Calculations of responses for experimentally studied silicon planar structures (epitaxial single-strip silicon diodes) have been carried out for various profiles of microbeams. The spatial distribution of responses on the microbeam radiation therapy (MRT) beams has been calculated taken into account both electrical field distribution inside of the detector and recombination in the diffusion region. Contributions to the responses from the space charge region (SCR) and the diffusion region are compared. It has been shown that the spatial resolution and the detector efficiency in edge on mode of the detector relative to X-ray microbeam can be higher than for the face on irradiation geometry. The response functions of diodes under MRT irradiation for a simple physical model have been obtained analytically. That allows calculating responses using the convolution procedure for different beam profiles. © 2013 IEEE.