Faculty Summaries
Eugene Fourkal
Eugene Fourkal, PhD
Associate Professor
Office Phone: 215-214-1712
Fax: 215-728-4789
Office: P0083
  • 1. Laser-driven proton source for radiation therapy applications

    My research activities in the past 10 years centered on the topic of production of proton and heavy ion beams using high-power lasers for radiation therapy applications. The emerging technology of laser-particle acceleration opens up a possibility for designing a proton therapy system that may significantly improve the patient care throughout the world. One of the goals of the project is to find the most optimal interaction parameters that would lead to production of ion beams in the therapeutic energy range. Through a series of research endeavors, we were able to ascertain the exact set of laser/target parameters that are favorable in the production of desired quality proton beams. In addition, a novel idea of multi-stage acceleration of proton beams was recently introduced by our group that promises high energy transfer efficiency between the laser light and protons. A recent experimental investigation by a group from Germany confirmed our theoretical predictions with a two-stage laser-acceleration scheme.

    Another goal of this project involves the hypothesis that the laser-driven proton bunches may have higher cell killing power due to their bunching effect, in which the protons come as a single cluster of several picoseconds duration and under certain conditions that are currently being investigated, a higher biological effectiveness of a proton cluster may ensue.

  • 2. Absolute dose reconstruction in hadron therapy using PET imaging modality

    Positron emitters are activated by proton beams during the course of hadron therapy. These short-lived radioisotopes, mainly 11C, 13N and 15O, allow the imaging of three-dimensional in vivo activity distribution using positron emission tomography, which can be ultimately implemented into quality assurance and treatment verification after proton therapy. The proposed PET imaging for treatment verification however, only exploits the possibility of using information contained in the spatial activity distribution to verify the field positioning and to gain insight into the beam penetration depth. The natural extension of these ideas would be to use the three dimensional activity to reconstruct the dose delivered to a patient. Since there is no direct correlation between the absorbed dose and activity (which is intrinsically due to the difference in the underlying physics behind the energy deposition process in a case of absorbed dose and nuclear processes involved in the positron activation in the case of induced activity), one cannot readily obtain one from the other once the treatment has been completed. Even though the indirect method is appealing and relatively easy to develop, it does not provide direct comparison between the planned and delivered doses, thus always bringing some uncertain (or unsatisfactory) aspect associated with it. This is why the development of the dose reconstruction method from the information stored in the spatial activity distribution presents a more desirable solution. In a recent investigation, we used an analytical approach to see if it would be possible to reconstruct the dose absorbed in a patient from the activity distribution. It is based on the solution of the inverse problem of activity de-convolution with the introduced positron emitters’ species matrix or PESM. We showed that it is possible to reconstruct absolute dose from the information stored in the spatial activity distribution. In our future investigations we are planning to use the neural networks approach to solve the inverse problem for cases with many degrees of freedom encountered in spot scanning proton treatments.   

  • 3. Super-lensing technology for biological imaging

    Recent developments in a field of nanophotonics and metamaterials opens up a way for the development of the so-called super-lens, a lens that can be used in imaging objects beyond the diffraction limit. This limit is universal and is due to the loss of fine-structure information about the imaged object. A metamaterials-based superlens offers a possibility of recovering the lost information, so that an object can be imaged with the light’s wavelength many times longer than the object’s dimensions. This may eventually offer a non-invasive method of imaging the fine details of cells with visible light, which is not possible with regular microscopes. In our recent work we looked at the fundamental aspects of information transmission and recording by the super-lens. The results of this project reveal that the recording device is an integral part of the imaging system and what the observer sees during the act of observation depends on the recording device’s physical characteristics.

  • 4. Photo-thermal cancer therapy using Gold nanoparticles

    The existence of surface plasmon resonance of noble metal nanoparticles at optical frequencies makes them exceptional absorbers and scatterers of photons in a wide energy range. This fact, in conjunction with recent developments in nanoparticle synthesis and conjugation has paved the way for their possible utilization in biomedical applications. The surface plasma resonance dramatically increases the energy conversion efficiency between the external laser source and the nanoparticle, which in turn leads to very efficient heat generation and temperature increase in the space around the nanoparticle. It also allows for very specific geometric targeting of the heating dose, since only the area where the nanoparticle are present will experience dramatic heat deposition, whereas the area where the nanoparticles are absent will not be the subject to the heat treatment, even in the presence of a powerful laser source. In recent in-vitro studies we looked at the efficiency of the gold nanorods to induce thermal necrosis in A-1 ovarian cancer cells when exposed to infrared laser light. It was found that gold nanorods are extremely efficient agents in inducing cell necrosis, provided that proper nanoparticle concentrations are attained.