Spectrally encoded confocal microscopy of esophageal tissues at 100 kHz line rate

Abstract

Spectrally encoded confocal microscopy (SECM) is a reflectance confocal microscopy technology that uses a diffraction grating to illuminate different locations on the sample with distinct wavelengths. SECM can obtain line images without any beam scanning devices, which opens up the possibility of high-speed imaging with relatively simple probe optics. This feature makes SECM a promising technology for rapid endoscopic imaging of internal organs, such as the esophagus, at microscopic resolution. SECM imaging of the esophagus has been previously demonstrated at relatively low line rates (5 kHz). In this paper, we demonstrate SECM imaging of large regions of esophageal tissues at a high line imaging rate of 100 kHz. The SECM system comprises a wavelength-swept source with a fast sweep rate (100 kHz), high output power (80 mW), and a detector unit with a large bandwidth (100 MHz). The sensitivity of the 100-kHz SECM system was measured to be 60 dB and the transverse resolution was 1.6 µm. Excised swine and human esophageal tissues were imaged with the 100-kHz SECM system at a rate of 6.6 mm 2 /sec. Architectural and cellular features of esophageal tissues could be clearly visualized in the SECM images, including papillae, glands, and nuclei. These results demonstrate that largearea SECM imaging of esophageal tissues can be successfully conducted at a high line imaging rate of 100 kHz, which will enable whole-organ SECM imaging in vivo.

Spectrally encoded confocal microscopy for diagnosing breast cancer in excision and margin specimens

“…19,20 Study results also show that intra- and inter-observer agreements for SECM are high. With the high diagnostic accuracy demonstrated in this paper and fast imaging speed shown in our previous work 24 , SECM will uniquely enable microscopic imaging of the entire breast excision specimens in a short imaging time and provide accurate margin status during the surgery. Real-time feedback regarding the margin status will be used to conduct additional re-resections to finally achieve negative margin during the initial surgery, which can obviate the need for additional surgeries.…”

“…Utilizing a high-speed wavelength-swept source (repetition rate = 100 kHz) and a fast detector unit, SECM was previously demonstrated to rapidly image a human esophageal tissue over an area of 1 cm 2 in 15 seconds. 24 When used during breast cancer surgery, the high speed of SECM could enable the surface of an entire surgical specimen to be rapidly imaged. SECM images can then be used to visually evaluate the margin status.…”

All-fiber wavelength swept ring laser based on Fabry-Perot filter for optical frequency domain imaging

“…The final output repetition rate can be increased over that of the master oscillator and filter by reducing the duty cycle of the oscillator and using an interleaver, such as a Mach-Zehnder type [15] or parallel-split delay line [17,18]. The interleaver design used in this work, Fig.…”

Speed-dependent resolution analysis of ultrafast laser-scanning fluorescence microscopy

“…For example, an AOD with a 100 kHz scan rate (v ∼ 0.1) has been employed for nonfluorescent imaging [30]. In addition, the swept-source originally developed for optical coherence tomography (OCT) and spectrallyencoded imaging in a longer near-infrared (NIR) range (∼800-1500 nm), can now achieve a swept-rate of >100 kHz [31][32][33][34]. If this swept-source can be realized in the visible range, a spectral-encoded laser-scanning solution at multihundreds kHz could also be a viable solution to scale up the speed of LSFM to the limit.…”