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Laser treatment of port wine stains
News Update Laser treatment of port wine stains
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ort wine stain birthmarks can be removed using laser treatment individualized for a particular person rather than through guesswork-as was done until recently. This advance has resulted from a four-year collaboration between researchers at the California, University of Irvine’s Beckman Laser Institute and Medical Clinic and the Department of Energy’s Lawrence Livermore National Laboratory. Under the partnership, Livermore electronics engineer started Dennis Goodman working Beckman with researchers in 1993 and has continued to conduct research with the clinic’s medical staff. have Together, they converted a computer code, originally developed by Goodman to improve astronomical imaging, into a diagnostic tool that helps doctors pinpoint the precise laser parameters needed to remove port wine stains on an individual patient basis. A birthmark that affects about 12000 Americans born each year, port wine stains result from an excessive number of oversized blood vessels near the skin’s surface. Previously, doctors treated which the discolourations, range from light pink to deep purple, by simply estimating the laser energy and pulse length needed to remove them. ‘It was total guesswork’, said Stuart Nelson, an associate medical director at the Beckman Laser Institute, ‘The way treatments were done before was to try different parameters almost randomly.’ He added, ‘We are the only researchers who are using these diagnostic techniques to remove port wine stains.’ Clinical trials using the complete, three-dimensional diagnostic technique to treat patients have started and will continue for about a year.
Already, parts of the diagnostic technique have been employed on port wine stain models, and for about a year on people with port wine stains, using one-dimensional computer codes. The diagnostic technique starts with a subtherapeutic laser pulse that is directed onto a patient’s skin and blood vessels. An infrared camera system records images as the laser heats the skin’s melanin-the material that gives skin its colour-and the blood. As the laser heat flows back to the skin’s surface, it helps identify the location, depth and other data for the port wine stain blood vessels. This data, in turn, is converted into useful clinical images by Goodman’s algorithm. (This algorithm was developed at LLNL for use in speckle interferometry, to reduce the effects of atmospheric turbulence in order to improve the resolution of ground-based telescopes.) Another key part of the individualized treatments has been the development by a Palo Alto company of a new laser to treat port wine stain patients. Each week the Beckman Laser Institute uses lasers to treat and remove port wine stains from five to ten patients-but now with precise measurements they have not had before. These measurements are helpful because it takes precise laser energies to remove properly different port wine stain birthmarks without damaging normal skin pigmentation or producing scars. A promising feature of the research is that only one sequence of measurements allows physicians to obtain the data they need to treat individual port wine stains using Goodman’s code. Factors that cause variations in individual port wine
Optics & Laser Technology Vol29 No 3 1997
stains include blood flow, the size of the blood vessels, the number of blood vessels, their depth and their absorption characteristics. Goodman’s code generates images that permit Beckman researchers to enter data about a port wine stain and then determine how much laser energy to use. ‘This is particularly valuable because port wine stains vary not only from one person to the next, but from one location to another on the
same patient,’ said Tom Milner. assistant professor of surgery and an optical physicist at Beckman. ‘If you’re treating a patient who has a stain that goes very deep, without the code. the doctor does not know how deep the port wine stain is.’ Milner said. ‘The code allows us to figure that out.’ Lnwrence Livermore National Laboratory, PO Bou 808, Livermore, Cmlifornia 94551, USA
UV broadband antireflection coatings
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ltraviolet broadband antireflection coatings which can efficiently transmit the entire 193-353 nm wavelength range using only two optical elements have been developed by Acton Research Corporation (ARC) and are available in the UK from AG Electra-Optics. These coatings are optimized for low reflectance and maximum transmittance. The average reflectance for the wavelength range 193-248 nm is 0.4&0.8%, and 0.20.6% for the 248-355 nm range.
ARC’s ultraviolet antireflection coatings are durable, electron beam deposited dielectrics, designed to minimize reflections that normally occur from uncoated surfaces of substrates. These low absorption coatings are suitable for increasing the transmittance properties of lenses, and for reducing the second surface reflections of beamsplitters. AC Electra-Optics Ltd. Tarparley Business Centre, Tarparley, Cheshire C W6 9 Ii Y, UK. Fax: + 44 (0) I829 733679
Beer analyser
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ocated at the back of the tongue, the bitterness sensation is one of four principal taste sensations. And the bitterness of beer is derived from the bitter tasting hop isoalpha acids. Using the fluorescence properties of iso-alpha acids, and the quenching effect produced from colour dependent absorption, the BeerProbe from Instruments SA (UK) can analyse the bitterness and colour of beer.
The fluorescence emission of the beer is measured against known standards enabling accurate in-line values of colour and bitterness to be rapidly obtained. The patented fluorescence technique was developed in conjunction with Whitbread plc, a UK brewer. Instruments SA (UK) Ltd, 2--4 Wigton Gardens, Stanmore, Middlesex HA7 IBG, UK. Fax: t44 (O)fSl 204 6142
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P
ort wine stain birthmarks can be removed using laser treatment individualized for a particular person rather than through guesswork-as was done until recently. This advance has resulted from a four-year collaboration between researchers at the California, University of Irvine’s Beckman Laser Institute and Medical Clinic and the Department of Energy’s Lawrence Livermore National Laboratory. Under the partnership, Livermore electronics engineer started Dennis Goodman working Beckman with researchers in 1993 and has continued to conduct research with the clinic’s medical staff. have Together, they converted a computer code, originally developed by Goodman to improve astronomical imaging, into a diagnostic tool that helps doctors pinpoint the precise laser parameters needed to remove port wine stains on an individual patient basis. A birthmark that affects about 12000 Americans born each year, port wine stains result from an excessive number of oversized blood vessels near the skin’s surface. Previously, doctors treated which the discolourations, range from light pink to deep purple, by simply estimating the laser energy and pulse length needed to remove them. ‘It was total guesswork’, said Stuart Nelson, an associate medical director at the Beckman Laser Institute, ‘The way treatments were done before was to try different parameters almost randomly.’ He added, ‘We are the only researchers who are using these diagnostic techniques to remove port wine stains.’ Clinical trials using the complete, three-dimensional diagnostic technique to treat patients have started and will continue for about a year.
Already, parts of the diagnostic technique have been employed on port wine stain models, and for about a year on people with port wine stains, using one-dimensional computer codes. The diagnostic technique starts with a subtherapeutic laser pulse that is directed onto a patient’s skin and blood vessels. An infrared camera system records images as the laser heats the skin’s melanin-the material that gives skin its colour-and the blood. As the laser heat flows back to the skin’s surface, it helps identify the location, depth and other data for the port wine stain blood vessels. This data, in turn, is converted into useful clinical images by Goodman’s algorithm. (This algorithm was developed at LLNL for use in speckle interferometry, to reduce the effects of atmospheric turbulence in order to improve the resolution of ground-based telescopes.) Another key part of the individualized treatments has been the development by a Palo Alto company of a new laser to treat port wine stain patients. Each week the Beckman Laser Institute uses lasers to treat and remove port wine stains from five to ten patients-but now with precise measurements they have not had before. These measurements are helpful because it takes precise laser energies to remove properly different port wine stain birthmarks without damaging normal skin pigmentation or producing scars. A promising feature of the research is that only one sequence of measurements allows physicians to obtain the data they need to treat individual port wine stains using Goodman’s code. Factors that cause variations in individual port wine
Optics & Laser Technology Vol29 No 3 1997
stains include blood flow, the size of the blood vessels, the number of blood vessels, their depth and their absorption characteristics. Goodman’s code generates images that permit Beckman researchers to enter data about a port wine stain and then determine how much laser energy to use. ‘This is particularly valuable because port wine stains vary not only from one person to the next, but from one location to another on the
same patient,’ said Tom Milner. assistant professor of surgery and an optical physicist at Beckman. ‘If you’re treating a patient who has a stain that goes very deep, without the code. the doctor does not know how deep the port wine stain is.’ Milner said. ‘The code allows us to figure that out.’ Lnwrence Livermore National Laboratory, PO Bou 808, Livermore, Cmlifornia 94551, USA
UV broadband antireflection coatings
U
ltraviolet broadband antireflection coatings which can efficiently transmit the entire 193-353 nm wavelength range using only two optical elements have been developed by Acton Research Corporation (ARC) and are available in the UK from AG Electra-Optics. These coatings are optimized for low reflectance and maximum transmittance. The average reflectance for the wavelength range 193-248 nm is 0.4&0.8%, and 0.20.6% for the 248-355 nm range.
ARC’s ultraviolet antireflection coatings are durable, electron beam deposited dielectrics, designed to minimize reflections that normally occur from uncoated surfaces of substrates. These low absorption coatings are suitable for increasing the transmittance properties of lenses, and for reducing the second surface reflections of beamsplitters. AC Electra-Optics Ltd. Tarparley Business Centre, Tarparley, Cheshire C W6 9 Ii Y, UK. Fax: + 44 (0) I829 733679
Beer analyser
L
ocated at the back of the tongue, the bitterness sensation is one of four principal taste sensations. And the bitterness of beer is derived from the bitter tasting hop isoalpha acids. Using the fluorescence properties of iso-alpha acids, and the quenching effect produced from colour dependent absorption, the BeerProbe from Instruments SA (UK) can analyse the bitterness and colour of beer.
The fluorescence emission of the beer is measured against known standards enabling accurate in-line values of colour and bitterness to be rapidly obtained. The patented fluorescence technique was developed in conjunction with Whitbread plc, a UK brewer. Instruments SA (UK) Ltd, 2--4 Wigton Gardens, Stanmore, Middlesex HA7 IBG, UK. Fax: t44 (O)fSl 204 6142
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