Roentgen-Stereometry and Sectional Display of Computed Three-Dimensional Dose Distributions in Radio-Therapy
The introduction of the computer to radiation treatment planning problems, especially to the calculations of dose distributions in irradiated patients, has led to a critical investigation of the fundamental data fed into the computer. While the physical data of the radiation are known to an accuracy of one or two percent, the data to be obtained from the patient are still subject to major inaccuracies. These mostly anatomical data are body outlines, sizes and positions of tumors in the patient, sizes and positions of tissue-inhomogenities as lung, bone, and gas in the bowel, the position of healthy organs which are sensitive to radiation and in proximity to the treatment area, and the exact position of interstitial or intracavitary sealed radioactive sources such as radium, cobalt, or caesium applicators, radio-gold or radon seeds, iridium wires, and others. In all cases a three-dimensional localization, that means a three-dimensional measurement of position and size, of certain structures at or inside the patient is necessary. A roentgen-stereoscopic method, described in the paper and in the demonstrations of Leydolph and Rosenow, was found to be best fitted to these problems of localization, because it anables a very accurate, and as well as a very fast and simple estimation of stereometric x-ray films.