A time-marking device for serial radiographs.

Abstract

An accurate knowledge of the time relationship of serial films is frequently of value during the course of angiographic examinations in order to assess whether and to what extent anatomical narrowings cause circulatory delay. When the films are taken on a serial changer, such as the Elema Schönander, marking devices are available. Such commercially available timers, which are activated by the serial changer, are not always accurate. Furthermore, no timing device is available for peripheral arteriograms obtained on a Garrow box. For these reasons it was decided to develop a new time marking device which is not linked to any particular serial changer. It is desirable that the time should be recorded on each film as it is exposed, so as to obviate clerical errors. This also assists in the sorting of the films which can become a time-consuming operation when there is a large series. The device has to be mobile so that it can be used with different types of X-ray apparatus and placed in the corner of fields of varying size. It has to be small enough not to encroach unduly on the X-ray field and thin enough to slip under the patient without causing discomfort, as in many instances the patient extends beyond the area of irradiation. A timing device can be powered either by clockwork or by a constant-speed electric motor. Clockwork has the disadvantage that the operator must remember to wind it up: an electric motor is more convenient in a busy department.