Isotropic resolution

Isotropic resolution

The lateral resolution of SPIM is comparable to that of a standard (epi) fluorescence microscope, as it is determined fully by the detection objective and the wavelength of the detected light. E.g. for detection in the green spectral region around 525 nm, a resolution of 250–500 nm can be reached. The axial resolution is worse than the lateral (about a factor of 4), but it can be improved by using a thinner lightsheet, like in the case of the QLS-scope, in which case nearly isotropic resolution is possible. Real isotropic resolution can be achieved by computationally combining 3D image stacks taken from the same sample under different angles. Then the depth-resolution information lacking in one stack is supplied from another stack; for example with two orthogonal stacks the (poor-resolution) axial direction in one stack is a (high-resolution) lateral direction in the other stack. The QLS-scope can perform measurements in different angles and recombine them to create a 3D image with real isotropic resolution like the example we present below: