Possibilities of Laser Spectroscopy Methods for Prediction of the Radiotherapy Results

In this paper, possibilities of laser fluorescence spectroscopy to predict the reactions of the oral cavity cancer to radiation treatment are considered. A theoretically substantiated assumption about the link between the tumor’s consumption of an exogenous photosensitizer and its radioresistance is proposed. The first experience with the use of the Radahlorin photosensitizer is described; preliminary results of the 5 patients study are presented. As a result different photosensitizer consumptions versus different treatment outcomes are discussed. Keywords: laser fluorescence spectroscopy, photosensitizer, oral cavity cancer, radiotherapy, cross-resistanc

Linear theory of nonlocal transport in a magnetized plasma

A system of nonlocal electron-transport equations for small perturbations in a magnetized plasma is derived using the systematic closure procedure of V. Yu. Bychenkov et al., Phys. Rev. Lett. 75, 4405 (1995). Solution to the linearized kinetic equation with a Landau collision operator is obtained in the diffusive approximation. The Fourier components of the longitudinal, oblique, and transversal electron fluxes are found in an explicit form for quasistatic conditions in terms of the generalized forces: the gradients of density and temperature, and the electric field. The full set of nonlocal transport coefficients is given and discussed. Nonlocality of transport enhances electron fluxes across magnetic field above the values given by strongly collisional local theory. Dispersion and damping of magnetohydrodynamic waves in weakly collisional plasmas is discussed. Nonlocal transport theory is applied to the problem of temperature relaxation across the magnetic field in a laser hot spot.Comment: 27 pages, 13 figure

Laser-triggered ion acceleration and table top isotope production

We have observed deuterons accelerated to energies of about 2 MeV in the interaction of relativistically intense 10 TW, 400 fs laser pulse with a thin layer of deuterated polystyrene deposited on Mylar film. These high-energy deuterons were directed to the boron sample, where they produced ∼ 105∼105 atoms of positron active isotope 11C11C from the reaction 10B(d,n)11C.10B(d,n)11C. The activation results suggest that deuterons were accelerated from the front surface of the target. © 2001 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70713/2/APPLAB-78-5-595-1.pd

Enhanced inverse bremsstrahlung heating rates in a strong laser field

Test particle studies of electron scattering on ions, in an oscillatory electromagnetic field have shown that standard theoretical assumptions of small angle collisions and phase independent orbits are incorrect for electron trajectories with drift velocities smaller than quiver velocity amplitude. This leads to significant enhancement of the electron energy gain and the inverse bremsstrahlung heating rate in strong laser fields. Nonlinear processes such as Coulomb focusing and correlated collisions of electrons being brought back to the same ion by the oscillatory field are responsible for large angle, head-on scattering processes. The statistical importance of these trajectories has been examined for mono-energetic beam-like, Maxwellian and highly anisotropic electron distribution functions. A new scaling of the inverse bremsstrahlung heating rate with drift velocity and laser intensity is discussed.Comment: 12 pages, 12 figure

The effect of ventilator-associated pneumonia (VAP) on the risk of death in patients with major burns

The purpose of the study is to analyze the effect of VAP on the risk of death in patients with burn injury.Цель исследования – проанализировать влияние ВАП на риск летального исхода у пациентов с ожоговой травмой

On the design of experiments for the study of relativistic nonlinear optics in the limit of single-cycle pulse duration and single-wavelength spot size

We propose a set of experiments with the aim of studying for the first time relativistic nonlinear optics in the fundamental limits of single-cycle pulse duration and single-wavelength spot size. The laser system that makes this work possible is now operating at the Center for Ultrafast Optical Science at the University of Michigan. Its high repetition rate (1 kHz) will make it possible to perform a detailed investigation of relativistic effects in this novel regime. This study has the potential to make the field of relativistic optics accessible to a wider community and to open the door for real-world applications of relativistic optics, such as electron/ion acceleration and neutron and positron production.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45803/1/11452_2005_Article_253.pd

EVALUATION OF THE CLINICAL USE OF HYPOXIC CELL SENSITIZERS IN RADIATION THERAPY OF MALIGNANT EPITHELIAL SKIN TUMORS

Aim: To increase the efficacy of radiation therapy of malignant epithelial cell skin neoplasms with the use of radiation sensitizers of hypoxic tumor cells.Materials and methods: The study was performed in 517 patients with basal cell (n = 361) and squamous cell (n = 156) skin cancer, 274 (53%) of whom had T2 and 243 (47%), T3 tumors. Patients with locally advanced and metastatic tumors were excluded from the study. The following treatment modalities were used: distant gamma-therapy, short-distance radiation therapy and combined radiation therapy with the use of non-conventional dose fractioning at total local doses equal to 72–73 Gr. The sensibilization of hypoxic tumor cells to radiation therapy with metronidazole was done by targeted delivery of the drug to the tumor by means of topical application of Coletex-M drapes impregnated with metronidazole in a high concentration (up to 20 mcg/cm²). The second method of radiosensibilization of hypoxic tumor cells was based on a preliminary use of low intensity laser radiation onto the tumor. As a source this radiation, a helium neon laser was used with the power of up to 12 mVt and the wave length of 0.63 to 0.89 mcm, duration of sessions from 3 to 15 minutes. The control group comprised 192 skin cancer patients who underwent radiation therapy without the use of radiation sensitizers. Results: The use of metronidazole and low intensity laser radiation within the radiation therapy of T3 skin cancer patients, compared to the treatment without the radiation modifiers, significantly improved the immediate cure rates (full tumor regression at 1 to 1.5 months after completion of radiation) from 75.5 ± 3.1% to 89.2 ± 1.9% (р < 0.05). In the group with basal cell skin cancer that underwent radiation therapy combined with metronidazole, there was an association of its radio-modifying effect and tumor size. Short-distance roentgenotherapy of patients with T2 basal cell skin cancer and tumor size of < 4 cm was equally effective, irrespective of the use of metronidazole: the immediate cure rate was 94.8 ± 2.2% (92/97 patients) in the metronidazole group and 89.8 ± 3.9% (53/59) in the control group. With the combined radiation therapy of T2 basal skin cancer patients with the tumor size of 4–5 cm, the immediate cure rate was increased significantly from 73.2 ± 6.9% (30/42) in the control group to 88.2 ± 3.7% in the metronidazole group (67/76) (р < 0.05). With distant gamma-therapy of T3 basal cell skin cancer, this parameter was increased from 70.5 ± 6.8% (31/44) in the control group to 88.4 ± 4.8% (38/43) in the metronidazole group (р < 0.05). The radiation-sensitizing effect of metronidazole and low intensity laser combined with the distant gamma-therapy of T3 basal cell skin cancer was significant and similar: the immediate cure rate with the use of metronidazole was 85.9 ± 4.6% (49/57), and with the use of low intensity laser, 84.6 ± 5.0% (44/52), compared to 66.0 ± 6.9% (31/47) in the control group (р < 0.05).Although the relapse rate after radiation therapy with metronidazole or low intensity laser was lower by 5–11%, compared to that after the radiation without modifiers, there was no statistically significant difference after a 3-year follow-up.Conclusion: A significant benefit of radiation therapy combined with radiation sensitizers on the immediate cure rate of locally-advanced basal cell skin cancers was confirmed. It seems that radiation sensitizers of hypoxic cells do improve immediate results of cure without any significant effect on tumor relapse rate in the future

ТЕХНОЛОГІЯ РОЗРОБЛЕННЯ ЗНАННЯОРІЄНТОВАНИХ СИСТЕМ ПІДТРИМКИ РІШЕНЬ В УМОВАХ РИЗИКІВ ТА НЕВИЗНАЧЕНОСТЕЙ (ЕТАП “ОБРОБЛЕННЯ ПОЧАТКОВИХ ДАНИХ”).

The knowledge decisions acceptance support system (KDASS) in the risks and ambiguities conditions were offered. The first stage sequence of KDASS forming – the basic data processing stage was written. The first stage sequence of KDASS it was rotined on an example KDASS of achievement degree evaluation of certain possibilities of Ukraine Military Forses depending on the financing level.В статье предложена последовательность формирования знаниеориентированных систем поддержки принятия решений в условиях рисков и неопределенностей (ЗСПР). Расписана последовательность проведения первого этапа формирования ЗСПР – этап обработки исходных данных на примере ЗСПР оценивания степени достижения определенных возможностей Вооруженных Сил Украины в зависимости от уровня их финансирования.У статті запропоновано послідовність формування знанняорієнтованих систем підтримки прийняття рішень в умовах ризиків і невизначеностей (ЗСПР). Розписана послідовність проведення першого етапу формування ЗСПР - етап обробки вихідних даних наприкладі ЗСПР оцінювання ступеня досягнення визначених можливостей Збройних Сил України залежно від рівня їх фінансування

Combination treatment of parotid salivary gland cancer

Background: Cancer of the parotid salivary gland (PSG) accounts for more than a half of all cases of salivary gland malignancies. Its treatment strategy remains a matter of debate.Aim: To identify factors significantly associated with the 3-year survival of patients with PSG cancer after combination treatment.Materials and methods: Thirty nine patients with morphologically confirmed PSG cancer (T1-4N0) were recruited into the study. Surgery (partial or total parotidectomy without the cervical lymphatic node dissection) was performed in 32 patients. The most frequent diagnosis (n = 10; 25.6% of all cases) was adenocarcinoma. Radiation to PSG and the regional lymphatic nodes was used in 15 patients as neoadjuvant and in 24 as adjuvant regimen. Three-year survival rates were analyzed in 36 patients by the Kaplan-Meier method, with consideration of their sex, age and the sequence of surgical and radiation treatment.Results: The 3-year survival after combination treatment of PSG cancer patients was 82.7%. Women, patients above 60 years of age and those who received adjuvant radiation therapy demonstrated a trend towards better 3-year survival, although it was non-significant (p > 0.05).Conclusion: Combination strategy remains an effective approach to PSG cancer irrespective of age and sex of patients. The use of radiation therapy as a single modality is possible only in exceptional cases