quality assurance procedure to monitor mechanical stability on-Linear accelerator-based on stereotactic radiosurgery/sterotatic radio therapy

Stereotactic irradiation, either in the form of stereotactic radiosurgery [SRS] or stereotactic radiotherapy [SRT], of brain lesions requires high precision accuracy in the isocenter, the main determinants were gantry and couch rotations. It is thus necessary to evaluate the isocenter variation due to gantry and couch rotations in the particular setup for SRS/SRT. This paper describes the accuracy of Patients' immobilization and the variation in the isocenter of a Siemens PRIMUS M6/6ST linear accelerator-modified for adapting a couch-mounted radiosurgery system. The accuracy of Patients immobilization was excellent in over twenty patients with 95 setups and 2375 scalp measurements. Ninety two percent of measurements had no displacements from the baseline readings, 7% had 1 mm and one percent had 2 mm displacements. The variations in isocenter position with the table and the gantry rotation were found to be < 0.4 mm with a compounded accuracy of

Study on the effect of nitrogen fertilizer levels on chlorophyll concentration of grape leaves using FT-IR spectroscopy

Methods used to detect N deficiencies during the growing season include chlorophyll meter readings, destructive plant sampling, and soil sampling. Furthermore, diagnostic methods like FT-IR techniques that take advantage of the optical properties of leaves are another possibility to assess the nitrogen status of plants in a field and to assess nitrogen fertility effects on yield. The use of effective FT-IR techniques would eliminate the need for extensive field sampling. Fourier Transform Infrared [FT-IR] spectroscopic technique was used in the present work to study the effect of N-fertilization levels on the concentrations of chlorophyll and nitrogen in grape leaves. Ammonium nitrate [N-fertilizer] was applied after the beginning of vegetative growth by supplying 33.3%, 66.6%, 100%, 133.3%, and 166.6% of the recommended N-fertilizer level, according to the Ministry of Agriculture [50 units N which is considered the level of 100% for comparing during N application]. To establish a range of leaf chlorophyll levels, each treatment was applied to definite row; thus there were 5 different rows, three vines in each line were selected to make the application

effect of ultrasound exposure on erythrocytes sedimentation rate

In the present work, the effect of continuous wave [CW] ultrasound with different frequencies and different intensities on erythrocytes sedimentation rate [ESR] have been studied in vitro. Ultrasound exposure to erythrocytes suspended in saline leads to a change in the sedimentation rate of the cells relative to control. It was found that the change in ESR is a function of ultrasonic intensity and frequency as well as the sonification time. This behavior may be attributed to some changes in the cells due to the nonthermal [mechanical] mechanisms of interaction between ultrasonic waves and the suspended cells

role of ultrasound exposure in erythrocytes defense against hemolysis

In the present work, the effect of continuous wave ultrasound with different frequencies and different intensities on erythrocytes defense against hemolysis has been studied. Ultrasound exposure to erythrocytes suspended in saline during hemolysis caused with low different concentrations of HC1, resulted in deceleration of hemolysis relative to control value of HC1. The calculated hemolysis parameter: relative hemolysis rate [H.R][R], showed a critical concentration of KCl below which the hemolysis is decelerated, which means that the ultrasound plays a role in protecting erythrocytes from hemolysis. Also, ultrasound caused some mechanical changes in erythrocytes, and these changes were frequency and intensity dependant

Hydrocortisone effects on composition of rat bone

Hydrocortisone is sometimes used as a necessary treatment for many diseases. But unfortunately, it usually causes osteoporosis when used for long periods of administration even with normal doses. It produces variations in calcium and phosphate contents in bones. The aim of the present work is to study the effects of long period hydrocortisone treatment on the bone composition of rat hind-leg. Three techniques were used in this study: X-ray imaging to analyze the bone density, molecular spectrophotometer for determining bone composition and histological study to clear the bone structure. The obtained data showed variations in calcium and phosphate contents during the hydrocortisone treatment periods which reached maximum changes after three weeks of treatment. The obtained results by X-ray images indicated changes in the bone density which were supported and found in good agreement with that obtained by both spectrophotometric analysis and structural changes

Functional and destructive effects of microwave radiation on rat brain

Thite rats were in vivo exposed to microwave [MW] radiation in the cellular phone communication frequency range to investigate whether such exposure produces functional or morphological damage in the brain. Three groups were investigated: Mobile phone [MP] handset group, mobile stations tower [MT] group, and microwave source [MS] group. Subgroups of all exposed rats were taken for recovery studies. ECoG activities and histopathological changes were recorded before, during and after microwave exposure. As compared to control animals, EcoG patterns in exposed animals were found to be distinctly altered in each case of exposure. Some fluctuations had been recorded in shape, frequency, and amplitude of EcoG pattern accompanied with structural changes in some brain tissue elements

action of glutamate on the spectral absorbance of retina's fish

Perfusion of the isolated retina of the bulti [tilapia nilotica] A with Ringer's solution containing 5 mM glutamate is shown to cause changes in the optical density of the retina. The absorbance spectrum of these changes were recorded every 15 minutes up to 90 minutes after start of perfusion. The results indicate that there were polyphases changes over the spectrum of wavelength ranging from 350 to 650 nm. The maximum increase in optical density was found to be 25 percent at about 420 nm, while the maximum drop was 60 percent at 440-450 nm