The relationship of the detectability to the size and depth in water of a cold lesion and the total image counts (information density) of scintigram were assessed by means of the averaged receiver operating characteristic (ROC) curves. As a result, the detectability of a cold lesion depends on the total image counts required to compose a scintigram and the dot size of a micro-dot imager. The more the total image counts and the smaller the dot size, the better the detectability of the cold lesionis. The contrast between the cold lesion (signal) and the background (noise) is improved by effective utilization of the film characteristic curve. A cold lesion of 1.5 cm in diameter can not be detected at a depth of 3 cm, even if the most suitable condition is chosen. However, a cold lesion of 2.3 cm in diameter can be detected perfectly. Similarly, a cold lesion of 9 cm in depth is almost imppossible to detect no matter what the size used in this study. It seems that the depth with meaningful information can be obtained is up to 5 cm. As the total image counts of a scintigram increases, the detectability of a cold lesion increases.
To make the most of the locational information in a three dimensional picture, software was developed for therapeutic planning in the field of external irradiation. It contains algolism specifications for a volume calculation based on a newly devised formula for size calculation with an introductions of the concept of "target volume" for therapeutic planning. In the field of X-ray dose calculation, it permits the calculation of compound X-ray dose distribution resulting from the differences in the irradiation method. The major points are : 1. The three dimensional distribution of a X-ray dose may be shown on a given cut surface picture. 2. Calculation of the three dimensional distribution of a compound X-ray dose 3. Volume calculation through application of a space-compensatory formula 4. Calculation of a target-absorbed dose
To observe microstructures on the X-ray cinematography by 0.6mm focal spot, usefulness of enlarged shooting was studied. As a result, even at a focus of 0.6mm, the enlarged shooting (ca. 1.7-fold) revealed the superior total M.T.F. than that of contact photography. Furthermore, Groedel effect upon magnification was as good as the grid system. In the cardiac catheterization by 0.6mm focal spot being employed most frequently at present, the enlarged shooting without using grid is a useful method. Thus, it is considered to take up this method as much as possible.
The purpose of this study was to find out the best, standard method for X-ray projection in skyline view radiography of the patello-femoral joint. The materials which we used in this studies were 100 anatomical specimens of the patella and the femur, and the knee joint X-ray films of 330 patients with various diseases. Primarily, the anatomical individualities of the patella and the femur were studied. Then, secondarily, we determined the radiographical standard for X-ray projection of the patello-femoral joint considering its biomechanical function. "The anterior axis of the patella" and "the knee-greater trochanter axis" were found to be the most reliable axes in standard X-ray projection to obtain the best skyline view. The advantages to use these two axes as parameters in theskyline view were in grasping the inclination and position of the patella in various flexion angles of the knee exactly, in the radiographic procedure, in obtaining a high correlation to the axis of the central groove of the femoral patellar suiface, and rmakeit easier to obtain a constant direction of X-ray beam against the patello-femoral joint. The methods of our skyline view radiography in supine and standing positions were described in detail.