Optimising the design of a broad‐band light source for the treatment of skin

Abstract

Phototherapy has become a treatment of choice in many areas of medicine. Light can be used to deliver energy to tissue selectively targeting specific structures in order to induce the desired therapeutic outcome. The choice of optical parameters for a specific application is not simple. Wavelength, energy, exposure time and fluence can be varied and induce a wide range of tissue effects. The treatment of the skin with light is probably the one phototherapy application that is most developed in terms of technology and market maturity. White light systems are extensively used to address a range of skin conditions. However, different conditions have different physiology and hence require differing optical parameters. The technology standard is based upon systems, which have a number of different optical filters allowing the output to be tailored to the specific application. This paper discusses the advantages of a different type of system, namely the iPulse i300 (Cyden Ltd, Swansea, UK), which uses a single dichroic reflectance filter and whose optical output is changed by varying other parameters in a carefully controlled manner.

Hair removal with a novel, low fluence, home-use intense pulsed light device

“…Traditional IPL systems, however, have nonuniform pulse characteristics with a wavelength shift in a time-dependent manner through the pulse, whereby there is a shift from red/infrared to shorter blue wavelengths in the mid-pulse, back to longer red/infrared towards the end of the pulse (4). A new type of IPL system with a miniaturized and patented power-supply has been developed.…”

Clinical and microscopic evaluation of long‐term (6 months) epilation effects of the ipulse personal home‐use intense pulsed light (IPL) device

“…This process is believed to lead to thermal damage to the pluripotential stem cells surrounding the hair follicles and results in suppression of further hair growth. Partial discharge (‘square pulse’) IPLs like the one used in this study have the advantage of a constant broadband spectrum output and thus many wavelengths contribute to denaturing the key proteins found in the hair structure, while hair removal lasers only emit a monochromatic light and some lasers may be limited in their suitability for certain skin and hair types 9 …”

“…Partial discharge ('square pulse') IPLs like the one used in this study have the advantage of a constant broadband spectrum output and thus many wavelengths contribute to denaturing the key proteins found in the hair structure, while hair removal lasers only emit a monochromatic light and some lasers may be limited in their suitability for certain skin and hair types. 9 The growing demand for simple and effective home-use, hair removal devices has aroused commercial interest among manufacturers and there is now a proliferation of lasers and IPL systems on the market, some of which are far from accomplishing what is expected from professional photoepilation. Consequently, an objective assessment of light-based home-use systems is needed to check their performance and to validate the effects of hair removal that can only be carried out through controlled clinical studies and the observation of histological effects on the hair structure.…”

Relevance of the structure of time‐resolved spectral output to light‐tissue interaction using intense pulsed light (IPL)

“…These parameters may include: exposure time of intense light (pulse duration or total duration of sub-pulses) in millisecond, energy density (fluence) in J/cm 2 , and cut-off filters to eliminate unwanted wavelengths. Each of these parameters is important to produce the most desirable thermal profile in the melanin of the hair follicle or epidermis, or in the haemoglobins in the blood vessel, whichever is the major chromophore being targeted.…”

“…1a and 2a). This effect of 'spectral jitter' during the pulse means that the optical output not only varies during the pulse but may also differ significantly from one energy setting to another [1][2][3].…”