[Optimization of verification photographs in thoracic wall irradiations (so-called tangential field technique) in breast carcinoma. A short technical-methodical report].

When irradiating under high voltage condition, verification photographs prove to be difficult to take if the Gantry position is not aligned to 0 degree respectively 180 degrees, since the patient is being irradiated diagonally. Under these conditions it is extremely difficult to align the X-ray-cartridge vertically to the central beam of the therapeutic radiation. This results in, amongst others, misprojections, so that definite dimensions of portrayed organ structures become practical impossible to determine. This paper presented describes how we have solved these problems on our high voltage units (tele-gamma cobalt unit and linear-accelerator). By using simple accessories, determination of dimensions of organ structures, as shown on the verification photographs, are made possible. We illustrate our method by using the so-called tangential fields technique when irradiating mamma carcinoma.