Multiple clinical studies have shown that interstitial photodynamic therapy (I-PDT) is a promising modality in the treatment of locally-advanced cancerous tumors. However, the utilization of I-PDT has been limited to several centers. The objective of this focused review is to highlight the different approaches employed to administer I-PDT with photosensitizers that are either approved or in clinical studies for the treatment of prostate cancer, pancreatic cancer, head and neck cancer, and brain cancer. Our review suggests that I-PDT is a promising treatment in patients with large-volume or thick tumors. Image-based treatment planning and real-time dosimetry are required to optimize and further advance the utilization of I-PDT. In addition, pre- and post-imaging using computed tomography (CT) with contrast may be utilized to assess the response.
It is shown that if one has access to only one mode of a two-mode squeezed-vacuum state, the photon statistics of this mode is indistinguishable from that of a thermal distribution. Parametric interactions that give rise to two-mode squeezing thus provide a mechanism for thermalization that is intrinsically quantum mechanical. Two-mode squeezed-coherent states have received considerable theoretical attention' and have recently been generated experimentally via four-wave mixers and parametric down converters.In such parametric processes photons are generated in pairs with one photon at frequency coo+co and the other at cooco where coo is a carrier frequency which is half the pump frequency for a parametric down converter or equal to the pump frequency for four-wave mixers. We will arbitrarily call the mode at frequency coo+co the signal and the mode at othe idler. The signal and idler modes can be spatially separate as in the case of the photon-correlation experiments of Friberg, Hong, and Mandel. ' For squeezed-state experiments the optics is genera11y arranged so that the signal and idler beams are collinear.Since the signal and idler modes have different frequencies they can be spatially separated with a dispersive element even if generated collinearly. Hence one can have access to the signal mode or idler mode separately. Here it is shown that the light in the signal mode or the idler mode is indistinguishable from thermal light when the incoming light is in the vacuum state. This is remarkable since the squeezing Hamiltonian which transforms the vacuum state into a two-mode squeezed state does not give rise to classical chaotic behavior and the twomode squeezed state itself is a pure quantum state. This pure state has two parts, the signal and idler which when viewed separately have photon statistics that are indistinguishable from thermal light. Four-wave mixing or parametric down conversion is a process by which an intense pump beam modulates the susceptibility of a nonlinear medium on the time scale of an optical cycle. The time-dependent susceptibility does parametric work on the vacuum to create photon pairs. Equivalently one can regard the pump as modulating the index of refraction or the optical path length of the medium.In fact, parametric photon pair production could in principle be achieved by wiggling one of the mirrors of an empty optical cavity' at twice the cavity's resonant frequency. Hence the mechanism by which a parametric process generates thermal noise from the vacuum can be regarded as being similar to the mechanism by which a mirror undergoing constant acceleration generates thermal noise from the vacuum. This latter system has played a significant role in the discus-sion of black-hole evaporation. " The calculations here are carried out in the Schrodinger picture. Let a & and a2 denote the usual boson annihilation operators for the signal and idler mode, respectively, i.e. , [a;,]2) ] =5;ã nd [a;,a, ]=0 for i, jH I 1,2I. For later use in determining the classical correspondence it is ...
Exponential decay and blow up of a solution for a system of nonlinear higher-order wave equations AIP Conf. Proc. 1470, 118 (2012); 10.1063/1.4747654Landau-Lifshitz and higherorder nonlinear systems gauge generated from nonlinear Schrödingertype equations A set of coupled higher-order nonlinear Schrodinger equations, which describe electromagnetic pulse propagation in coupled optical waveguides, is formulated in terms of an eigenvalue problem. Using that result, the inverse scattering problem is solved and explicit soliton solutions are found. Additionally, linear coupling terms are studied systematically.1208
The modulation instability of an extended nonlinear Schrödinger equation was investigated. It was found that the odd-order higher dispersion [beta(3)] does not contribute to the modulation-instability frequency. The time derivative of the nonlinearity was included and shown to affect the instability. Finally, nonlinear retardation effects are shown to alter the results significantly.
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