the research activities in Turku have been mainly concentrated on positron studies although in many of the projects both positron and conventional nuclear medicine imaging as well as ultrasound, magnetic resonance imaging and x-ray computed tomography techniques have been applied. The number of doctoral theses produced from the PET Centre is nearly 100 and the number of scientific papers is over about 1000, mostly in high quality peer-reviewed journals (more complete list of publications at: Publications).