Análisis de errores en la determinación de dimensiones lineales a partir de una radiografía / Errors analysis in determination of lineal dimensions of a radiography

Se discuten las relaciones geométricas de la imagen en una radiografía. Se obtiene una fórmula sencilla que relaciona el tamaño de la imagen y el tamaño real de un tumor que yace en el plano medio entre la superficie superior del cuerpo y la película. Se analizan los errores debido a la incertidumbre experimental y se demuestra que dentro de ciertos límites una fórmula simple es suficientemente precisa

Sievert, gray and dose equivalent.

The concepts of physical quantity and physical units of measurement are presented. The relations between quantities, the names and symbols for SI (International System) base units, derived units and special names of SI units are illustrated. From the definition of the radiation quantity dose equivalent, the SI unit for this quantity is shown to be dimensionally identical with the joule per kilogram. The sievert (Sv) is the special (restricted) name for the SI unit of the quantity dose equivalent, with 1 Sv = 1 J/kg.

Radiation parameters of 6 to 20 MeV scanning electron beams from the Saturne linear accelerator.

Depth doses of the scanning electron beams from the Saturne Therac-20 linear accelerator at nominal energies of 6,9,13,17, and 20 MeV were measured in polystyrene using a thin window parallel plate ionization chamber. Central axis depth dose curves are derived and are analyzed according to the method of Brahme and Svensson. For each of the five electron energies, values are obtained for the most probable energy at the absorber surface Ep,0, the practical range Rp, the 50% range R50, the therapeutic range R85, the electron dose gradients, total collision energy losses, and other radiation parameters, and these are compared to corresponding values for electron beams from a 22 MeV medical microtron and a 20 MeV betatron.