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Microbeam Radiation Therapy Applied to Brain Tumour Model in Rats

last modified 13-09-2007 14:06

Microbeam radiation therapy (MRT) involves irradiation with arrays of microbeams issued from synchrotron radiation X-rays. A filtered white beam with typically 25 µm wide microbeams and 100 or 200 µm centre-to-centre spacing is used.


A significant proportion of the normal brain tissue is spared when the doses of radiation deposited by the microbeams is in the order of thousands of grays (Figure 1) [1,2].

Figure 1: Photo of a stained horizontal brain tissue section after the passage of micro beams, showing the destruction of cells in the path of the beams while other tissues remain intact (image from: Laissue et al.).

The purpose of our work was to develop this technique at the ESRF by (i) repeating the experiment performed by Laissue et al. [3]; (ii) optimising the experimental parameters, and (iii) comparing the technique with other synchrotron-based therapy techniques. Survival curves obtained after irradiation are plotted in Figure 2.

Figure 2: Survival curves obtained after irradiation. Details of the series are presented in Table 1, below.

Series Cells type Protocol of implantation Spacing Rats per series
1 9L 104 c in 1 µl 200 µm 23
2 9L 104 c in 1 µl 200 µm 11
3 9L 104 c in 1 µl 100 µm 12
7(seam) 9L 104 c in 1 µl no spacing 12
Ctrl 9L 104 c in 1 µl no irradiation 6

Table 1: The irradiation protocol.

Although the survival time obtained in this experiment is smaller than the one obtained by Laissue [4], there is the same proportion of rats showing a complete ablation of the tumour after irradiation. Future experiments will be devoted to finding the best compromise between tumour destruction and preservation of normal brain tissue in order to improve the survival curves.

Authors
P. Regnard, G. Le Duc, E. Brauer, I. Troprès, L. Lamalle, S. Bouvier, C. Clair, H. Bernard, A. Joubert, F. Lopes, J. Gastaldo, D. Dallery, J. Laissue and A. Bravin.

References
[1] Zeman, Curtis et al. 1961.
[2] Curtis 1967.
[3] Laissue et al., 1998.
[4] Laissue, Geiser et al. 1998.

Further Information

 

European Synchrotron Radiation Facility