Evgueni Parilov

• PhD
• Chief Technology Officer at Simphotek Inc

Photodynamic Therapy: Killing cancer gently with visible light Drs. Mary Potasek, Evgueni Parilov, and Karl Beeson, who are all co-founders of Simphotek, Inc have been using a novel therapeutic modality known as Photodynamic Therapy (PDT) to treat cancer, with far fewer side effects than traditional radiation x-ray methods. By using near-infrared o...

Simple Summary There are no effective treatments for patients with cancers that induce airway narrowing via extrinsic pressure to the bronchus (i.e., extrinsic malignant central airway obstruction—MCAO). The effects of these cancerous tumors must be quickly alleviated to allow normal breathing and delay disease progression. Currently, stents are us...

We developed a simulation method for modeling the light fluence delivery in intracavity Photodynamic Therapy (icav-PDT) for pleural lung cancer using a moving light source. Due to the large surface area of the pleural lung cavity, the light source needs to be moved to deliver a uniform dose around the entire cavity. While multiple fixed detectors a...

Photodynamic therapy (PDT) has been used intraoperatively to treat patients with malignant pleural mesothelioma. For the efficiency of PDT, it is crucial to deliver light doses uniformly. The current procedure utilizes eight light detectors placed inside the pleural cavity to monitor the light. An updated navigation system, combined with a novel sc...

Cancer therapy using Photodynamic Therapy (PDT) has been investigated for some time [1,2] and now it is a growing area of interest in clinical trials [3]. Monte Carlo (MC) simulations were used for early laboratory studies [4,5] for analysis in PDT. Various improvements in the MC method have advanced the field in recent years.

We compare previously reported benzoporphyrin derivative (BPD)-mediated photodynamic therapy (PDT) results for reactive singlet oxygen concentration (also called singlet oxygen dose) on mice with simulations using a computational device, Dosie™, that calculates light transport and photokinetics for PDT in near real-time. The two sets of results are...

Accurate light dosimery is critical to ensure consistent outcome for pleural photodynamic therapy (pPDT). Ellipsoid shaped cavities with different sizes surrounded by turbid medium are used to simulate the intracavity lung geometry. An isotropic light source is introduced and surrounded by turbid media. Direct measurements of light fluence rate wer...

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 phot...

Using a novel numerical method we show how to optimize the resolution enhancement of stimulated emission depletion (STED) by simulating the entire process including the absorption, overlapping multiple beams and stimulated emission. We provide calculations showing that for fixed donut pulse energy, a longer donut pulse length can result in greater...

Many techniques in biological and clinical science use multiphoton absorbers for fluorescence. The applications include medical imaging for living cells, diagnostic techniques for disease and spectroscopy. The intrinsic value of the multiphoton absorber coefficients is therefore of the utmost importance. Additionally, the laser intensity at which t...

Multiple fluorescent probes (multi-dyes) and single or multi-laser configurations can significantly extend the applications and accuracy of microscopy. Multiple fluorescent probes enable the user to identify more than one target, but difficulties can arise due to overlapping spectral emissions of the different probes. In particular, spectral overla...

It is now possible to make an intelligent choice for a laser without having to obtain any lasers for on-site measurements with the help of simulation software. When looking for an alternative to a usually expensive Ti:sapphire laser, we can pre-test lasers by performing numerical calculations using the SimphoSOFT simulation platform. This software...

The present invention is a method, a system and a software arrangement that can be used to determine the interaction between electromagnetic radiation and a material. The invention simplifies the process of determining the interaction by separating the complex process into a plurality of simple transition modules. Each transition module is associat...

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Traditional numerical analyses of laser beam transmission through "active" nonlinear materials have involved many assumptions that narrow their general applicability. As more complex optical phenomena are widely employed in research and industry, it is necessary to expand the use of numerical simulation methods. Historically, laser-matter interacti...

Many traditional investigations of saturation in multiphoton absorbers with the z-scan method use an approximate analytical formula that assumes a steady-state approximation. Using a numerical simulation for Maxwell's equations for laser propagation including diffraction and coupled electron population dynamics, we show that the commonly used analy...

Simphotek has developed a new algorithm known as the active photonics building block (APBB) method to make calculations of photophysical interactions in materials a fast and straightforward process. The APBB method uses uniquely defined mathematical expressions to link icons on the user interface defining active photonic interactions to the main si...

Advances in biophotonic medicine require new information on photodynamic mechanisms. In photodynamic therapy (PDT), a photosensitizer (PS) is injected into the body and accumulates at higher concentrations in diseased tissue compared to normal tissue. The PS absorbs light from a light source and generates excited-state triplet states of the PS. The...

In flow cytometry a group of cells labeled with a fluorescent probe molecule or dye is focused into a single cell stream passing through a laser light source. The fluorescent light is filtered and sampled by an array of detectors. In many cases a single light source and one probe/dye molecule have been used. But additional information can be obtain...

Simphotek has developed SimphoSoft, which models light interactions with active materials directly from the user interface. The basic concept reduces the billions of possible photoactivated phenomena to the least common denominator, Simphotek's Transition Modules (TM). The mathematical method links these TMs to the underlying equations used to desc...

Detecting, modeling and rendering complex configurations of curvilinear features

We have developed a mathematical/numerical framework based on computational transition modules and measured ultrafast laser light propagating through nonlinear materials. The numerical framework can be applied to a broad set of photo-activated materials and lasers, and can optimize photo-physical parameters in multi-photon absorbers. Two photon (TP...

We describe a unique mathematical/numerical model to analyze ultrafast laser experimental data and obtain two-photon (TPA) and multi-photon (MPA) absorption parameter(s). The material used to demonstrate the numerical method is a hybrid organic-inorganic nano-structured semiconductor quantum dot-polymer composite. Chemical, biological and engineeri...

We describe a general numerical method for calculating short-pulse laser propagation in rare-earth-doped materials, which are very important as gain materials for solid-state lasers, fiber lasers and optical amplifiers. The split-step, finite difference method simultaneously calculates changes in the laser pulse as it propagates through the materia...

The critical nonlinear Schrödinger equation (NLS) is the model equation for propagation of laser beam in bulk Kerr medium. One of the final stages in the derivation of NLS from the nonlinear Helmholtz equation (NLH) is to apply paraxial approximation. However, there is numerical evidence suggesting nonparaxiality prevents singularity formation in t...

We cover five general areas: (1) optical limiting (2) organic multiphoton absorber (AFX) (3) numerical methods (4) relationship between the building blocks/decay rate matrix and the coupled propagation/rate equations and (5) semiconductor quantum dots.

The standard bilinear interpolation on normal maps results in visual artifacts along sharp features, which are common for surfaces with creases, wrinkles, and dents. In many cases, spatially varying features, like the normals near discontinuity curves, are best represented as functions of the distance to the curve and the position along the curve....

We introduce a generalized numerical method to calculate short-pulsed laser propagation in a wide class of multiphoton absorbing materials. The method has no restrictions on the input pulse widths varying from nanosecond to femtosecond, and its numerical solution is both radially and temporarily dependent, enabling us to check numerically the valid...

Normal mapping uses normal perturbations stored in a texture to give objects a more geometrically complex appearance without increasing the number of geometric primitives. Standard bi- and trilinear inter- polation of normal maps works well if the normal field is continuous, but may result in visible artifacts in the areas where the field is discon...