Clinical Study

F1 diode laser™ twelve-month clinical study

Daniel Barolet md, Dermatologist, University of Montreal, Montreal, Canada

 
        

The purpose of the study was to evaluate two configurations of the F1 Pulsed Diode Laser System for Hair Removal. One configuration consisted of a pulsed diode laser emitting at 810nm. The second configuration consisted of a pulsed diode laser emitting at 980nm.
The study was conducted from April 1999 to March 2000. IRB Services (FDA approved independent ethical review committee) reviewed the ethical aspects of the study.
Results from the study were presented at the ASLMS (American Society for Laser in Medicine and Surgery) meeting in Reno, Nevada in April, 2000 by Dr. Barolet (Barolet D. Comparison of two infrared laser systems for hair removal, Lasers Surg Med., Supp. 12, 2000, p.20).

I. Protocol

A total of seventeen (17) patients were recruited into the study. The seventeen patients were accepted with the following criteria:

Inclusion Criteria:

  1. Subject were either gender.
  2. Subjects were between 18 and 70 years of age and had unwanted hair.
  3. Subjects were willing to abstain from use of any additional hair removal treatment during the duration of the study.
  4. Subjects were willing and able to comply with all follow-up requirements

Exclusion Criteria:

  1. Active localized or systemic infections.
  2. History of acne scarring or HSV in the treatment area.
  3. Photosensitivity or allergy.
  4. Hair removal treatment for 6 weeks prior to the start of the study.
  5. Patients under 18 years of age.
  6. Taking of drugs, especially: Androgens, Cortisone (Prednisone), Cyclosporin A, Diazoxide, Dilantin, Minoxidil, Penicillamine, Psoralen, Streptomycin. In addition, during the 12 months preceding the study, patients are required not to take Accutane (isotretinoin).
  7. Blond or white hair (hair in the site of treatment must be brown or black).
  8. Excessive tan at the site of treatment.
  9. Previous laser hair removal at the treatment site (to be studied).Known diseases A. Skin: vitiligo, psoriasis, severe eczema, poor skin healing (keloid) B. Chronic or acute: active infection, immunosuppression, coagulation problem.
  10. Pregnancy.
  11. Alcohol or drug abuse before and during the study.
  12. Any participation in another study during the 4 weeks preceding this study.
  13. Underlying hormonal problem not controlled (not stabilized) by an endocrinologist.

Informed consent was obtained from all subjects after objectives, design and risks of the study were explained. Patient pretreatment evaluations included medical evaluation, review of enrolment criteria, and determination of skin type (Fitzpatrick scale I-VI).
Large test sites on the back or thighs of N=17 patients with skin type I-V (fair to dark-skinned) and any hair color, were shaved and treated with 15-25 joules / cm2 fluence (15,20,25), using two different diode lasers: 810 nm and 980 nm. Baseline and subsequent regrowing terminal hair characteristics were obtained from each site by digital imaging and sophisticated software analysis for hair count and hair diameter. One adjacent control (shaved) site was also analyzed. Test sites were on the back or posterior aspect of the thighs based on uniformity, density and hair growth cycle (5-8 months) of terminal hairs. Twenty-five 2 X 3-cm areas were mapped (‘medical tattoos’) and photographed. Hair characteristics were obtained over 12 months. Before laser exposure every test sites were shaved. Half of the sites were irradiated with a 810 nm diode laser and the other half with a 980 nm diode laser with one shaved control site. Laser pulses were given in a contiguous, non-overlapping pattern that covered the entire test site.
Treatment was also given to any body site elected by the patient.
No pre-treatment regimen was required for this study.
Hairs at each site were trimmed to a uniform length of 2-3mm using a safety razor.
A digital image of each treatment site was taken at the initial visit. A CCD video camera was used to project the image of the treatment site onto a computer screen providing high resolution hair imaging. The number of hairs were counted by software designed for hair count and hair diameter. The hair was counted using the same method at subsequent follow up visits.
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The following table represents the protocol for the treatment regime on each patient. All treatments were delivered to each patient with the same protocol. Sites receiving multiple treatments were treated at one month intervals
Table 1

# of Sites Wavelength Fluence # of Treatments
1 Control Control Control
3 810nm 15,20,25 J/cm2 1
3 980nm 15,20,25 J/cm2 1
3 810nm 15,20,25 J/cm2 2
3 980nm 15,20,25 J/cm2 2
3 810nm 15,20,25 J/cm2 3
3 980nm 15,20,25 J/cm2 3
3 810nm 15,20,25 J/cm2 4
3 980nm 15,20,25 J/cm2 4

Patient treatment and follow-up visits:

  1. Pre-treatment evaluation visit
  2. Initial treatment visit
  3. 2nd treatment visit (one month post initial)
  4. 3rd treatment visit (two month post initial)
  5. 4th treatment visit (three month post initial)
  6. 5th visit — observation
  7. 6th visit — observation
  8. 7th visit — observation
  9. 8th visit — observation with photographs and hair count
  10. 9th visit — observation with photographs and hair count
  11. 10th visit — observation with photographs and hair count
  12. 11th visit — observation with photographs and hair count
  13. 12th visit — observation with photographs and hair count
Patient Risks:
Risks to the Subjects who participated in this study were the same as those for Subjects undergoing any dermatological laser treatment, such as for the removal of pigmented or vascular lesions. Risk were explained to the subjects and were identified as follows: blistering, edema, erythema, and mild to moderate local pain. A lesser possibility existed for dyspigmentation, scarring, and/or infection.

STUDY DESIGN
Subjects were entered into the study as they presented themselves for treatment to the investigator if and only if they met the inclusion and exclusion criteria noted in the previous section.

II. Results

Results of this study showed significant improvement in the amount of unwanted hair.
For both wavelengths (810 & 980nm), all subjects were responders and regrowing hairs were thinner and lighter. However with the highest fluence (25 J/ cm2), the response (maintained at 7 months) was significantly higher at 810 nm with 36 % hair loss after 1 treatment, 32 % hair loss after 2 treatments, 39 % hair loss after 3 treatments and 52% hair loss after 4 treatments (shaved control 4%).

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Adverse Events
Some partial and temporary reddening of the treated area was seen.
Transient pigmentary changes were observed. There were no incidents of scarring.

III. Conclusion

These results show that diode lasers can affect either structural recovery (size of hair) and follicular pigmentation (hair absorption coefficient) even with low fluence energy (up to 25 J/cm2). The response is wavelength-dependent with a cumulative effect after multiple treatments especially at 810nm.
Permanent hair reduction (after a complete hair cycle for back and thigh : 7 months) has been shown in this study especially at 810nm (F1 diode laser system).
Published data concerning hair removal using a pulsed diode laser1 indicates success rates similar to those obtained using the F1 diode laser™ system that was used in this study. Published success rates indicate that hair reduction after 2 treatments, measured at 9 months post-treatment are 15.5% - 41.4 %. The success rate for the F1 diode laser system, measured 9 months post treatment range from 32% after 2 treatments to 52% after 4 treatments.
All in all, the F1 diode laser™ system for hair removal is as successful as currently marketed devices even at relatively low fluence (25J/cm2).

1 Dierickx, C. Anderson, R. Campos, A. Grossman, M. : Effective, Permanent Hair Reduction Using a Pulsed, High-Power Diode Laser. Coherent WebPages, December, 2000.


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