Derivation of isodose charts for radium tubes

Dosage calculations for gynaecological insertions using a mini-computer

“…The constant K was determined by normalizing the calculated dose at a single point to that obtained by measurement (Buchan and Griffin, 1969). Figure 4 illustrates the agreement obtained between the calculated and measured values along the u and v axes (Fig.…”

“…Clearly such a model could be extended to generate the isodose distribution about any radium or caesium tube or needle, with only slight modifications. Using the same program, but with modifications to the physical positions of the point sources Technical notes to make them compatible with the active volume of a Radium-226 E4 tube, satisfactory agreement has been obtained to the data of Buchan and Griffin (1969) merely by adjusting the normalization constant to that shown in Table I.…”

“…For monoenergetic y rays, this scatter factor may be regarded as varying exponentially with distances (Goldstein and Wilkins, 1954). When a range of y-ray energies are present Buchan and Griffin (1969), along the u and v axes.…”

“…Table I. The parameters /*i and ^2 were obtained by fitting the published air-tissue correction factors (Hale, 1958, Shalek andStovall, 1969) for distances of 1-10 cm from the source. Small adjustments were made to the parameter / X2 to obtain the closest possible fit of the calculated dose rates to the data of Buchan and Griffin (1969), over these distances.…”