Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
  • A61B6/58—Testing, adjusting or calibrating thereof
  • A61B6/587—Alignment of source unit to detector unit
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
  • A61B6/08—Auxiliary means for directing the radiation beam to a particular spot, e.g. using light beams

Definitions

• This invention relates to a method in the positioning or adjustment of ionizing radiation fields.
• the invention is preferably intended to be used in the positioning of X-ray equipment in medical attendance.
• the invention also relates to apparatus for carrying out the method.
• X-ray examinations it is of great importance that the equipment is correctly set or positioned in relation to the object to be radiophotographed.
• the radiographes shall give the necessary basis for decision and possible treatment measures, while it at the same time is desirable that patient and personnel are subjected to radiation as little as possible.
• One method is to make the field of light fall upon an X-ray film, on which the limits of the field of light are marked, e.g. by means of a metal wire, which is impermeable to the X-rays. Without changing the settings or positions, the film is then exposed, and a comparison of the pictures of the metal wire and the outer boundry lines of the exposed surface indicates the agreement or coincidence between the field of light and the field of X-rays.
• Another method is to utilize a plate, which is covered with a fluorescent material. When utilizing such a plate, the field of light is adjusted to coincide with marks on the plate, after which an X-ray exposure or fluoroscopy is carried out.
• Fluoroscopy is a continous X-ray exposure with lower photon density and accordingly less power than a normal exposure. It is then possible to observe the surface' which is impinged by the X-rays and to compare said surface with the light image or pattern.
• This method is comparatively rapid but entails the essential drawback, that the person carrying out the observations is subjected to the x-radiation, which constitutes an unnecessary risk factor. Furthermore, the result of the setting or positioning measurements can not be stored.
• the risk of becoming subjected to x-radiation is reduced, but the method comprises an uncertainty factor, in that the film may be displaced with respect to the rest of the equipment and it takes time to establish the result, since the film has to be developed before being read off.
• the object of the present invention is to provide a method and an apparatus which permit a rapid measurement of the agreement or coincidence between the field of light and the field of radiation without subjecting the personnel to unnecessary radiation.
• a further object of the invention is to make possible storage of the results of the measurements for reading off on a desired occasion. In the first instance, reading off is carried out immediately after that the x- radiation has been turned off, but it is also possible to provide the apparatus with components for storing the measurement result during an extended period.
• a still further object of the invention is to provide an equipment, which permits obtainment, directly at the reading off, of the measure of the tolerance, i.e. the deviation between field of light and field of radiation.
• This invention relates to a method in the positioning or setting of ionizing radiation fields in X-ray equipment and the like, the intended extension of the radiation field on a surface being indicated through lighting, by means of a lamp or another device with the corresponding function, e.g. laser, coupled to the equipment.
• a measuring plate is lighted by means of the lamp, and the light image is compared with that image which the field of radiation gives on the same measuring plate, with unaltered positioning or setting of the equipment.
• the adjustment of the image of light is carried out in such a way, that the image coincides with certain marks on the measuring plate, after which the plate is irradiated with x-radiation with unaltered positioning of the equipment.
• the radiation picture of the x-radiation is read off by means of detectors and is compared with the picture of light.
• the result obtained is indicated by means of light-diodes or simular means in the measuring plate. This indication can be accomplished through different colours in dependence of the coincidence between the field of light and the field of radiation at the respective detectors.
• Fig. 1 shows the upper side of a measuring plate in a preferred embodiment of the invention.
• Fig. 2 is a block diagram of the control electronics associated with the measuring apparatus.
• the plate shown in Fig. 1 is provided with four corner marks 2, 3, 4, 5, located on the plate at a little distance from the corners of the plate. These corner marks delimit on the upper side of the plate a field which is a little less than the plate proper. Approximately at the center of each of the four imaginary reading off lines and perpendicularly thereto, there is provided a line of light-diodes 6, 7, 8, 9, by means of which the obtained result of the measurement is indicated. In association with the light-diode sensors, e.g. photo- transistors or photo-diodes, are provided for reading off the ionizing radiation.
• the light-diode sensors e.g. photo- transistors or photo-diodes
• the measuring plate is placed under the X-ray equipment and is illuminated by the field of light, the equipment and the plate being so adjusted in relation to each other, that the field of light coincides with that field or area of the plate, which is delimited by the four corner marks 2, 3, 4, 5.
• the impact pattern of which is read off by means of the detectors located in connection with the light- diodes.
• the information on the field of radiation thus obtained is indicated by the light-diodes or is stored in the equipment and extracted on a desired occasion.
• the light-diodes may be given different colours, and the example shown in Fig.
• each group of light-diodes contains in each group of light-diodes eleven diodes having three different colours.
• there are five diodes emitting green light outside these two diodes on each side which omit yellow light, and outside these diodes one further diode on each side, which emits red light.
• an indication is immediately obtained of the position of this line and of the extent of deviation from the limiting line of the field of light.
• the tolerance or deviation is often expressed in per cent, which means the distance between the limiting lines of the field of light and those of the field of radiation in per cent of the distance from the focus of the X-ray source to the surface of the measuring plate.
• the colour of the light-diode can easily be translated into an interval of percentile deviation.
• the tolerance demands may e.g. be comprised in the interval 0,25 - 1 %, and e.g. green light may designate 0,5 % deviation or less, and yellow light 1 % deviation at the most. Red light (or no light) means a deviation greater than 1 %.
• FIG. 2 there is an example of a block diagram of the control electronics of a measuring apparatus according to the invention.
• Each set or group of light diodes 2, 3, 4, 5 corresponds, or is correlated, to a set of detectors 10, 11, 12, 13, each comprising eleven detectors, so that each light- diode corresponds to one detector.
• the apparatus also comprises a signal amplifier 14, a memory unit 15, a logical circuit 16 for driving the light-diodes, and a driver or exiter 17.
• a photo-diode 18 for trigging the measuring sequence, an oscillator 19 and logics 20 for synchronizing of measuring or display sequences.
• the method according to the invention permits a rapid and simple measurement of the coincidence or agreement between field of light and field of radiation.
• the results obtained have a great accuracy and are reproducible.
• the measurements can be carried out by personell having no special technical education, and the measurement results obtained can be read off after that the x radiation has been turned off and can also be stored for reading off on a desired occasion.

Landscapes

• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Medical Informatics (AREA)
• Engineering & Computer Science (AREA)
• Radiology & Medical Imaging (AREA)
• Molecular Biology (AREA)
• Biophysics (AREA)
• Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
• Optics & Photonics (AREA)
• Pathology (AREA)
• Physics & Mathematics (AREA)
• Biomedical Technology (AREA)
• Heart & Thoracic Surgery (AREA)
• High Energy & Nuclear Physics (AREA)
• Surgery (AREA)
• Animal Behavior & Ethology (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Apparatus For Radiation Diagnosis (AREA)
• Measurement Of Radiation (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20383222

Family Applications (1)

Country Status (3)

Cited By (3)

Citations (4)

• 1991
  • 1991-07-02 SE SE9102051A patent/SE9102051L/sv not_active IP Right Cessation
• 1992
  • 1992-07-02 AU AU22921/92A patent/AU2292192A/en not_active Abandoned
  • 1992-07-02 WO PCT/SE1992/000509 patent/WO1993001697A1/en unknown

Patent Citations (4)

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