The fundamental limitation of multi-pass laser tattoo removal in a single session is the immediate whitening — called frosting — that occurs when laser energy creates microbubbles in the dermis. These bubbles scatter subsequent laser pulses, reducing their effectiveness and requiring practitioners to wait approximately 20 minutes for the frosting to resolve before the next pass (the R20 method). Perfluorodecalin (PFD) patches eliminate this waiting period by optically clearing the frosting in real time, enabling multiple passes within minutes rather than hours.
How PFD Patches Work
Perfluorodecalin is a clear fluorocarbon liquid with a refractive index close to that of skin tissue. When applied to the skin surface in a soft silicone patch format, it optically couples with the skin, reducing the air-skin interface reflections and effectively making the gas microbubbles (frosting) less optically obstructive. Laser energy transmits through the PFD-coupled skin surface and the frosted zone more effectively than through air-coupled skin, allowing the next pass to work on the tissue beneath the frosting almost immediately after the previous pass.
In practice, this means a practitioner can perform 3 to 4 laser passes in a single session with only 1 to 5 minutes between passes rather than 20 minutes, compressing the treatment timeline significantly and enabling the DESCRIBE protocol — a specific multi-pass treatment approach built around PFD patch use.
The DESCRIBE Protocol
DESCRIBE (Defocus Erythema and Surface Cooling with Repeated Impulse Bursts Enhanced) is the formal treatment protocol developed around PFD patch use. In the DESCRIBE protocol, the practitioner performs the first pass with standard parameters, applies the PFD patch, then performs additional passes through the patch at adjusted fluence, taking advantage of the optical clearing to reach the dermis more effectively.
Published studies on the DESCRIBE protocol have shown superior clearance rates compared to standard single-pass treatment, with clearance results similar to R20 but achieved in a significantly shorter session time. The protocol has received FDA clearance as an adjunctive device for laser tattoo removal.
Practical Limitations
PFD patches add cost to each treatment session — the patches are single-use and represent a consumable expense on top of the device operational cost. Not all clinics stock them, and some practitioners who use R20 with standard 20-minute intervals do not see sufficient benefit to justify the added cost. The patches also require a specific technique of laser delivery through the patch that requires practice to execute consistently.
For patients interested in this option, the key questions to ask are whether the clinic uses PFD patches and for what types of cases, and how the per-session cost with PFD patches compares to standard multi-pass pricing.