X-ray or gamma ray systems or devices – Accessory – Testing or calibration
Patent
1996-07-08
1999-02-16
Church, Craig E.
X-ray or gamma ray systems or devices
Accessory
Testing or calibration
378210, G01D 1800
Patent
active
058728309
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention refers to methods and devices to perform measurements on beams of X-rays. When required the same methods and devices may also be utilized to perform measurements on radiation of other wavelengths, such as visible light.
In particular the invention refers to a simplified method and a device to determine the size and/or the location of focus of an X-ray tube- However, it can also be utilized in other applications, such as for example to determine the location of a light source that is utilized for adjustment of an X-ray apparatus.
DESCRIPTION OF THE BACKGROUND ART
An object of the present invention is to be able to control the position and the size of the focal spot of the X-ray tube in an X-ray equipment for diagnostics which normally is provided with an X-ray tube with rotary anode, but the technique according to the invention can also be utilized in other equipment. By determination of the size of the focal spot of an X-ray tube, a method according to IEC 336 is normally used. By means of a slit-camera a longish image is achieved which constitutes a projection of the extension of the focal spot in one direction, the image of which is recorded photographically and can be analyzed by a micro-densitometer. This is a time-consuming and circumstantial procedure, which in addition can be marred by unnecessary error sources. When measuring on weak X-ray generators which are utilized for instance in connection with mammography, a large number of exposures have to be made to obtain sufficient density on a film of the image through the slit. Differences in the position of the X-ray tube and of the measuring equipment at the various exposures may occur, whereby the image does not become correct. Moreover, only this part of the measurement becomes time-consuming, thereafter time has to be included for development and read-out of the image.
SUMMARY OF THE INVENTION
In the present invention it is possible by one single exposure to produce data for an image of the focal spot of the X-ray tube. This is achieved by means of a design according to the subsequent patent claims. According to the invention a slit is utilized in the same manner as in the slit camera but instead of a photographic film for the recording, one uses a line sensor with sensor elements being arranged parallel to the slit and at least cover the width of the slit image in question. With this arrangement a pronounced electric signal is obtained from a single exposure due to each line sensor element sensing the signal from sections across the slit along the whole length of the sensor.
Besides giving a strong output signal the utilization of the line sensor has also other advantages. Common CCD-sensors for visible light can normally not be utilized to detect emission of X-rays due to the fact that electronic components belonging to the sensor elements spread out over the sensor surface are negatively influenced by emission of X-rays, whereby the sensitive components cannot be screened from the radiation. At the line sensor, the electronic components are collected at the rear and of the sensor elements. This end can be screened off from X-ray beams without the sensor area being reduced. Sensors which normally are designed for light may thereby also be used for detection of X-ray emission. This is particularly advantageous if the same slit and sensor can be used both for measurement of X-ray focus and of the lamp for visible light that usually is used for adjustment of the image field on a patient, since the conformity between visible image field and X-ray image field then may be controlled.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those
REFERENCES:
patent: 4442539 (1984-04-01), Aichinger et al.
Church Craig E.
RTI Electronics AB
LandOfFree
Device and method of imaging or measuring of a radiation source does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device and method of imaging or measuring of a radiation source, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device and method of imaging or measuring of a radiation source will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2068729