X-ray phase-contrast tomography based on synchrotron radiation sources

The experiments were carried out at the ANKA synchrotron radiation facility, Institute for Synchrotron Radiation (ISS), Forschungszentrum Karlsruhe, Germany, in collaboration with the Entomology Unit (IAEA Laboratories), the Atominstitut (Vienna) and the ANKA synchrotron facility Tomo-Topo beamline team. The purpose was to perform X-ray phase-contrast tomography of malaria transmitting mosquitoes (genus Anopheles) selected from irradiated and control groups as well as radiographic imaging of living and chemically fixed Tsetse flies (Glossina pallidipes). The X-ray phase-contrast imaging technique allows radiographic-like imaging of samples characterized by very weak or no absorption contrast. This technique is of special interest for radiography of soft tissue, small animals, and insects where the available material is not sufficient to produce satisfactory absorption contrast. Another advantage of the technique over the X-ray absorption radiography is minimization of the radiation dose to the sample. The technique enables the investigation of living animals or the performance of tomographic imaging with longer exposition time with minimum radiation damage to the otherwise sensitive and delicate samples. Images of the malaria transmitting mosquitoes can provide information about morphological differences between the irradiated and control groups of specimens. It is of prime importance for a successful application of the sterile insect technique (SIT) that the irradiated (sterile) group of male mosquitoes is healthy and can compete with the local population of males during mating. In the case of Tsetse flies there is also an interest in in vivo investigation of the mating process as well as in learning more about the morphology of specific organs, such as salivary glands and reproductive organs. The experiments confirmed a possibility to perform imaging of the morphological details for live species of mosquito and flies as well as to study in vivo processes by using X-ray phase contrast technique based on synchrotron radiation sources. Data for CT imaging of mosquito species require further examination by specialists from the Entomology Unit. There is also a need to modify or develop new sample fixing procedures which would improve X-ray phase contrast for specific organs and structures inside the mosquito body