The Evolution of Dosimeters in Roentgen Ray Therapy

Abstract

The First Roentgen Ray Dosimeter The first estimates of quality and quantity of roentgen rays were made by observations of the density of the shadows cast by the bones and flesh of the operator's hand upon fluoroscopic screens and photographic plates (1896). The injuries which resulted from this procedure led to the use of the bones of skeleton hands imbedded in wax as a substitute for living hands. This contraption was called the “;osteoscope.” It was the first roentgen dosimeter. Arithmetic Computation of Roentgen Ray Dose Radiologists soon learned that the roentgen ray skin dose depended principally upon four technical factors: Voltage at the tube which was measured by inches of spark gap, current through the tube measured in milliamperes, focal skin distance in inches, and time of application. These factors then were arranged in formulae to calculate skin dosage with unfiltered and later with filtered roentgen rays for different treatment conditions (1, 2, 3). The pattern of a formula in general use w...