EVALUATION OF
INTENSE PULSED LIGHT DEVICES
USING STANDARDIZED
METHODOLOGY
G. Town1, C. Ash2
1RPA2000
Laser Protection Adviser, Haywards Heath, United Kingdom
2OptoElectronic Engineer, Swansea, Wales, United Kingdom
The following potential conflict of interest relationships are germane to my presentation:
Financial grant, equipment, consulting fees
and travel expenses paid by CyDen Ltd.
• Status of FDA devices used for the material
being presented:
– NA/Non-Clinical
• Status of off-label use of devices, drugs or
other materials that constitute the subject of
this presentation:
– NA/Non-Clinical
Introduction
• 18 different devices from 15 different manufacturers
and 36 applicators (different cut-off filters) from USA, UK,
Israel, Sweden, Switzerland, China and Italy were tested
by the authors.
• Data was gathered on-site between patient appointments
over a 6-month period in clinics where devices were
in daily use.
• Manufacturers’ information was collected from user
manuals, company web sites and literature.
Comparing Fluence Values
30 IPL applicators were measured at maximum fluence of which 11 were
more than 20% below and 8 were more than 10% above fluence levels
given on the device display or claimed in user manuals, even where brandnew lamps were tested.
Comparing Fluence Values
9 IPL devices out of 18 had applicators that were outside of the standard
formedical Class 4 lasers (> ±20%)
Comparing Pulse Duration
Study
Ref
Stated Pulse
Duration (ms)
Measured Pulse
Duration (ms)
Study
Ref
Stated Pulse
Duration (ms)
Measured Pulse
Duration (ms)
A
3 x 10 ms = 30
3 x 6 ms = 18
I
short:5.5/5.5 (2)
5.5/5.5 (2)
A1
14
14.5
med:3.6/3.6/3.6 (3)
4.0/4.0/4.0 (3)
2 x 2.5 ms = 15
2 x 3 ms = 15.5
long:3.6/3.6/3.6 (3)
4.5/4.5/4.5 (3)
B
5
15-17
J
40
40
C
5
15-17
K
34.8
37
D
50
51
123
121
10-15
no data
15 black
2.2
E
10-50
10-51 ms
15 blonde
5
F
20-150
missing pulses
3
3
20-151
missing pulses
5
5
10
6
35
132
20
6.6
35
132
20
8.7
10
24
5.5/5.5/5.5
5.4 6.4 7.0
O
40
42
Q
30/40/50
30/40/50
G
H
L
M
N
Only 14 of 29 pulse duration measurements were within ±20% of the
manufacturers stated or system-displayed values.
Comparing Electrical Discharge Shape
IPL ‘E’
IPL ‘A’
IPL ‘G’
IPL ‘Q’
IPL ‘C’
IPL ‘B’
Only IPLs ‘E’ and ‘G’ exhibited a true single square pulse shape confirming
that they used partial discharge capacitor technology although close pulsestackingin devices ‘A’ and ‘O’ effectively achieved the same pulse shape
and device ‘D’ showed a nearly square pulse shape.
Measurement of UV Content
Shorter wavelengths in the ultraviolet region of the spectrum may burn the patient’s
skin or may be hazardous to the operator’s eyes and are therefore removed. Of the
30 applicators tested, 6 IPLs measured more than 1% and two measured more
than 2% of unwanted UV output below 400 nm when cut-off filters were set
significantly higher.
Comparing Average Spectral Output
The spectrum analysis of light emitted from flashlamps contains both discrete line structure
and continuum radiation. The continuum radiation is blackbody radiation, characteristic of the
temperature of the plasma in the discharge. Of 29 applicators 19 (65.5%) with cut-off filters
that were inaccurate by more than 20 nm versus the claimed cut-off value given by the
manufacturer. Only 10 applicators (34.5%) were within 20 nm of the stated cut-off.
Comparing Time-Resolved Spectral
Output
Schematic illustration of the difference in the spatial and temporal
characteristics of a free discharge and partial discharge pulse to an IPL
xenon lamp.
Time-resolved spectrum sampled every 1 ms using an OceanOptics
HR2000+ spectrometer and SpectraSuite software to demonstrate the
stability and efficiency of spectral output for free-discharge (IPL ‘C’) vs.
square pulse systems (IPL ‘E’)
IPL ‘C’—Free Discharge
IPL ‘E’—Square Pulse
IPL ‘D’ single pulse programs produce a decaying square pulse
IPL ‘D’ in a multi-pulse program showing more pronounced ‘free-discharge’
characteristics
IPL ‘G’ —Partial Discharge—square pulse
IPL ‘N’—Discharge (stated 35 ms pulse duration)
IPL ‘A’ —Free Discharge
Close “stacking” of sub-pulses produces a square pulse effect unless sub-pulses are spaced
too far apart when they simply perform like conventional free-discharge pulses.
IPL ‘L’ showing sub-pulses in typical ‘free discharge’ format
IPL ‘K’ showing sub-pulses in typical ‘free discharge’ format
IPL ‘C’ showing a typical ‘free discharge’ of ca 3 ms of energy
CONCLUSIONS
• Many manufacturers of IPLs make claims that are not
substantiated as measured by this study
• Manufacturers operating an ISO 9000 Q/A system (Medical
CE-mark) showed greater consistency of stated and actual
values for fluence, pulse duration and spectral cut-off filter
accuracy over the stated lifetime of the applicator / lamps.
• Partial Discharge (‘square pulse’) Systems
Produce the lowest possible intensity for a given fluence thus
minimising discomfort and other side effects such as skin burns (i.e.
safer to use)
• Free Discharge (‘rising/falling slope’) Systems
Produce high energy in short pulse durations with spectral shift and wasted
energy
CONCLUSIONS
• A time-resolved ‘Spectral Footprint’ as shown in
these measurements is helpful in determining the
true pulse
duration and spectral pattern of useful energy for
optimized clinical efficiency
• This first serious attempt to measure IPL
performance characteristics provides criteria that
should be carried to national representatives of the
competent regulatory body (IEC) to promote an
international standard for measuring intense light
devices
Acknowledgements
The authors wish to thank the following companies for their contribution in
reviewing the fluence test methodology used in this study:
Cyden Ltd., Swansea, Wales, UK
(www.cyden.co.uk)
Energist Ltd., Swansea, Wales, UK
(www.energist-international.com)
Instinctive Technologies Ltd., Bedford, UK
(www.instinctiveuk.com)
Lynton Lasers Ltd., Cheshire, UK
(www.lynton.co.uk)