| 摘要 |
PURPOSE: To improve the reliability of a diagnosis of a tumor by xeroradiography by measuring the potential of an object area of an electrostatic image and finding the mean potential, discriminating between image capture and emphasization, and developing the electrostatic image with toner. CONSTITUTION: For a diagnosis of a breast tumor, specially, photography of the breasts, a photoelectric conductor which is charged electrostatically with X rays transmitted through the object is exposed to form an electrostatic image of the object on the photoelectric conductor. Then the potential in the object area of this electrostatic image is measured to determine the mean potential Vav in the object area. Then the electrostatic image is developed with toner by using a developing electrode biased with a potential Vb which is close to the mean potential, but other than a potential having a potential value corresponding to the featured part of the image selected to emphasize the object area. Consequently, a toner image having the contrast emphasized in the object area is developed. Here, a detector is a photoelectric conductor which is charged electrostatically with the potential V0 before the exposure. Further, the voltages corresponding to the contrasts of areas 1 and 2 are represented as V1 and V2 . |
