| 摘要 |
<p>The dental x-ray equipment consists of a framework (2), which supports a film holder (3) containing x-ray film (4), a dose detector (5) and an x-ray tube (6). The head of the patient is held in a support (7) ready for taking a series of pictures of tooth or jaw, by rotating the equipment around his or her head. During the filming run, the dose of the x-ray beam is controlled so that after the passing of the pre-set exposure time, an optimum film density ensues. The dose detector (5) is connected to a control unit (8), to whose input (9) a set value signal is applied (10). This set value is influenced by the output signal of a digital- analogue converter (11) which receives its input from a storage unit (12). The store (12) is controlled by a positional transmitter (13) for each position of the exposure unit (1). The set value for the dose output can therefore be related to the x-ray film speed.</p> |
