[2-dimensional ultrasonic scanning for irradiation planning]

The paper is concerned with the results of the utilization of echotomography in the topometric preparation of patients with malignant tumors for irradiation. Proceeding from the examination of 600 cancer patients in the All-Union Cancer Research Center. USSR AMS, it has been established that echotomography makes it possible not only to define the borders of pathology in the peritoneal cavity and retroperitoneal space but also to specify the relative position of the adjacent internal organs. Some practical aspects of the use of ultrasound for topometry are discussed. A possibility of using this method for the three-dimensional planning of irradiation is indicated. Using an echotomoscope one can obtain a contour of the section of a soft phantom with an accuracy of 5 +/- 1 mm that significantly exceeds the limits of precision of a contour measured with the help of a lead band where it equals 10 +/- 7 mm. Echotomography makes it possible to get a contour in any plane. In view of certain limitations of the echotomographic method one should also resort to x-ray methods for the topometric planning of irradiation to specify the position and size of the bearing osseous structures. While converting reduced ultrasound images in the scale of 1:1 the optic method with an episcope proved to be the most accurate one where an error of reproducibility of a contour reaches 1 mm. In the use of an optical-electronic device this value exceeds 10 mm and corresponds to 4 mm while utilizing a pantograph.