[Bisectorial small-angle pendulum irradiation alternatively to other methods of 60Co-teletherapy: valence and volume...

A comparison is made between five irradiation methods, the dose distribution and volume doses of which had been ascertained by means of two phantoms presupposed differently large. Of the two methods of small-angle pendulum irradiation, the bisectorial monaxial pendulum technique turns out to be a practicalbe alternative to fixed-field and rotation irradiations. Similarly to fixed-field irradiation with two opposed fields, to which, after all, this technique is superior in every respect, it makes possible a relatively simple spatial irradiation planning. In this regard it is also more favorable than the rotation irradiations, though they give security of a more homogeneous load to axially parallel focuses; but an oblique position of the focal axis can be compensated only by an extension of the target volume and consequently augmentation of the volume dose. The necessity of confining to a certain extent the sum of absorbed energy is accentuated.