FAQs
Is it a light sheet microscope?
Yes and no. It is based on light-sheet measurements, but the use of statistics from several angles includes an extra step in the process.
Is it an OPT system?
Yes and no. It is based on the same principles as OPT to reconstruct a 3D volume (based on the inverse radon transform, for example) but the image is generated based on LSM principles.
How does QLS-scope compare to Multiview SPIM?
QLS-scope measures hundreds of angles to obtain an image, not just two or four opposing measurements as Mview SPIM. Qscope does not require the use of beads to help the 3D reconstruction, it automatically finds the center of rotation. Mview SPIM obtains measurements at different angles simultaneously, Qscope obtains these sequentially.
Can I use any clearing solution with QLS-scope?
Yes. Samples with their clearing solution are inserted in a test-tube, which is then immersed in an index-matching fluid. As long as the clearing solution is transparent, it may be used in the QLS-scope.
I need to image something larger than 1cm. Is this possible?
Yes, it is possible, but note that the larger the sample the harder it becomes to render it transparent. In these cases, what fails is not the imaging technology, but the clearing method. It is recommended to slice these tissues into 1cm sections which can be long (up to 5cm), but not more than 1cm in diameter. The QLS-scope may be adapted to image larger samples if proven to be transparent (at an extra cost, since this requires extra optics).
What about photobleaching? Doesn´t increasing the number of angles increase the light exposure?
True, it does. However, by reducing the time it requires for each SPIM stack (z-stack) we have more time available for angular measurements. If photobleaching is an issue, reduced number of angles may be obtained, in which case more advanced reconstruction methods (also provided) are required, albeit with a small reduction in resolution.
Generation of isotropic voxels implies using hundreds of angular measurements, thus an increase of light exposure.
Since each angular measurement (i.e. each full SPIM stack) takes 0.1-2 seconds, the overall exposure time is less than current SPIM systems. Lower number of angles may be used to increase speed and thus image in 3D dynamic processes at more than 200fps (at approx. 10 volumes/second).
What does the QLS in QLS-scope stand for?
QLS stands for Quantitative Light Sheet. The QLS-scope registers the intensity of the lasers and the exposure time during each acquisition, thus presenting quantitative data independent on laser power and camera exposure. Identical samples will generate equivalent quantitative values even when measured at different conditions.