According to one aspect, a planar and volumetric dosimeter for use with a radiotherapy machine having a radiation source. The dosimeter includes a scintillating assembly including a plurality of scintillating optical fibers and configured to generate a light output in response to incident dose distribution thereon from the radiation source, and a photo-detector operable to convert optical energy emitted by the scintillating assembly to electrical signals for determining actual two-dimensional (2D) or three-dimensional (3D) dose distribution incident on the scintillating assembly using a tomographic reconstruction algorithm.
