How Lasers Got Their Start in Medical Technology

Gary Hayes, Laser Components USA, Inc.
The healing power of light has been known for millennia. In fact, it is said that even the Greek and Ancient Egyptians once built solariums. Rooms equipped with colored glass were used to cure illnesses.
Einstein‘s research results on stimulated emissions impressed medical scientists as early as 1917 – even if they only had a rough sense of how this light would be used later on in treatment.
Theodore H. Maiman introduced the first functioning laser at Hughes Research Labs: a Rubin laser with a wavelength of 694 nm. [1]

History

Beyond Borders

The First Medical Laser

A laser was first used in medicine in 1961: At the Columbia Presbyterian Medical Center in Manhattan, Dr. Charles J. Campbell, et al., used a Rubin laser to destroy a tumor on a patient’s retina [2]. The Rubin laser was also used by Dr. Leon Goldman, who published studies on the effect of laser beams on the skin in 1963 [3] and used the beam to remove tattoos. Goldman is considered a pioneer. He began his research in 1960 and, early on, founded the American Society of Laser Medicine. At the optoelectronics conference in Munich in 1979, he was officially honored as the “Father of Laser Medicine” [4].

The 1980s

When LASER COMPONENTS started its production of high-power laser optics with high damage thresholds in 1986, laser medical technology was being used for very different disciplines. The progressive requirements in this market increased the demand for all types of high-quality lasers.
The optical components used in the laser are critical elements. They affect not only the design of the device but the quality of the laser beam as well. LASER COMPONENTS recognized this new market and seized the opportunity to produce custom, high-quality laser optics, resulting in the OEM business it is today.

Minimally Invasive Surgery

Today, lasers are often used in minimally invasive surgery (MIS): German-born Kurt Semm is considered the initiator of state-of-the-art endoscopic surgery. He first carried out laparoscopic appendix surgery at the University Hospital of Kiel in 1980 [5]. Optoelectronics facilitated the breakthrough of endoscopic procedures: CCD cameras made it possible to record live images inside the body on a monitor.

Laser Technology in Endoscopy

Laser technology was also quickly applied to endoscopic applications. In the early 1990s, this technology experienced a boom and was acquired as a surgical tool in state-of-the-art operating equipment in hospitals. This method, which is also known as keyhole technology, has immense advantages: The tissue can be treated in a gentle and targeted manner without damaging the surrounding area. Patients can look forward to a quick recovery, reducing the length of hospital stays.

Medical Laser Applications

Lasers not only achieve extraordinary results in MIS, but they are used in many areas of medicine as well.

Diagnosis & Usecases

Beyond Borders

Fluorescence

Lasers can be used in the excitation of fluorescent marker substances, which are required in tissue analysis (cells) and physiological testing (e.g., the analysis of brain activity) [6]. Excitation is carried out via UV diode lasers.

Optical Tweezers

Optical tweezers are used, for example, to examine movements in individual muscle fibers. Laser sources in the near infrared range are used that have a TEM00 beam profile. [6], [7]

OPHTHALMOLOGY

Lasers are used to correct ametropia. Femto Lasik procedures which use excimer lasers and femtosecond lasers are described in the following pages.

CARDIOLOGY

Stents are cut from metal. Laser material processing with ultrashort pulse lasers makes it possible to create very fine structures.

DERMATOLOGY

Pigment changes, skin changes, or tattoo removal: Rubin or pulsed dye lasers are often used in dermatology and aesthetic medicine to treat blemishes or extensive redness. Spider veins can be treated with long-pulsed Nd:YAG lasers, and the ablation of liver spots or acne scars can be carried out with CO₂ lasers.

KIDNEY STONES

If extracorporeal shock wave therapy (ESWT) is not effective or if large kidney stones have to be removed, they can be shattered in a minimally invasive manner with a Hol:YAG laser.

TUMOR REMOVAL

Lasers are used successfully in surgical oncology: Ho:YAG or Tm:YAG lasers are used to cut, for example, tumors from tissue in the urethra, bladder, ureter, or kidneys. [8]

Sources

Beyond Borders

[1] F. K. Kneubühl, M. W. Sigrist: Laser. Teubner, 1991 3. Aufl. S. 4
[2] Lasers in Ophtalmology: Basic, Diagnostic, and Surgical Aspects; 2003, Kugler Publications, S. 115
[3] Goldman L, Blaney DJ, Kindel DJ, et al (1963) Effect of the laser beam on the skin: Preliminary rport. J Invest Dermatol 40:121-122
[4] idnps.com/basics/history-of-aesthetic-laser/1-2-birth-of-medical-laser-in-the-1960s-background/
[5] www.ag-endoskopie.de/geschichte-der-endoskopie-ii
[6] Prof. Dr. Dieter Suter; Experimentelle Physik III, Einführung in die Medizintechnik, S. 242 ff., 2015
[7] lpmt.biomed.uni-erlangen.de/mediafiles/Teaching/ILS_Bachelor/BiophysModul/Praktikum%20optische%20Pinzette.pdf (Zugriff: 20.10.2016)
[8] www.jenasurgical.com/de/urologie/ (Zugriff: 20.10.2016)

Product Overview

Laser Optics for medical lasers

Aspherical lenses correct aberrations, which in monochromatic light include image sharpness errors and distortion.

A typical application of these lenses is the focusing of a collimated beam onto an optical fiber.

Cavity end mirrors are used to generate the laser beam in the resonator.

Resonator end mirrors, also known as cavity mirrors, are designed to have high reflectivity at the desired laser wavelength in order to maximize the efficiency of the laser.

ROUND AND RECTANGULAR CYCLINDER LENSES ARE USED TO CREATE LINES / BEAM EXPANSIONS IN ONE DIRECTION.

We offer plano-concave and plano-convex cyclindrical lenses in rectangular, square, and round form.

DIAGNOSTIC BEAM SPLITTERS FOR PROCESS MONITORING

Dichroic mirrors separate or combine two or more beams of different wavelengths in the desired ratio and enable process monitoring on the operating level in several wavelength ranges, as well as beam diagnostics. Their complex design enables multiple transmission and reflection ranges.

combine or separate two or more beams with different wavelengths.

Customized dichroic mirrors that are suitable for your individual application are manufactured upon request.

The degree of reflection slopes from the center of the optic in a Gaussian distribution.

Gaussion mirrors are used in unstable resonators - mostly as meniscus lenses with an integrated wedge to avoid back reflections despite of antireflection coatings.

Optimized for high-power lasers with intense pulse energies or high average powers

Mirrors for high-power lasers are high-precision optical components that direct or focus the laser beam. Thanks to a dielectric coating, the mirrors reflect the laser beam efficiently and withstand the high thermal load caused by the laser energy.

Protective windows are used during laser material processing to protect against material splashes.

Protective windows are the last optics to be used in front of the work area. They protect high-quality laser optics from material splashes during cutting, welding, drilling, structuring, marking and additive manufacturing. Protective windows are available in a variety of shapes and qualities.

FOR SPLITTING INTO ONE OR MORE DEFINED PARTIAL BEAMS.

When working with lasers, it is often necessary to split a laser beam into two or more defined partial beams. There are a variety of beam splitters for these applications, with different advantages and disadvantages. Dielectrically coated beam splitters have a high laser damage threshold.

Transmissive Plano-Parallel Plates WITH MINIMAL DISTORTION, SCATTERING OR ABSORPTION

Optical windows for laser applications are flat, transparent substrates made of materials with excellent optical properties. They are usually optimized to provide maximum transmission in a specific wavelength range providing low reflection and absorption at the same time.