Instrumentation Available to Outside Users for ResearchPortable Raman Clinical Instrument
Raman clinical instrument is capable of collecting Raman spectra from biological tissues over the fingerprint range (400-1960 cm-1). The new Raman system will measure approximately 32” x 17” x 10” and sit on a low wheeled platform. The instrument uses an 830 nm diode laser, delivered through the probe, to excite Raman scattering. The probe delivers to and collects light with the probe tip in contact with tissue. Light from an 830 nm InGaAs diode laser (Process Instruments, Salt Lake City, UT) is passed through a holographic band pass filter centered at 830 nm (Kaiser Optical Systems Incorporated, Ann Arbor, MI). The light is then collimated and coupled into the 200 μm core diameter excitation fiber of the Raman probe. Illumination of the sample is gated by a high-speed, 6 mm aperture, computer-controlled shutter (LS6ZM2, Vincent Associates, Rochester, NY). The excitation fiber is terminated with an FC connector to provide day-to-day reproducibility of alignment. For 100 mW of excitation power, the resultant irradiance is 318 W/cm2 which has been clearly shown to not cause any tissue damage. The proximal end of the probe contains the collection fibers that are arranged in a vertical array and serve as the entrance slit to the spectrograph (Holospec f/1.8i, Kaiser Optical Systems), attached by means of a modified BNC connector. The collected Raman light is dispersed onto a back-illuminated, deep-depletion CCD detector with a 1024×256 array of pixels. The CCD detector is thermoelectrically cooled to -70oC. The probe is 4 m long and is 2 mm in overall diameter. Integrated software (LabVIEW and MATLAB) in the system enables rapid collection of Raman spectra (1s) and real-time analysis of the spectral parameters.
Multi-Modal Spectroscopy Instrument
The clinical MMS instrument and probe is used for in vivo and ex vivo studies to detect vulnerable plaques in arteries and also to diagnose breast cancer.
The Mini FastEEM is capable of collecting diffuse white light spectral reflectance and 340 nm-excited fluorescence.The DRS/IFS instrument uses two different light sources including a 337 nm N2 laser (NL100, Stanford Research Systems, Sunnyvale, CA) for fluorescence spectroscopy and a Xe lamp (L7684, Hamamatsu Corp., Bridgewater, NJ) for reflectance spectroscopy. The Xe lamp provides a 2.9 µs FWHM pulse of white light, 1 J/pulse max, given an external trigger supplied by the software. The N2 laser provides a 3.5 ns FWHM pulse of 337 nm light, 170 µJ per pulse. Light is delivered and collected from tissue via the FastEEM probe and is brought to the entrance slit of the diffraction grating spectrometer (Spectra Pro 150, Acton Research, Acton, MA). The collected light is dispersed onto an intensified CCD detector (PIMAX, Roper Scientific, Princeton, NJ). To insure easy reproducibility, the collection fibers have individual SMA adapters that connect to the spectrograph. The CCD is operated in a gated mode and is thermoelectrically cooled to 20C. The total collection time for fluorescence and reflectance spectra is approximately 0.3 s. Several of these acquisitions can be averaged together to increase the SNR, making a typical acquisition time on the order of 1.5 s. Integrated software (LabVIEW and Matlab) in the system enables rapid collection of DRS and IFS spectra.
Transdermal Glucose Detection Raman System
The portable instrument it is modeled after the laboratory system but several design changes make it more compact and versatile. For light delivery and collection, we have converted free-space optics into an optical fiber based system. In addition, a tunable wavelength spectrograph and a thermoelectrically-cooled CCD (Princeton Instruments) are used for spectra collection. We have also developed non-imaging optical elements to improve the performance of the instrument. The unit is a portable system transported to hospitals for clinical investigations.
Portable NIR Raman Clinical Instrument for Glucose Detection
- 830 nm diode laser (Process Instrument, PI-ECL-830-500-FS, 500mw)
- Deep depletion CCD (Princeton Instruments, Spec10 XTE)
- LS-785 Spectrograph (Princeton Instruments)
- Raman edge filters, fiber optic assembly and non-imaging optics for light collection,
- Raman microprobe.
Optical Spectroscopic Scanner for Comprehensive Assessment of Surgical Excision Margins Project
Fast and reliable intra-operative diagnosis is a critical component of successful oncological surgery in a variety of organ systems. While optical probe and in vivo imaging strategies have been proposed by us and others as potential tools for surgical margin assessment, there continues to exist a significant clinical need for rapid and reliable evaluation of excised tissues in real time. In this work, however, we are developing a new and complementary strategy to enable real-time comprehensive assessment of surgical margins in excised tissues. While in vivo imaging remains a highly desirable research ideal, short-term clinical benefits are much more likely to result from ex vivo systems that are capable of imaging excised tissues at high resolution, free of motion artifacts, blood and other clinical constraints commonly imposed on operative tools that come in contact with the patient. Specifically, the instrument is a wide-area spectroscopic scanner, capable of multi-modal quantitative spectroscopy at high resolution. As such, large surgical margins, such as the entire surface of an excised breast lesion, can be quantitatively assessed in real-time.
- 2-D mechanical scanning (M-605.1DD and M-126.DG1, Physik Instrument)
- Xenon arch lamp (oriel) 500W
- White light LED source (CCD PSB-1012V-WW)
- XY High speed steering mirror
- Spectrograph (Acton Standard Series SP-2150i)
- CCD Camera (Photon Max 512)
- Miniature xenon arc lamp 55W
- Pulsed diode pumped solid state laser (SNV-40F-000, Teem Photonics).
- Dual axes translation stage : Advance tech – max travel distance ~ 10 inch x 10 inch
- Spectrometer (USB 2000+, Ocean Optics)