An Optical Device for the Accurate Alignment of an X-ray Beam
1939; Wiley; Volume: 12; Issue: 137 Linguagem: Inglês
10.1259/0007-1285-12-137-257
ISSN1748-880X
Autores Tópico(s)Advanced Radiotherapy Techniques
ResumoIn the treatment of patients by X rays it is desirable to know the precise location of the beam at the exit, as well as at the incident surface. This knowledge enables much more exact positioning of the patient to be made and allows of the use of either natural or artifical surface markings in the alignment. As an example, we may quote the necessity for accurate direction and position of the beam if strip fields are to be used effectively in the treatment of an œsophagus. The construction of any mechanical apparatus for defining the position of the beam in space is not easy owing to the large focal skin distances employed in high-voltage therapy, and the consequent difficulty in designing a light and rigid structure. We have recently designed and made use of the following simple device which has been found to be eminently practical and to increase considerably the ease and accuracy of setting up the patient. A brass tube (Fig. 1), 16 in. long, is fitted with a stop A at one end, having a ¼ in. diameter central hole. Into the tube at the other end is fixed a ring B, mounted on cross wires. Near the X-ray tube and on the central axis of the X-ray beam is mounted a small pea lamp, while the end of the treatment applicator fitted to the X-ray tube has in it a small hole a few millimetres in diameter.
Referência(s)