An optical endoscope able to achieve 9X zoom with no moving parts promises to significantly expand the usefulness of microendoscopy.1 Until now, optical endoscopy has been limited by fixed field of view (FOV) and resolution because miniaturization has dictated the incorporation of lensing that prohibits traditional zoom capability.
Researchers at Cornell University (Ithaca, NY) discovered that simply changing the wavelength of the excitation light allows switching between two modalities: one offering high-magnification, high-resolution, and small-FOV multiphoton fluorescence; and the other providing low-magnification, low-resolution, and large-FOV one-photon reflectance.
The device promises utility in clinical settings where large-FOV imaging is needed to identify a tissue area for study, and small-FOV and high-resolution imaging is useful immediately afterward for revealing cellular details in that area.
In imaging studies, the full-width half-maximum (FWHM) lateral resolution of the high-magnification mode measured approximately 0.8 µm with a 150 µm FOV, while the FWHM lateral resolution of the low-magnification mode was approximately 4.5 µm with a 1.3 mm FOV. The system's dual-modality capability was experimentally demonstrated using unstained ex-vivo mouse lung tissue with excellent imaging results.
1. D.G. Ouzounov et al., "Dual Modality Microendoscope with Optical Zoom Capability," CLEO 2012 conference, postdeadline paper ATh5A.2, San Jose, CA (May 2012).