Small Portable Interchangeable Imager of Fluorescence for Fluorescence Guided Surgery and Research

Abstract

Fluorescence guided surgery (FGS) is a developing field of surgical and oncologic research. Practically, FGS has shown useful applications in urologic surgery, benign biliary surgery, colorectal cancer liver metastasis resection, and ovarian cancer debulking. Most notably in in cancer surgery, FGS allows for the clear delineation of cancerous tissue from benign tissue. FGS requires the utilization of a fluorescent contrast agent and an intraoperative fluorescence imaging device (IFID). Currently available IFIDs are expensive, unable to work with multiple fluorophores, and can be cumbersome. This study aims to describe the development and utility of a small, cost-efficient, and interchangeable IFID made from commercially available components. Extensive research was done to design and construct a light-weight, portable, and cost-effective IFID. We researched the capabilities, size, and cost of several camera types and eventually decided on a near-infrared (NIR) charged couple device (CCD) camera for its overall profile. The small portable interchangeable imager of fluorescence (SPIIF) is a “scout” IFID system for FGS. The main components of the SPIIF are a NIR CCD camera with an articulating light filter. These components and a LED light source with an attached heat sink are mounted on a small metal platform. The system is connected to a laptop by a USB 2.0 cable. Pixielink © software on the laptop runs the system by controlling exposure time, gain, and image capture. After developing the system, we evaluated its utility as an IFID. The system weighs less than two pounds and can cover a large area. Due to its small size, it is easily made sterile by covering it with any sterile plastic sheet. To determine the system’s ability to detect fluorescent signal, we used the SPIIF to detect indocyanine green under ex and in-vivo conditions and fluorescein under ex-vivo conditions. We found the SPIIF was able to detect both ICG and fluorescein under different depths of a semi-opaque colloid. Second, we found that a concentration as low as 0.5 g/ml of indocyanine green dissolved in plasma was detectable. Lastly, in a murine and human cancer model, the SPIIF was able to detect indocyanine green signal within tumors and generate a signal-to-background ratio (SBR) of 3.75. This study shows that a low-cost IFID can be made from commercially available parts. Second, this IFID is capable of in and ex-vivo detection of multiple fluorophores without sacrificing its small size or favorable ergonomics.

Intraoperative near-infrared fluorescence imaging and spectroscopy identifies residual tumor cells in wounds

“…27 Briefly, the device utilizes light from an air-cooled LED (SF1-740-iXF100, Edmund Optics, New Jersey, 742 nm, 46 W∕m 2 illumination intensity) to illuminate the sample. The bright-field light reflectance was imaged onto a CCD camera (PixelLink PL-B741EU), and the sample fluorescence was separated from the reflectance via a dichroic beam splitter and was imaged onto another (similar) camera; a bandpass emission filter (JI0SF4-11276, central wavelength 832 nm, width 10 nm, Edmund Optics, New Jersey) in front of the second camera reduced light contamination.…”

Intraoperative near-infrared imaging of mesothelioma

“…Both cameras acquire their images, permitting simultaneous visualization of anatomy (white light) and function (NIR light) (8). Although many commercial grade fluorescent imaging systems are available, we have demonstrated that a small portable interchangeable imager of fluorescence is much less expensive and still effective for detecting fluorescent tumors (11).…”

The Optical Biopsy

“…8 Positive and negative controls were used in all cases. At the time of optical biopsy, the surgeon graded the image as (þ) fluorescent or (À) fluorescent ( Fig.…”

“…3 Our group has been interested in developing a diagnostic technology that could provide specific histologic information about tissues within the confines of the operating room. [4][5][6][7][8][9] Such a technology would provide an important supplement to standard hematoxylin and eosin and immunohistochemistry. To achieve this goal, we postulated that molecular imaging may be a reasonable intraoperative diagnostic tool.…”