Q-Switch Ruby 694nm Laser for Tattoo Removal
The Q-switched ruby laser (694 nm) is the gold standard treatment for tattoo removal, particularly effective for blue-black and green pigments, operating on selective photothermolysis principles with pulse durations of 25-40 nanoseconds. 1, 2
Technical Specifications
Optimal laser parameters for the Q-switched ruby laser include:
- Wavelength: 694 nm 1, 3
- Pulse duration: 25-40 nanoseconds (NOT microseconds—microsecond pulses are used for retinal therapy, not tattoo removal) 1, 3
- Power density: 1200-2800 GW/m² 4
- Spot size and frequency: Variable based on treatment area 3
The mechanism involves extremely rapid heating that fragments tattoo pigment particles without damaging surrounding tissue through selective photothermolysis. 2, 5
Treatment Protocol
Mandatory treatment intervals:
- Minimum 4 weeks between sessions to allow phagocytosis and clearance of fragmented pigment particles 2, 6
- Free pigment becomes intracellular again within 4 weeks, necessitating this waiting period 2
- Longer intervals may reduce risk of permanent pigmentary changes 2
Immediate post-treatment appearance: The epidermis appears white immediately after laser pulse due to water vaporization in the skin, with opaque intradermal vacuoles corresponding to vaporization of tissue water surrounding pigment suspensions. 2, 4
Expected number of sessions: Multiple treatments are required, with amateur tattoos requiring fewer sessions than professional multicolored tattoos. One documented case required 47 sessions for large multicolored tattoos. 2, 6, 5
Pigment-Specific Efficacy
The Q-switched ruby laser demonstrates superior effectiveness for:
- Blue-black pigments: Excellent response (>75% ink removal in 77% of cases) 7, 8
- Green pigments: Highly effective 1, 7
- Other colors: Less efficient removal 7, 4
For multicolored tattoos, combination therapy with other Q-switched lasers (alexandrite 755 nm for black/blue/green, Nd:YAG 532 nm for red, Nd:YAG 1064 nm for black/blue) may be necessary since no single laser system can remove all available inks. 6, 5
Patient Selection Using Kirby-Desai Score
The Kirby-Desai score estimates the number of sessions needed based on:
- Skin type (Fitzpatrick classification) 1, 2
- Tattoo colors and complexity 1, 2
- Tattoo location and age 5
Complications and Safety Considerations
Common adverse effects with the Q-switched ruby laser:
- Transient hypopigmentation: Up to 50% of patients 5
- Textural changes: Up to 12% of patients 5
- Transient hyperpigmentation: Common but temporary 3
- Scarring: Rare when proper technique is used 5, 3
Critical safety warning: Proper training in Q-switched laser use is essential, as significant burns can occur within tattoos after improper treatment, leading to scarring and poor outcomes. 2, 6
Toxicologic considerations: Cleavage products formed during laser-assisted removal pose potential risks, and tattoo particles can be found in regional lymph nodes following treatment. 2, 6
Pain Management
Treatment with Q-switched lasers is painful and requires anesthesia:
- Local injection with lidocaine 5
- Topical anesthetic cream prior to treatment 5
- Topical broad-spectrum antibacterial ointment applied immediately following procedure 5
Patient Counseling Requirements
Patients must be informed that:
- Cost: $49-$300 per square inch per treatment 1, 2
- Time commitment: Multiple sessions over months to years 2
- Incomplete clearance: Removal may be only partially effective in many cases 2
- Scarring risk: Patients with history of keloid formation should be advised of potential scarring 2
Contraindications to consider: Patients with keloid-forming tendency require careful risk-benefit assessment. 2
Expected Outcomes
Histopathologic findings demonstrate: Persistence of tattoo ink in clinically clear areas, confirming that complete microscopic clearance may not occur even when clinical appearance suggests complete removal. 8
Best results: Amateur blue-black tattoos achieve optimal scar-free cosmesis, representing a considerable improvement over non-specific laser techniques. 4