All solid state lasers for photodynamic therapy of the malignant neoplasms

The work demonstrate possibility of the treatment of animals with malignant neoplasms using 608 nm laser radiation by means photodynamic therapy (PDT). The intracavity transformation of the Nd:YAP main radiation 1079 nm was Raman converted in barium nitrate crystal and Stokes frequency (1216 nm) was doubled using KTP or RTP crystals. The LiF or Cr:YAG crystals are used for the Q-switch. The radiation parameters were obtained at a pump repetition frequency 100 Hz. The average power at 608 nm radiation with LiF and KTP was 700 mW at multimode generation. The 3-6 single 10-15 ns pulses was generated during one cycle of pumping. The doubling efficiency with RTP was two times more than with KTP. The cells of Ehrlich adenocarcinoma (0.1 ml) were implanted in hind thighs of ICR white non-imbred mice. Photosensitizer HPD was i.v. administered in a dose of 10 mg/kg. Ten animals were treated (2 as a control). There was 9-30% decrease in the tumor growth depending on the irradiation dose. The better result (30%) was for the 200 J/cm² dose radiation. These results show the possibility of using PDT with all solid state laser with wavelength 608 nm.