LDF assessment of tumor blood flow and flux motions in photodynamic therapy
In patients with basal cell carcinoma (BCC) skin microcirculation was measured by the laser Doppler flowmeter (LDF). Spectral analysis of LDF-signal based on fast Fourier transform enables us to evaluate an amplitude and predominated frequency of flux motions in the next diapasons: α-rhythm (1-3 cycles/rain, or min-1), β-rhythm (4-8 min-1), γ-rhythm (9-11 min-1), high-frequency rhythm (HF 12-30 min-1) and cardiorhythm (CF - 50-90 min-1). For photodynamic therapy (PDT) hematoporphyrin derivative was administrated intravenously in dosage 1-2 mg/Kg. In 24 hours after that all patients were exposed to the red laser irradiation (0.67 μm) in dose 200-300 J/cm2. The microcirculation level in BCC was higher than in the plots of healthy skin (13.1±1.18 a.u. against 8.1±0.96 a.u. respectively, p<0.01). Exactly after PDT the marked decrease of microcirculation up to 4.7±0.63 a.u. associated with photoinduced stasis took place in the tumor. Spectral analysis of flux motions demonstrated a significant inhibition of α-, β-rhythms and amplification of HF- and CF-rhythm. In 1 week after PDT we observed a gradual restoration of microcirculation in the zone of PDT skin injury that followed a wound healing process.