| PRACTICE PEARLS
tissue. Therefore, higher fluences are used for a greater effect on larger vessels and lighter pigmented lesions. For a more limited and conservative effect and a safer treatment, particularly in darker skin types, a lower fluence is selected. Changing the pulse duration also has an
effect on the target lesions and skin. For the same fluence, a shorter pulse duration delivers the same amount of light energy over a shorter time producing a higher peak temperature in the epidermis. The same fluence delivered over a longer pulse duration (e.g. 15 ms or greater) produces a lower peak temperature in the epidermis. Thus, shorter pulse durations (less than 15 ms) are better at heating superficial pigmented lesions. Longer pulse durations for the same fluence
make a treatment more conservative thus protecting skin with more pigmentation as in skin type IV and V. Longer pulse durations also allow higher fluence to be delivered over a longer period of time without creating excessively high temperatures in the epidermis. Higher fluences are necessary when treating larger vessels and deeper structures such as hair follicles. Longer pulse durations are selected for higher fluences and in darker skin types for a safer treatment.
Temperature The effect of changing the contact cooling temperature on target lesions and skin can be thought of in the following way. The lower the temperature of the crystal in contact with the skin, the cooler the starting temperature of the epidermis; the cooler the temperature of the epidermis, the lower the peak temperature for the same fluence and pulse duration; the lower the peak epidermal temperature with each
Figure 1 A) Before, and B) after 3 treatments with broadband light for photo damage/dyschromia
pigmented lesions are being treated. Lower contact crystal temperatures are used when there is greater epidermal melanin as in skin types IV and V and when high fluences are used to treat vascular or deeper dermal targets and it is necessary to protect the epidermis from excessive heating.
Spot size Another parameter that is a factor relevant to the effectiveness of a treatment is the spot size of the crystal in contact with the treatment area. Some devices, such as Sciton’s BBL™ (Palo Alto, CA), allow the operator to change the spot size through the use of treatment applicators that fit over the crystal, reducing the size of the treated area and allowing a more focused treatment. A smaller spot size permits the operator to use higher fluences that are focused on specific vascular and pigmented target areas producing the thermal effect necessary to clear the lesion yet containing the thermal effect within the target zone, while sparing non-target areas. Smaller spot adaptors or applicators also permit the treatment of
While proper choice
of parameters is essential to effectively treat
pigmented and vascular lesions, treatment
technique is equally important.
pulse of broad spectrum light, the more conservative the effect and the safer the treatment. Conversely, the higher the starting temperature of the crystal in contact with the epidermis, the greater the peak temperature of the epidermis and the greater the epidermal effect. Higher contact crystal temperatures are desirable when lighter or more resistant
harder to reach areas such as the medial canthus, nasal tip, and infrabrow skin. Each pulsed light device has different
parameters that have been worked out to treat pigmented and vascular lesions. While there is no one optimal parameter for every type of vascular or pigmented lesion, in general, vascular lesions respond most effectively to
types of benign pigmented lesions, such as ephelides, solar lentigoes, and thin pigmented seborrhoeic keratosis. Shorter pulse durations (5 and 10 ms) are more effective for pigmented lesions than longer pulse durations. Additionally, higher contact cooling temperatures, such as 20–25°C are more effective at heating collections of epidermal
prime-journal.com | January/February 2015 ❚ 51
higher fluences, pulse durations of 10 to 20 ms, and cut-off filters that are 560 nm. The 515 nm cut-off filters can be used for smaller and more superficial vessels, while the 590 nm cut-off filter is used for skin type IV patients. As a general guideline, the larger the vessel the higher the fluence and the longer the pulse duration. Contact cooling is another factor that enters into consideration for treatment of both vascular and pigmented lesions. First, contact cooling provides protection of the epidermis, especially when a higher fluence is used or a lower numbered cut-off filter (515 nm or 560 nm) is selected. Second, a slightly higher contact temperature may be more effective at clearing superficial and smaller vessels as well as generalised erythema (e.g. raising the contact cooling temperature from 15°C to 20°C). Benign pigmented lesions respond very well
to pulsed light treatments with complete to nearly complete clearance expected in one or two treatments. In general, the lower wave length cut-off filters, such as 515 nm filter for skin types I through III and 560 nm filter for skin type IV patients are most effective for all
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64