Biomedical Engineering Reference
In-Depth Information
A clinical and histologic clearance of 100% was obtained in the
small AK lesions group during the 1-year follow-up period.
In the cohort with larger AK lesions, six of the 20 patients
experienced residual lesions or recurrence. These fi ndings are
consistent with the poor penetration of ALA through thicker,
hyperkeratotic lesions and resulting lower AK clearance rates.
superfi cial BCC (87). Complete clearance rate for AKs after one
and two treatments were 77% and 99%, respectively. However,
the recurrence rate at 12 months was 28%. Mild stinging, tin-
gling, or burning was reported by most patients. Another study
also treated patients of mixed diagnoses. AKs, BCC, and SCC-in
situ in 762 patients were treated by Moseley and coworkers (88).
Ninety-two percent of AKs cleared after two treatments, with
100% clearance after three PDT sessions. Finally, Clark et al.
(46), using a topical 20% ointment, treated 207 patients with
483 lesions. An impressive 91% clearance was observed clini-
cally at a median of 48 weeks following treatment.
Incoherent Red Light Sources
Metal halide lamps emitting a spectrum of light from 580 to
740 nm have been used in numerous ALA-PDT studies. Using
the Waldmann/PDT 1200 lamp, 36 lesions in 10 patients were
treated topically with ALA for 6 hours under occlusion fol-
lowed by red light irradiation. At 28 days following treatment,
the clearance of face and scalp lesions was 71%. Patients expe-
rienced pain and burning and mild postprocedure erythema.
Several studies followed shortly thereafter reporting clear-
ance rates of facial AKs between 77% and 99%. Karrer et al.
(84) treated 24 patients and 200 scalp and facial lesions with a
clearance rate of 84% at 1 month following PDT. Kurwa et al.
(70) used a metal halide lamp for ALA-PDT to treat the dorsal
hands, resulting in a 79.5% decrease in AKs lesions. Itoh and
coworkers (85) treated Japanese patients with AKs on the face,
neck, and extremities. With two or more treatments, clearance
rates at 12 months were higher for lesions on the head and neck
(81.8%) compared with the extremities (55.6%). No serious
adverse effects were reported in these patients with darker skin
types. Markham and Collins (48) treated four patients with
topical ALA under occlusion for 4 hours for scalp AKs. Three
patients cleared following treatment, and the remaining
patients had signifi cant improvement at 6 months. Varma et al.
(86) treated 88 patients with ALA-PDT using a red lamp for a
variety of diagnoses, including AKs (127 lesions), BD (76), and
Broadband/Visible Light Sources
The earliest light sources used for the treatment of AKs during
the modern PDT era produced unfi ltered, noncollimated light
for photoactivation. Following the work by Kennedy et al. (74),
Wolf (21) in 1993 reported on the complete clearance of nine
AKs after one round of treatment using a slide projector for a
light source. Fink-Puches and coworkers (89) used a modifi ed
halogen slide projector with four fi lter cutoffs at 515, 530, 570,
and 610 nm. AK lesions of the head, neck, forearms, and dorsal
hand lesions were treated with 20% ALA for 4 hours under occlu-
sion prior to light irradiation. Overall, complete response after
one treatment was 64%, increasing to 85% with a second treat-
ment. Head and neck lesions responded better than extremity
lesions. Head and neck complete response rates varied from 93%
to 100% depending on the spectrum of light used for treatment.
Forearms and hands had a lower response rate ranging from 33%
to 53%. Overall complete response rate at 36 months was 23%
for fi ltered light and 71% for full spectrum light.
IPL devices (Fig. 10.6) are powerful tools for treating the
signs of photoaging. Their use in photorejuvenation with
(
A
)
(
B
)
Figure 10.6
IPL devices are particularly effective in ALA-PDT for photorejuvenation. Cooled conductive gel and forced air cooling units minimize discomfort dur-
ing treatment. (
A
) Patient with basosquamous carcinoma on the shoulder before and 8 months after two sessions of ALA-PDT (
B
).
Abbreviations
: ALA-PDT, ami-
nolevulinic acid-photodynamic therapy; IPL, intense pulsed light.
Source
: Image of Lumenis One IPL device, courtesy of Lumenis, Inc., Santa Clara, California, USA.
