🩹 UVB Phototherapy Mechanism Simulator (3D)

Why 311nm Narrowband UVB

Narrowband UVB isolates the most therapeutic wavelength band. This 3D companion renders the same dose/session formulas as the 2D original inside a real skin cross-section — an orbitable epidermis-over-dermis slab instead of a flat side view.

• 311 nm: Peak wavelength (narrowband UVB (TL-01))
• 280–320nm: Broadband range (older UVB devices)
• Lower: Erythema efficiency (vs broadband UVB)
• ~70%: Clearance rate (typical psoriasis response)

Spectral targeting of the therapeutic band

311nm targets pathology while sparing surrounding tissue.

Narrowband lamps reduce burn risk versus broadband UVB.

Inducing Apoptosis in Pathogenic T-Cells

UVB photons damage DNA in activated dermal T-lymphocytes, rendered here as glowing spheres suspended through the dermis volume that dim and fade as each beam strikes nearby.

• Th1/Th17: Target cells (psoriatic T-lymphocytes)
• DNA damage: Mechanism (pyrimidine dimer formation)
• ~2–4 wks: Onset (sessions to clinical effect)
• IL-17, IL-23: Cytokine drop (reduced signaling)

Photoimmunology of T-cell depletion

Repeated exposure depletes pathogenic skin-infiltrating T-cells.

Apoptosis reduces local inflammatory cytokine load.

Restoring Normal Epidermal Turnover

Keratinocyte division slows from psoriatic to normal rate — visualized as a hexagonal lattice tiling the epidermis surface that shifts from red (hyperproliferative) to green (normalized) as T-cell suppression rises.

• ~4 days: Psoriatic turnover (vs 28 days normal skin)
• ~28 days: Target turnover (normalized epidermal cycle)
• ↓ over weeks: Plaque thickness (scale and thickness reduce)
• Cytokine drop: Driven by (from T-cell suppression)

Coupling immune signal to keratinocyte cycle

Reduced cytokines slow keratinocyte hyperproliferation.

Normalization lags behind immune suppression by design.

Titrating to the Minimal Erythema Dose

Dose is escalated just below the erythema threshold.

• Pre-treatment: MED test (individualized dose baseline)
• 10–20%: Typical increment (per session escalation)
• Minimal pink: Erythema target (sub-blistering threshold)
• I–VI scale: Skin phototype (adjusts starting dose)

Balancing efficacy against burn risk

Dose titration maximizes benefit while limiting erythema.

Overshooting MED risks burns and treatment pauses.

Cumulative Dose and Long-Term Skin Cancer Risk

Lifetime UVB exposure is tracked to manage cancer risk.

• Cumulative J/cm²: Risk factor (lifetime dose tracking)
• 20–30 sessions: Typical course (per treatment cycle)
• Annual skin exam: Monitoring (long-term surveillance)
• Lower: Risk vs PUVA (compared to psoralen UVA)

Managing lifetime phototherapy exposure

Cumulative dose logs inform long-term treatment limits.

Narrowband UVB carries lower carcinogenic risk than PUVA.