Nathan W Mehrtens et al 1997 Phys. Med. Biol. 42 997 doi:10.1088/0031-9155/42/6/001
The blanching process due to copper vapour laser treatment of port-wine stains
Nathan W Mehrtens
, Derek J Smithies, Philip H Butler and E Peter Walker§
We describe the causes and speed of transient blanching during copper vapour laser treatment of port-wine stains. Five watts of yellow (578 nm) light from a copper vapour laser was scanned over the lesion using a computer controlled scanning system.
The clinical response of the lesion to treatment is transient blanching, followed immediately by erythema. The clinical response of sclerosed vessels is different in that an intravascular coagulum is observed.
We measure the time taken for the lesion to blanch using two methods. First, high-speed photography is used to photograph the treatment process. Second, a photodiode measures the light re-emitted from the skin. Using illumination times of 3 to 5 ms and fluences of approximately 
, blanching times varied between 0 and 33 ms.
We conclude that the cause of the transient blanching is not thermal denaturation of either collagen or epidermal melanin. Rather it is the rapid expulsion of red blood cells from the treated vessels.
Our results have caused us to commence clinical trials using a new treatment protocol aimed at further improving the response of port-wine stains to copper vapour laser treatment.
- PACS
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85.60.Dw Photodiodes; phototransistors; photoresistors
- Subjects
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Instrumentation and measurement
- Dates
-
Issue 6 (June 1997)
Received 4 April 1995, in final form 4 March 1997
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The blanching process due to copper vapour laser treatment of port-wine stains
Nathan W Mehrtens et al 1997 Phys. Med. Biol. 42 997
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Synthetic aperture radar interferometry
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Fermion-field theory and configuration averaging. III. Off-diagonal disorder and bond CPA
A Mookerjee 1975 J. Phys. C: Solid State Phys. 8 2943
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An introduction to dispersive interactions
M M Taddei et al 2010 Eur. J. Phys. 31 89
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