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The application of quantum electronic devices like lasers and high speed MRI provide the potential for less invasive detection techniques and drastically improved treatment of cancer (Upile et al., 2011). Lasers employ the principle of stimulated photon emission to produce light that markedly differs in quality, depending on the wavelength of the radiation in ultraviolet (UV), infrared (IR) or visible regions of the spectrum (Joffee et al., 1989). In this context, laser fiber optics have been used for minimally invasive access and treatment of inoperable cerebral and head and neck neoplasms as well as tumors in other organs and systems (Feyh et al., 1996; Jager et al., 1996; Vogl et al., 2002a; Vogl et al., 2002b). For the past 50 years, several laser technologies have been employed in surgical oncology, including CO2 laser for cutting and coagulating and laser-induced thermal therapy (LITT) for thermal ablation of cancer. Photodynamic therapy (PDT) is an approach which has a wide range of application from acne to wrinkles, bactericidal cleansing, cancer treatment, etc (D'Cruz et al., 2004). In PDT, the absorption of photons by organic compounds can excite orbital electrons and increase kinetic energy levels leading to chemical reactions, but also may include light emission as fluorescence or transfer energy directly to oxygen molecules forming singlet and free radical species (Carmichael et al., 1983; Paiva et al., 1996). Anthracyline derivatives, such as adriamycin and daunomycin, are the most common anticancer agents that interact with light to elicit fluorescence, membrane photo labeling, laser activation and killing of tumor cells (Andreoni et al., 1991; Nahabedian et al., 1988; Saxton et al., 1996). Studies with these anticancer agents include reports of excited states of these drugs and further generation of radical oxygen species which appear to be wavelength dependent, from 313 to 498nm (Paiva et al., 1996). Some reports have shown that yeast cells were sensitized and killed by adriamycin after irradiation at 365nm, a wavelength that presented no effect in the absence of the drug. Also, cytotoxicity of several anthracycline derivatives are significantly enhanced by continuous wave green light of argon (514nm) or KTP (532nm) laser illumination of different types of cancer, both in vitro (Li and Chignell, 1987; Paiva et al., 1996) and in vivo.(Nahabedian et al., 1988; Peavy et al., 1992; Soudant et al., 1992; Paiva et al., 1995). |
