[en] An acrylic head phantom was irradiated during a computed tomographic scan with four commercial scanners. Measurements of the spatial distribution of the radiation dose on the surface and internal to the phantom were performed for the scan plane and the scattered beam at various distances from the scan plane. The surface scatter dose was found to be considerably smaller than that for internal scatter. A significant increase in radiation exposure within the head phantom due to internal radiation scatter, and an asymmetrical primary beam profile for dual slice scanners were also noted. (orig.)

[en] Radiation dosimetry measurements on angiographer, X-ray technician and patient were performed during 18 femerocerebral angiograms. Lithium fluride (LiF) thermoluminescent dosimeters were placed on various body areas to measure X-ray exposure. The results of this study indicate that radiation exposure received by medical personnel are well within the maximum permissible dose range established by the National Council of Radiation Protection. However, radiation exposure levels to radiosensitive areas of the patient are significant. A method to reduce patient exposure during femerocerebral arteriograms is suggested. (orig.)

[en] Based on MRI diffusion's and perfusion, a new criterion for detection and the healing progress of damaged tissue is suggested. The study is based on the ratio of capillary radii in symmetrical damaged and normal tissue neighboring spaces. The apparent diffusion coefficient and cerebral blood flow were measured in the brain tissues of six male wistar rats utilizing suggested MRI measurement techniques. The apparent diffusion coefficient values of damaged and normal regions were (392±34.1) x10^-6 mm^2s-1 and (659±40.7)x10^-6 mm^2s-1, respectively. The cerebral blood flow values of damaged and normal regions were 14.5±10.13 mi/min/100 g and 125±41.03 mi/min/100 g, respectively. The geometrical parameters of the capillary for damaged and normal regions midle root/√ Λ, where midle root is the mean radius and Λ is the mean capillary segment length , were calculated to be 5.45±2.01mm⁰.5^g-0.5 (mean±Sd) and 12.8±2.04 mm⁰.5^g-0.5, respectively. Furthermore, based on constant Λ, the damaged, versus normal region, mean radius, was shown to follow the ^criterion^midle root Damaged≅0.13xmidle root Normal. A further analysis was conducted through suitable theoretical modeling and assumptions for the above-mentioned criterion. The analysis showed a distinct difference between normal and damaged tissues in various healing progress conditions. Moreover, a new image, namely, Diffusion/Flow map (DF map), which is a mere division of the ADC map to the cerebral blood flow map, was introduced and utilized to contrast between normal and damaged tissue