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Mouse Ear Irradiation Model

We have developed equipment, techniques and protocols that allow us to irradiate a mouse ear using the charged-particle microbeam.  Shown here is a custom designed holder to position the flattened mouse ear over the microbeam port

The ear of a mouse, measuring approximately 13 mm in both length and width and with an average thickness of 250 µm, can be used for radiation-induced  bystander studies in vivo with our 3-MeV proton microbeam, which has a range of 134 µm. It is possible to irradiate a small area of the mouse ear and investigate bystander effects in non-targeted regions.

- For microbeam experiments, cells along a 6 mm line of a C57BL/6 mouse ear are irradiated with 3 MeV proton beam (~12.5 keV/µm, range 134 µm) with a diameter of ~ 35 µm

- Sham-irradiated animal served as controls

- 30 min after irradiation tissues were fixed, embedded and cut for analysis of radiation-induced biological endpoints such as the formation of radiation-induced DNA repair protein foci

- We found that compared to control, proton irradiation induces gammaH2AX foci formation. Strikingly, although the proton beam size was of ~ 35 µm in diameter the average length spanned by gammaH2AX positive cells was >150 µm.

- It can be speculated that microbeam proton irradiation induced DNA damage also in non-irradiated bystander cells that were in proximity to directly irradiated cells

If you are looking to do animal irradiations at RARAF, contact the RARAF staff before planning as any irradiation/handling protocols will be required to submit a research plan for approval to the Columbia University Institutional Animal Care and Use Committee (IACUC)


tel: (914) 591-9244
fax: (914) 591-9405
Radiological Research Accelerator Facility Nevis Laboratories
P.O. Box 21, 136 S. Broadway, Irvington, N.Y. 10533