Diffusion Weighted and Dynamic Contrast Enhanced Magnetic Resonance Imaging in Carcinoma of Cervix: Role of Apparent Diffusion Coefficient Value and Time Intensity Curve Pattern in Chemoradiotherapeutic Response Evaluation

Introduction: Magnetic resonance imaging (MRI) is a widely used imaging modality in the imaging evaluation of carcinoma of cervix. The aim of our study was to evaluate the response in carcinoma cervix patients following chemoradiotherapy by Diffusion weighted (DW-MRI) and Dynamic contrast enhanced-MRI (DCE-MRI). Methods: 21 inoperable biopsy proven patients (mean age 48.43 years) of carcinoma cervix were included in the study. All patients underwent MRI (conventional, DW and DCE) of the pelvis thrice. Baseline MRI, Post chemotherapy MRI after neoadjuvant chemotherapy and Post chemoradiotherapy MRI after completion of concurrent chemoradiotherapy. Post treatment apparent diffusion coefficient(ADC) values and Time intensity curve(TIC) pattern were compared with baseline values. Results: Baseline meanADC value of all patients was 0.82 x10-3 mm2/s. After completion of treatment, 18 patients showed complete resolution of tumor and showed 0.50 x10-3 mm2/s increase in meanADC value from baseline MRI which was significantly higher than remaining 3 patients with residual tumor (0.50 x10-3 mm2/s v/s 0.17 x10-3 mm2/s). ADC threshold value of 1.15 x10-3 mm2/s was defined, differentiating the residual tumor from the healthy cervical tissue after chemoradiation. On post treatment MRI, 17 out of 18 patients with complete resolution of tumor showed increasing trend of enhancement on TIC and only one patient showed plateau pattern. 2 of the 3 patients with residual tumor showed washout pattern and one patient showed plateau pattern. Conclusion: ADC values and TIC pattern differ in patients with complete response to chemoradiotherapy from patients with residual tumor, so helps in differentiating residual tumor from cancer free cervix. Keywords: Carcinoma of cervix; Chemoradiotherapy; Diffusion weighted MRI; Dynamic contrast enhanced MRI; Time intensity curve.

Detecting Electromagnetic Geographical Environment Changes Based on the Frequency-Intensity Curve

Electromagnetic geographic environment is closely related to human life. With continuous popularization of public infrastructures and daily electronic instruments, such as electric power communication systems and household appliances, electromagnetic radiation sources have increased sharply in the geographic environment, which leads to increasingly serious electromagnetic radiation pollution. Thus, it is significant to monitor, evaluate, and analyze the electromagnetic radiation condition and explore its changing law in the environment. However, the traditional monitoring method can only detect anomalies within certain frequencies in the fixed stations. To fill this gap, this research first develops a vehicle-mounted electromagnetic environment monitoring system to collect both spatial positioning data and electromagnetic data of the whole frequency range. The acquired data are then used to construct the location-based frequency-intensity curve to reflect the variation of electromagnetic radiation at different frequency ranges. On this basis, a curve similarity measurement method is introduced to analyze the similarity of different curves, which is effective to diagnose time-varying sources from both global and local perspectives. This research provides a real-time mobile monitoring method, which is significant to know the dynamic variation of local electromagnetic environment and promotes subsequent comprehensive geographic analyses.

Implementation Of The Flat Beam Technology In Lighting devices Using A Flat Mirror Surface

The article discusses one of the ways to obtain a contrasting boundary between the illuminated and unlit areas of the object (illumination technology Flat Beam) in LED lighting systems using secondary optics in the form of a flat mirror surface. The results of studies of high-power LED light sources with different emitting surface areas and with three proposed options for fixing a flat mirror surface are presented. It is shown experimentally that the optical system for LED light sources in the form of a flat mirror surface allows changing the luminous intensity curve of LED light sources, converting it in a given plane from a cosine to a concentrated one. This is how the Flat Beam lighting technology is realized. Variants of the practical application of this lighting technology obtained by using a flat mirror surface with LEDs are also proposed.

ABOUT THE CREATION OF AN LED LIGHT SOURCE WITH VARIABLE COLOR TEMPERATURE

The article is devoted to the development and research of an LED lamp of the A65 form factor and the type of E27 base with a choice of color temperature when the lamp is alternately connected to the supply network. The description of LEDs, driver, radiator, housing, base is given. Analysis of the results of measurements of lighting characteristics showed that the luminous flux and power consumption of the LED lamp amounted to 1004.1 lm and 12.5 W at a measured color temperature of 3056 K and 1059.8 lm and 12.37 W at 4120 K. Change in the color temperature of the lamp from 3056 K to 4120 K is characterized by an increase in the spectral density in the region of short-wave radiation with an increase in the proportion of blue, blue and violet colors. The shape of the lamp luminous intensity curve is close to the diffuse distribution. The change in color temperature is carried out by turning off and then turning on the lamp in the mains for no more than 5 seconds.

A Refinement Of The Determination Method Of The Linear low-pressure Uv Lamps Radiant Flux

For the measurement of linear low-pressure UV lamps radiant flux the method proposed by the IUVA, which is based on the Keitz method, has become widely used. For deriving the equation that connects the irradiance generated by a lamp at a close distance and its radiant flux, the authors of the method presume that the lamp is the cylinder of equal radiance. According to our estimates, this assumption leads to the inaccuracy of 3 % to 5 % with respect to goniophotometric measurements. In this research, a general formula is derived that connects the irradiance generated by a linear emitter and its radiant flux. This formula does not impose restrictions on the radiant intensity curve in the longitudinal plane. The Keitz equation is its particularcase. To reduce the inaccuracy of the IUVA method, the angular distribution of the radiant intensity of the UV lamps is proposed to be approximated by a cosine polynomial. In order to find the coefficients of the polynomial,clarify the Keitz formula, as well as to estimate the inaccuracy of the refined and classical versions of this formula, the series of goniophotometric measurements of the DB15, DB18, DB30 lamps at various distances was carried out. It was found that at a scanning step Δθ = 5° the first 9 terms of the trigonometric expansion are sufficient to describe the radiant intensity curve with accuracy satisfactory for practical use. It was also shown that the Keitz method needs to be refined only on the basis of goniophotometric data obtained upon condition r / l ≥ 6 where r is the test distance, l is the lamp length. It was identified that in the case of a differentiated approach, the approximation of the low-pressure UV lamps radiant intensity curve by a cosine polynomial makes it possible to provide an inaccuracy of simplified methods that does not exceed 1 % in relation to the goniophotometric method. It is in dicated that in order to find a universal factor applicable for the entire range of linear low-pressure UV lamps, the development and the analysis of statistical data is required.

DownLight Simulation with LED Module in the program «Compass-3D»

The design of LED lamps of the DownLight type is considered. Their main advantages over traditional lamps with incandescent and fluorescent lamps are shown. 3D-modeling of the DownLight type luminaire and its elements was carried out in the «Compass-3D» program. Keywords luminaire with LED module; Compass-3D; luminous intensity curve (LIC) of light device