The development of minimally invasive surgery over the past 20 years has resulted in an increasing list of surgical operations in which the laparoscope is being used. While open surgery allows for tactile feedback and assessment of tumor masses and pulses, such assessments are extremely hampered during minimally invasive surgery. The determination of the organ's viability is a key component of operative exploration. Examining solid masses and tissue viability during minimally invasive surgery by interpretation of real-time optical spectroscopy is a feasible method of increasing the capabilities of minimally invasive surgery. We have recently reported on the ability to objectively measure real time renal perfusion using infrared (IR) imaging techniques in open donor nephrectomies. (Gorbach, Simonton et al., Am J Transplant 3:988-93, 2003) However, the poor image quality of the IR camera and non-integrated second generation IR laparoscope that are currently available has limited further clinical application. The development of a clinically useful integrated laparoscope with high resolution IR camera would allow for accurate intraoperative assessment of both tissue perfusion and solid organ masses. We propose to bring this technology to the clinic with the assessment of kidney perfusion during laparoscopic donor nephrectomy and partial nephrectomy for benign and malignant conditions. Over past year, the clinical protocol """"""""Infrared Image Guided Minimally Invasive Live Donor Renal Donation for Allotransplantation"""""""" (PI E. Elster, lead investigator A. Gorbach) was designed and approved. As a part of protocol implementation, technical requirements for five main elements of a new laparoscope were designed: 1. IR camera: This image-enhanced InSb-based cooled IR camera (640x512 pixels) is sensitive up to 5.5 microns, includes a carbon dioxide notch filter, and with f5.8 lenses has twice the sensitivity of previous cameras. The IR camera has been manufactured and is expected to be at NIH soon for testing. 2. A third generation laparoscope is being designed for assessment of tissue perfusion in the visible, mid-infrared and near-infrared spectrum. A 12-mm diameter, 34-cm long laparoscopic attachment (7 mm IR and 3.5 mm visible channels) will have independent focusing of both IR and visible channels. A new material for 12 optical elements will be used (ZeSe) that has much lower absorption than the currently available IR endoscope, which should increase thermal sensitivity. The designed laparoscopic attachment will be connected to the IR camera described above, and it is planned that the third generation of laparoscope will be ready for testing at the end of March 2006. 3. Near-infrared imaging: The visible light channel of the laparoscope will be utilized for both surgical observation and near-infrared imaging. For near-infrared, the channel will be connected with a CCD camera through a liquid crystal tunable filter to record the intensity of reflected light as a function of wavelength. Illumination fibers passed through the laparoscopic attachment will be connected to a standard tungsten-halogen lamp for laparoscopy and will illuminate the kidney in the region 380 - 1100 nm. A laptop computer will be connected with the CCD camera to collect images and to control the liquid crystal tunable filter. 4. Data fusion: Real time digital visible and IR images will be integrated with an Acadia Vision Processor (Sarnoff Corporation, PE). The cameras (an IR and a color visible range camera) will be mounted side by side, with overlapping fields of view, facing a field of about 10 square cm at a working distance between 30 - 100 cm. The goal of this phase is to be able to produce, in real time, a single image that is composed of the IR and visible images superimposed. 5. A Stand for intraoperative imaging and visualization has been designed and manufactured at DBEPS. As a spin-off of this IR project, two new protocols were designed with NCI over past year: """"""""Laparoscopic Prostatectomy and Nephrectomy in Mongrel Dogs"""""""" (PI Peter Pinto, MD, associate investigator A. Gorbach, Ph.D.) and """"""""Laparoscopic Partial Nephrectomy in the Pig: Evaluation of Two Hypothermia Techniques"""""""" (PI Peter Pinto, MD, associate investigator A. Gorbach, Ph.D.)
