Subject(s)
Eye Diseases/surgery , Education, Medical, Continuing , Humans , India , Mobile Health UnitsABSTRACT
A rapid non-destructive and sensitive technique is used by which total body water and its rate of turnover (excretion) in human subjects can be easily measured. Subsequently, a simple calculation is made in estimating the total body fat and lean body mass. The measurements are, therefore, expected to shed useful light on the measurement technique as well as on the movement of body water in humans, and this will glean an understanding of physiological laws governing such movements. The method employs the activation of deuterium in water by bremsstrahlung radiations which are produced by stopping 3 MeV electrons in a gold target. The detection of photoneutrons, so obtained in the reaction 2(1)D(gamma, n), is accomplished by the capture of fission fragments in Solid State Nuclear Track Detector (SSNTD) issuing from the 235U(n, f) reaction. These fission events are then automatically counted by a spark counter. Thermal neutrons, required for the 235U fissioning, are obtained by employing a graphite moderator assembly at the core of which water and urine samples are being irradiated. The development of a few basic measurement parameters and their utilization in such measurements are also reported in the paper.
Subject(s)
Body Water/metabolism , Deuterium , Humans , Kinetics , Time Factors , UraniumABSTRACT
Lyoluminescence sensitivity of five different saccharide powders to electron irradiation has been determined using luminol solution as a solvent. Effect of electron energy variation in the range of 5-20 MeV on the lyoluminescence yield has been measured. The light conversion efficiencies of different saccharides irradiated with x-rays, beta-particles, gamma-rays, fast electrons, 170-MeV/c pi(-)-mesons and 8-MeV neutrons have been calculated. Factors affecting light conversion efficiency, sensitivity and accuracy of measurements are discussed.
Subject(s)
Carbohydrates/radiation effects , Luminescent Measurements , Beta Particles , Electrons , Gamma Rays , Glucose/radiation effects , Mannose/radiation effects , Mesons , Neutrons , Powders , Radiation Dosage , Thermoluminescent Dosimetry , Trehalose/radiation effects , X-Rays , Xylose/radiation effectsABSTRACT
The light emitted when pion irradiated glucose is dissolved in luminol solution has been found to be proportional to the pion beam depth dose distribution in water as determined by a TE ionisation chamber. The lyoluminescence of glucose overlaps very closely with the response profile of the ionisation chamber to the 170 MeV/c pi--mesons giving a Bragg peak to plateau ratio of 3:1. In comparison, the thermoluminescence response of LiF (TLD-700) to pions has been found to deviate significantly from this ratio. The close tissue equivalence of glucose, non-toxicity and its excellent lyoluminescent retention properties are important advantages over currently used dosemeters in clinical pion therapy, especially when direct in vivo measurements are considered. Pion doses ranging between 0.5 Gy (50 rad) and 30 Gy (3000 rad) were measured with an accuracy +/- 5% and reproducibility 3-5%.
Subject(s)
Radiometry/instrumentation , Radiotherapy Dosage , Radiotherapy, High-Energy , Elementary ParticlesABSTRACT
Fifty cases of amblyopia, including some cases of eccentric fixation, which had previously been successfully treated by various therapies (conventional occlusion, red filter occlusion and pleoptics) were followed up from 12 to 68 months. Fifteen cases (30%) deteriorated to pretreatment level during the follow up. Deterioration was found to be greater in cases over the age of 15 years and in cases who did not follow the instructions given to them after cessation of therapy.
