FI90618C - Panorama X-ray exposure automation - Google Patents

Description

! 90618

Panorama X-ray exposure automation. Exponering auto-för panoramaröntgenanordningar.

The present invention relates to the automation of a panoramic X-ray machine, which enables to obtain a properly panoramic X-ray irrespective of the patient's anatomy and tooth structure by utilizing the intensity of radiation transmitted by the patient to the anatomy of the patient, e.g.

Known automation implementations of panoramic devices define imaging values, e.g., x-ray tube kV 15 and mA, film transfer rate, or rotation speed of a beam supporting an x-ray tube and film cassette, by measuring a patient's transmitted radiation either on a single sample or at a given time.

A disadvantage of previous methods is that the adjustment of imaging values does not take into account differences in patient structures, whereby irregularity of patients' jaw and teeth can spoil the imaging result: Single-sample adjustment is particularly susceptible to virulence because it is the specimen that may exhibit irregularities; nail plug, tongue, cervical vertebrae, tooth patches, etc. Continuously adjustable automation is also prone to faults, especially amalgam sites in the dental area, or lack of some of the teeth causes blunting errors.

There are also various ways of predicting the equivalent thickness of the skull, e.g. based on patient weight, skull diameter, etc., even some of which are even paten-35 powered by exposure automation. The disadvantage of these methods is that no single secondary measure invariably correlates with the equivalent cranial thickness, but the correlation is statistical and the exceptions are large and common. In fact, the skull equivalent thickness is affected by many factors, such as size, gender, and particularly age (osteoporosis), as well as racial characteristics.

An advantage of the claimed invention is that the selection of imaging values can be made on the basis of reliable measurement, e.g., by measuring the intensity of radiation passing through a desired jawbone site. This object is achieved by the invention on the basis of the features set forth in the appended claims.

15

The invention will now be described with reference to the accompanying drawing, which schematically illustrates a description arrangement according to the invention.

Behind the imaging means of the panoramic X-ray device (Figure 1), e.g., the film cassette 1, is located one or more X-ray detectors, e.g., a photodiode 2, amplified by a circuit board amplifier and applied to a control unit to adjust the darkness of the film. The reference values of the voltage and / or tube current of the X-ray tube are changed by the difference amplifier of the control circuit of the X-ray generator 6 and / or the motion speeds are adjusted accordingly by changing the adjustment value of the motion motion control elements, e.g.

«. . ·

The x-ray device according to the invention is thus provided with means 2, 3 for measuring the radiation transmitted by the patients 8 at certain points and for adjusting the imaging values (e.g. 35 tube voltage kV, tube current mA) and speeds of imaging movements 3 90618 (means 5, 6, 7). To this end, the device is provided with a control unit 5 which is able to deduce the measurement values of the radiation intensity of the anatomy by examining the measurement values at short intervals (e.g., 50-150 ms) and the boundary between soft tissue and bone tissue (e.g. peripheral areas). The measured values directly determine whether the cervical vertebra is at the beginning of the imaging. The recognition of the anatomy of the image itself is thus a basic 10-pattern pattern recognition, using well-known regularities in panoramic X-ray images.

When using the arrangement of the invention, the imaging is typically performed by searching for a location in the radiation information to begin imaging the jawbone, followed by adjusting the imaging values at the post-jawbone epithelial layer. The adjustment can be limitedly corrected even further downstream of the jaw epithelial layer.

20

The imaging arrangement according to the invention can advantageously be used so that before actual adjustment of the imaging values it is examined whether the cervical vertebrae are imaged by the imaging device 1e, followed by a rough adjustment of the imaging values. 25 after the beam 8 has passed the cervical vertebrae.

4

An imaging arrangement for automatically adjusting imaging values in a panoramic X-ray device, wherein the radiation intensity transmitted by 5 patients during imaging is measured by a detector (2) consisting of an X-ray photodiode whose signal is amplified by an amplifier (3), adjusting the imaging values affecting the film darkness by adjusting the imaging values of the X-ray generator (6) and / or changing the irradiation time through the motion motion guides (7) at desired locations, characterized in that the control unit (5) 2) 15 measures the radiation intensity of the patient at short intervals at one or more locations.

An imaging arrangement according to claim 1, characterized by searching the radiation information for a point at which imaging of the jawbone begins, after which imaging values are set at a position downstream of the jawbone epithelial layer.

Imaging arrangement according to claims 1 and 2, characterized in that the adjustment made by the imaging arrangement according to claim 2 is corrected to a limited extent further downstream of the jaw epithelial layer.

Imaging arrangement according to claims 1 and 2, characterized in that, before the actual adjustment of the imaging values, it is examined whether the neck vertebrae are imaged on the imaging device, after which a rough adjustment of the imaging values is performed after the beams (8) have passed.

Claims (4)

5 96018 An imaging system for automatically controlling image values in a panoramic X-ray device, in which the patient penetrated the radiation intensity for short periods of time is measured with a detector (2), which consists of an X-ray radiation measuring photodiode, the signal of which is amplified by an amplifier (3 ), from which a signal (4) is fed to a controller (5) which, at desired locations, regulates the image values of the film 1. Blackness by controlling the image values of the X-ray generator (6) and / or by changing the irradiation times by mediating controls ( 7) for the image movements, characterized in that the controller (5) is arranged to detect during imaging the imaged site, for which purpose said detector (2) measures the patient's penetrating intensity at one or more places for short intervals of time. -smiles. 2. Image system according to claim 1, characterized in that a point in the radiation information is searched, at which point one begins to image the edge of the jaw bone, after which the image values of a point after the epithelial layer of the jaw bone are controlled. 25 3. Imaging system according to claims 1 and 2, characterized in that the control which has occurred with the imaging system according to claim 2 is limited to a correction in place of an epithelial layer following the epithelial layer. 30 4. Imaging system according to claims 1 and 2, characterized in that before the actual control of the image values is examined, whether the nerve vertebrae are imaged on the imaging device, after which coarse control of the image values is performed after the beam (8) passes past the nerve vertebrae.