An imaging system for performing forward scanning imaging for application to therapeutic and diagnostic devises used in medical procedures. The imaging system includes forward directed optical coherence tomography (OCT), and non-retroreflected forward scanning OCT. Also interferometric imaging and ranging techniques and fluorescent, Raman, two-photon, and diffuse wave imaging can be used. The forward scanning mechanisms include a cam attached to a motor, pneumatic devices, a pivoting device, piezoelectric transducers, electrostatic driven slides for substantially transverse scanning; counter-rotating prisms, and offset lenses are used for arbitrary scanning. The imaging system of the invention is applied to hand held probes including probes integrated with surgical probes, scalpels, scissors, forceps and biopsy instruments. Hand held probes include forward scanning lasers. The imaging system is also applicable to laparoscopes and endoscopes for diagnostc and therapeutic intervention in body orifices, canals, tubes, ducts, vessels and cavities of the body. The imaging system includes application to surgical and high numerical aperture microscopes. An important application of the invention is implantation of the optical probe for periodic or continuous extraction of information from the tissue site where implanted.

Methods and apparatus for forward-directed optical scanning instruments

Ultra-small optical probes comprising a single-mode optical fiber and a lens which has substantially the same diameter as the optical fiber. The optical fiber and lens are positioned in a probe housing which is in the form of an insertional medical device such as a guidewire. Connector elements are provided to facilitate the attachment of the probe to an optical system and the quick disconnection of the probe from the optical system. The probe is used to obtain optical measurements in situ in the body of an organism and can be used to guide interventional procedures by a surgeon.

Ultra-small optical probes, imaging optics, and methods for using same

The present state of high-resolution displacement measuring interferometry is reviewed. Factors which determine the accuracy, linearity and repeatability of nanometre-scale measurements are emphasized. Many aspects of interferometry are discussed, including general metrology and alignment errors, as well as path length errors. Optical mixing and the nonlinear relation between phase and displacement are considered, as well as the influence of diffraction on accuracy. Environmental stability is a major factor in the repeatability and accuracy of measurement. It is difficult to obtain a measurement accuracy of 10-7 when working in air. Several approaches to improving this situation are described, including multiwavelength interferometry. Recent measurements of the short- and long-term frequency stability of lasers are summarized. Optical feedback is a subtle, but important source of frequency destabilization, and methods of detection and isolation are reviewed. Calibration of phase measuring electronics used for subfringe interpolation is included. Progress in 'in situ' identification of error sources and methods of validating accuracy are emphasized.

http://iopscience.iop.org/article/10.1088/0957-0233/4/9/001/pdf

Recent advances in displacement measuring interferometry

Treatment of Tracheobronchial Lesions by Laser Photoresection

An apparatus for performing high speed scanning of an optical delay and its application for performing optical interferometry, ranging, and imaging, including cross sectional imaging using optical coherence tomography, is disclosed The apparatus achieves optical delay scanning by using diffractive optical elements in conjunction with imaging optics In one embodiment a diffraction grating disperses an optical beam into different spectral frequency or wavelength components which are collimated by a lens A mirror is placed one focal length away from the lens and the alteration of the grating groove density, the grating input angle, the grating output angle, and/or the mirror tilt produce a change in optical group and phase delay This apparatus permits the optical group and phase delay to be scanned by scanning the angle of the mirror In other embodiments, this device permits optical delay scanning without the use of moving parts

Interferometeric imaging with a grating based phase control optical delay line

Summary The conventional management of certain problems in the aerodigestive tract has been either inconvenient or ineffective. Seventy-five cases have been treated with the continuous wave CO 2 laser in an attempt to identify the advantages and limitations of laser surgery. It has been found that the CO 2 laser provides a practical method of tissue ablation or excision which can be carried out with excellent control. The laser beam is directed with a handpiece in the oral cavity, with the surgical microscopic laser attachment in the nose, pharynx, and larynx, and with the endoscope-bronchoscope assembly in the tracheobronchial tree. Laser surgery appears to be most valuable when precise surgery is needed to preserve function.

Laser surgery in the aerodigestive tract

Endotracheal and endobronchial carbon dioxide laser surgery can be carried out using standard ventilating bronchoscopes, a recently developed laser endoscope attachment and a 50W CO2 surgical laser unit. General anesthesia, using nonflammable anesthetics, is delivered through the side arm of the ventilating bronchoscope; the tidal flow of gases keeps the trachea and bronchi free of steam and smoke. The technique has been particularly helpful in the bloodless removal of recurrent papillomas from the trachea and main stem bronchi of ten children with tracheostomies. While three of the patients have gone into remission following laser excision, the method cannot be curative of itself. There were no complications attributable to the carbon dioxide laser surgery, per se, but constant vigilance must be exercised as with all laser surgery. As instrumentation becomes refined the technique will have wider application in the management of tracheobronchial disease.

Bronchoscopic Carbon Dioxide Laser Surgery

Derivation of a frequency—sensitive signal from a gas laser in an axial magnetic field

A surgical laser system for performing surgical operations upon a patient. The system includes a laser which could be a continuous wave laser which can be continuously energized if desired, and means for continuously illuminating the work site (patient tissue). There is further provided means for concurrent observation of the site and exposure of the site to the laser beam. Additionally, novel use of a light-transmissive pellicle provides a protective physical barrier between the inclement atmosphere associated with the surgical work site (moisture, mucus) and expensive optics including a beam splitter employed in the endoscope.

Endoscopic surgical laser system

A micro-surgical laser system wherein a carbon dioxide (CO2) laser is fixedly attached to the freely positionable combination of an operation or surgical microscope and a stereo laser endoscope. This arrangement completely eliminates the need for a bulky and/or complex laser-beam-guiding articulated arm apparatus. The laser features novel and light-weight construction, and novel means for heat exchanging.

Robert Alvin Wallace

Papers

Laser surgery in the aerodigestive tract

Bronchoscopic Carbon Dioxide Laser Surgery

Derivation of a frequency—sensitive signal from a gas laser in an axial magnetic field

Endoscopic surgical laser system

Micro-surgical laser system