| Zusammenfassung |
The PTB accelerator facility (PIAF) for ion and neutron research and the charged particle microbeam are established user facilities which have been used for a variety of international projects and European framework programmes. The microbeam facility has been in routine operation for more than 15 years and irradiations of various cell types have been carried out for a variety of collaborative projects with outside groups. In particular, the PTB-microbeam has been part of the INTERSTANDER project for the investigation of bystander effects and the BioQuaRT project.
The microbeam provides high-LET α-particles and low-LET protons with energies of (2 to 20) MeV. This range of ions and energies allows the selection of radiation qualities with LET values between (3 to 200) keV/μm, which covers almost entirely the range from diagnostic X-rays to naturally occurring α-radiation. With the charged-particle microbeam, substructures (cell nucleus or cytoplasm) of individual cells can be targeted with a spatial resolution of about 2 μm and irradiated with a single particle or with precisely counted multiple particles.
For the study of bystander effects, it is possible either to target selected cells or a fraction of cells in a dish and study the radiation response in directly irradiated and bystander cells. Presently, up to 50,000 cells per hour can be automatically processed including all experimental steps (imaging, cell recognition, position analysis and irradiation). The use of reference markers allows revisiting of each cell in a dish for later analysis of radiation response using a variety of endpoints. Live-cell imaging of GFP- or RFP-tagged reporter genes has been established at PTB and is available.
In addition to microbeam irradiations, broadbeam irradiations with protons or α- particles and irradiations in neutron fields with energies in the range (0.1 to 15) MeV can also be made available.
An S1 laboratory for cell culture and microbiological preparations is available in close proximity to the microbeam facility. The local research team will carry out all the procedures at the microbeam and will support the external partners as much as possible. Access to the biology laboratory well ahead of the scheduled microbeam time can be provided for initial preparations and developments, studies of backgrounds (γ-H2AX, etc) and controls, as well as tests using an α-source. There is a guest house on site and a hotel located close to PTB.
In summary, the experimental conditions are perfectly suited to external research groups studying in detail biological effects at the level of individual cells (or co-cultures) and tissues with single particles, low doses or inhomogeneous dose distributions. |
