# Endoscopic Optical Imaging Technologies and Devices for Medical Purposes: State of the Art
## 8 Conclusions  
In the present paper, we reviewed the different imaging techniques used in medical applications. The continuous growth of microfabrication techniques and optical components make the latest imaging devices much smaller, allowing visualization of narrower sections of the body and imaging of target areas with a very fine resolution. The thinner the imaging device is, the further the imaging device can be advanced into the body, which enables improved detection of the lesion/tumor surface.  
In medical applications, OCT is a frequently used imaging modality to image tissue structures due to the smaller size of the probe device; among this type, FD-OCT is widely used. Among the other imaging modalities, nonlinear microscopy can generate images with a finer resolution, while photoacoustic imaging can image deeper into the tissue. A large number of imaging probes have been developed using electrostatic actuation due to the ease of fabrication and fast scanning speed.  
In conclusion, the advancement of MEMSs and small-sized optical components enable the fabrication of imaging devices with promising performance as compared to the traditional medical devices. Such devices enable the detection of lesions/tumors at an earlier stage and act as a guide during surgical procedures, increasing diagnostic capabilities.  
Conceptualization, C.M. and M.K.; formal analysis, M.K.; investigation, M.K.; resources, M.K.; data curation, M.K.; writing--original draft preparation, M.K.; writing--review and editing, M.K., P.M.L., and C.M.; visualization, M.K.; supervision, C.M., and P.M.L.; project administration, C.M., and P.M.L.; funding acquisition, C.M., and P.M.L. All authors have read and agreed to the published version of the manuscript.  
\begin{table}
\begin{tabular}{l l l l l l l l} \hline \hline  & \begin{tabular}{c} **Working** \\ **Principle** \\ \end{tabular} & **Frequency** & **FOV** & **Drive Voltage** & **Scanner Dimensions** & \begin{tabular}{c} **Scanning** \\ **Pattern** \\ \end{tabular} & **References** \\ \hline OmrVision camera & Chip on tip camera & - & \begin{tabular}{c} 364 μm \(\times\) \\ 364 μm \\ 160 μm \(\times\) \\ 400 μm \(\times\) \\ 280 μm \\ 280 μm \\ 280 μm \\ 280 μm \\ 280 μm \\ \end{tabular} & 3.3 Vac & \begin{tabular}{c} 650 μm \(\times\) 650 μm \(\times\) \\ 1158 μm \\ 350 μm \(\times\) 18 mm \\ 350 μm \(\times\) 18 mm \\ 400 μm \(\times\) \\ 280 μm \\ \end{tabular} & - & [142] \\ Scanning confocal microscope & Electrostatic confocal microscopy & \begin{tabular}{c} 4 kHz \\ 100 μm \\ (low scan) \\ 100 μm \\ (low scan) \\ 100 μm \\ 280 μm \\ \end{tabular} & - & \
\begin{tabular}{c} 350 μm \(\times\) 18 mm \\ diameter 20 mm Rigid \\ 280 μm \\ 100 μm \\ 200 μm \\ 12 mm \(\times\) 25 mm \(\times\) 6.5 \\ mm \\ 295 μm \\ 100 μm \\ \end{tabular} & - & [23] \\ Scanning confocal microscope &
\begin{tabular}{c} 120 μm \\ 120 μm \\ (in diameter) \\ 295 μm \\ 100 μm \\ 200 μm \\ 2.0 mm \(\times\) 1.9 mm \\ 2.4 mm (in diameter) \\ 2.  
**Funding:** This work was supported by the Natural Sciences and Engineering Research Council (NSERC) of Canada, Canadian Institutes of Health Research (CIHR), the Canada Research Chair (CRC) program, and the Mitacs internship program.  
**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.