Showing papers on "Imaging technology published in 1999"

Optical imaging technology in minimally invasive surgery. Current status and future directions.

Abstract: Optical engineering and imaging technology have played a major role in the evolving field of minimally invasive surgery (MIS) by making it possible to visualize the manipulation of tissue at remote internal sites We assess and review the optical imaging technology used during a variety of MIS procedures from an engineering perspective The field of MIS is evolving rapidly Optic-based technologies have the potential to further improve diagnostic capabilities of MIS Optical imaging technologies and instrument designs are discussed in relation to their current and future use in MIS procedures Technical limitations in imaging technology are described, along with potential solutions We review the current status and future role of optical imaging technology in MIS In the future, synergistic benefits from engineering, imaging technology, and MIS are likely to improve diagnostic ability and patient care

Biomedical imaging using optical coherence tomography

Abstract: Optical coherence tomography (OCT) is a recently developed optical imaging technique that performs high resolution, cross-sectional tomographic imaging of microstructure in biological systems. OCT is analogous to ultrasound B mode imaging except that it uses light instead of sound. OCT performs imaging by using low coherence interferometry to measure the optical backscattering of tissue as a function of echo delay and transverse position [1]. The resulting two-dimensional data set can be displayed as a gray scale or false color image. OCT functions as a type of "optical biopsy" to provide cross sectional images of tissue structure on the micron scale. OCT is a powerful imaging technology because, unlike conventional histopathology, which requires removal of a tissue specimen and processing for microscopic examination, OCT can provide images of tissue in situ and in real time, without the need for excision. OCT has originally been developed and applied by our group for tomographic diagnostics in ophthalmology [2,3]. OCT can provide images of the retina with resolutions of 10 p,m, one order of magnitude higher than conventional ultrasound. Working in collaboration with the New England Eye Center and MIT Lincoln Laboratory, we have developed a clinical prototype OCT instrument and examined over 5000 patients. The technology has been transferred to industry, and a commercial product was introduced into the ophthalmic market in 1996. Studies in ophthalmology show that OCT is especially promising for the diagnosis and monitoring of diseases such as glaucoma or macular edema associated with diabetic retinopathy where it provides quantitative information on disease progression. In many cases OCT has the ability to detect and diagnose early stages of disease before physical symptoms and loss of vision occur. Recent research on OCT has focused on developing technology to perform optical biopsy in internal medicine [4-6]. OCT at optical wavelengths in the near infrared where tissue scattering is minimized allows imaging to be performed to depths of 2-3 mm. Using solid state modelocked laser sources which can provide both short coherence lengths and high powers, high resolution and high speed imaging may be achieved. Image resolutions of 5-10 im and high speed acquisition of 250 x 250 pixel images at rates of 8 frames per second have been achieved. OCT imaging has been integrated with microscopy to perform imaging of specimens in vitro. A prototype single mode fiber optic catheter/endoscope with a diameter of 1 mm has been developed which can transluminally image internal tissue structures such as the respiratory tract, gastrointestinal tract, or arteries. In recent studies, catheter/endoscope based OCT imaging of internal organs in an animal model has been demonstrated [7]. Endoscopic OCT imaging in patients has also been demonstrated [8]. Ultrahigh resolution OCT has recently been developed and demonstrated. Kerr lens modelocked Ti:sapphire lasers have achieved sub-two cycle duration optical pulses with a corresponding bandwidth from 650 nm to 1000 nm [9]. Since the axial resolution of OCT is inversely proportional to the bandwidth of the light source, axial resolutions of 1 -2 im can be achieved. A novel C-scan focus tracking and image fusion technique has also been demonstrated to overcome depth of field limitations and permit 3 im transverse resolutions. This system can achieve subcellular level resolution and promises to be a powerful research tool in developmental biology and future clinical studies [10]. OCT is a promising and powerful medical imaging technique because it can permit the in situ visualization of tissue microstructure without the need to remove a specimen excisionally as in conventional biopsy and histopathology. The concept of nonexcisional "optical biopsy" provided by OCT and the ability to visualize tissue architectural morphology in real time under operator guidance can have many applications in several scenarios: 1) For situations where conventional biopsy is either hazardous or impossible, 2) Where biopsy has an unacceptably high false negative rate due to sampling errors, and 3) For guiding surgical intervention. This presentation will discuss technology and applications of this new imaging modality.

Early imaging of spinal trauma

Abstract: Spinal injury has the ability to maim and kill, but appropriate diagnosis and early treatment should result in minimization of secondary neurological injury and the restoration of the integrity of the spinal column. Rapid early diagnosis is essential and an impressive array of imaging technology is now available to the clinician. However, plain radiography remains the starting point for imaging of patients with potential spinal injury. This article reviews the role of plain radiography and the indications for further imaging, specifically with computerized tomography and magnetic resonance imaging.

High-resolution imaging of neoplastic lesions using optical coherence tomography

Abstract: A technology capable of imaging tissue, at or near the cellular level, could lead to the detection of neoplasias at earlier stages than currently possible. This could significantly improve patient outcomes, since once cancer becomes metastatic, cure is difficult. Optical coherence tomography (OCT), a recently developed imaging technology, has ben shown to achieve resolution in the cellular and subcellular range, and it could improve the diagnostic range of clinical imaging procedures. To assess the clinical applicability of OCT, neoplastic specimens from the urinary, gastrointestinal and female reproductive tract were imaged. Sharp differentiation of structures included the mucosa/submucosal/muscularis boundaries, epithelium, glands, supportive tissue, and intramural cysts. The ability of optical coherence tomography to image tissue microstructure at or near the cellular level make it a potentially powerful technology for minimally invasive assessment of tissue microstructure. The resolution of optical coherence tomography, which is greater than any current clinical imaging modality, make it particularly attractive for the assessment of early neoplastic changes.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Improved Three-Dimensional Eye Movement Measurement Using Smart Vision Sensors

Abstract: State-of-the-art imaging technology, based on video sensors, permits accurate three-dimensional measurement of eye movement (horizontal, vertical, torsional). The non-invasive nature of such imaging techniques is particularly attractive for use in the clinic, where due consideration must be given to patient comfort, and in those experimental situations where operating conditions preclude the use of more invasive techniques such as scleral search coils.