Beam defining system in an electron accelerator

• US 4,140,129 A
• Filed: 04/13/1977
• Issued: 02/20/1979
• Est. Priority Date: 04/13/1977
• Status: Expired due to Term

• Current Assignee: Applied Radiation Corporation
• Original Assignee: Applied Radiation Corporation
• Inventors: Taumann, Leonhard, Heinz, Lothar
• Primary Examiner(s): Cohen, Lee S.
• Application Number:
  US05/787,310
• Time in Patent Office: 678 Days
• Field of Search: 128/404, 128/405, 128/413, 128/422, 128/362, 128/395, 128/396, 128/399, 250/511-513, 250/503
• US Class Current: 250/505.1
• CPC Class Codes: A61N 2005/1089 Electrons
• CPC Class Codes: G21K 1/02 using diaphragms, collimators
• CPC Class Codes: G21K 1/04 using variable diaphragms, shutters, choppers

Abstract

A beam defining system for an electron accelerator has an adjustable collimator with an accessory holder attached thereto for retaining an electron applicator. The electron applicator has an applicator wall which encloses an electron beam cone from the collimator. A frame-shaped spacer which can be brought into contact with the patient is attached to the applicator wall. A frame-shaped limiting aperture additional to limiting members in the collimator are provided on the applicator wall in order to limit the electron-beam cone at marginal regions facing away from the beam defining system.

Claims

1. A beam defining system for an electron accelerator which produces an electron beam cone, comprising:

(a) an adjustable collimator for producing the beam cone;

(b) an accessory holder attached adjacent the collimator;

(c) an electron applicator releasably attached to the accessory holder, said applicator including a tube wall positioned so as to enclose the electron beam cone from the collimator and a frame-shaped spacer movably attached to the tube wall and movable independently of the tube wall into contact with a patient to be treated, said tube wall having a first frame-shaped limiting aperture means associated with the tube wall for limiting edges of the electron beam cone facing away from the beam defining system; and

(d) said frame-shaped spacer having a frame defining a second limiting aperture means having a periphery larger than a periphery of the first frame-shaped limiting aperture means, the second aperture means limiting the same edges of the electron beam cone as the first aperture means when the second aperture means is substantially at a predetermined distance from the collimator and in contact with the patient.

2. A beam defining system in accordance with claim 1, characterized in that said electron applicator has attached thereto a standardized carrier frame which has outer dimensions which correspond to dimensions of the accessory holder of the beam defining system and which is provided with a sensible coding related to a width of the applicator tube wall.

3. A beam defining system in accordance with claim 2, characterized in that the carrier frame has a groove therein and the accessory holder of the beam defining system is provided with a latch engaged with the groove of the carrier frame when the frame is fully inserted in the accessory holder.

4. The beam defining system of claim 2 in which sensor means is provided for sensing the sensible coding and for initiating an adjustment of the collimator in relation to the sensible coding which is sensed.

5. A beam defining system in accordance with claim 2, characterized in that the tube wall includes means corresponding to the coding which prevents the tube wall from intersecting the beam cone except for the frame-shaped limiting aperture means, said means comprising a width of the tube wall.

6. A beam defining system for an electron accelerator which produces an electron beam cone, comprising:

(a) an adjustable collimator for producing the beam cone;

(b) an accessory holder attached adjacent the collimator;

(c) an electron applicator releasably attached to the accessory holder, said applicator including a tube wall positioned so as to enclose the electron beam cone from the collimator and a frame-shaped spacer attached to the tube wall and movable into contact with a patient to be treated, said tube wall having a frame-shaped limiting aperture means associated with the tube wall for limiting edges of the electron beam cone facing away from the beam defining system; and

(d) the accessory holder of the beam defining system being equipped with sensor means for detecting a coding on the electron applicator and switch means for a monitoring circuit and follow-up control for the adjustable collimator being connected to said sensor means.

7. A beam defining system for an electron accelerator which produces an electron beam cone, comprising:

an adustable collimator for producing the beam cone;

(b) an accessory holder attached adjacent the collimator;

(c) an electron applicator releasably attached to the accessory holder, said applicator including a tube wall positioned so as to enclose the electron beam cone from the collimator and a frame-shaped spacer attached to the tube wall and movable into contact with a patient to be treated, said tube wall having a frame-shaped limiting aperture means associated with the tube wall for limiting edges of the electron beam cone facing away from the beam defining system; and

(d) said frame-shaped spacer having mounting means for shifting the spacer along a direction of the beam, said mounting means including a stop means and an elastic means biasing the spacer away from the beam defining system against the stop means, said stop means defining a desired spacing of the beam defining system with respect to the patient.

8. A beam defining system in accordance with claim 7, characterized in that the spacer is mounted with supports which are provided with marking means for revealing shifts of the spacer from contact against the stop means.

9. A beam defining system in accordance with claim 7, characterized in that a switch means for connection to a monitoring circuit for the electron accelerator is associated with the spacer, said switch means being actuated when said spacer is biased against the stop means.

10. A beam defining system for an electron accelerator which produces an electron beam cone, comprising:

(a) an adjustable collimator for producing the beam cone;

(b) an accessory holder attached adjacent the collimator;

(c) an electron applicator releasably attached to the accessory holder, said applicator including a tube wall positioned so as to enclose the electron beam cone from the collimator and a frame-shaped spacer attached to the tube wall and movable into contact with a patient to be treated, said tube wall having a frame-shaped limiting aperture means associated with the tube wall for limiting edges of the electron beam cone facing away from the beam defining system;

(d) said electron applicator having attached thereto a standardized carrier frame having a groove therein and which has outer dimensions which correspond to dimensions of the accessory holder of the beam defining system and which is provided with a sensible coding related to a width of the applicator tube wall;

(e) the accessory holder of the beam defining system being provided with a latch engaged with the groove of the carrier frame when the frame is fully inserted in the accessory holder; and

(f) a switch means being associated with the latch for sensing its position and which also permits switching off the electron accelerator.

11. A beam defining system in accordance with claim 10, characterized in that the switch means which senses the position of the latch is connected in series with a further switch means of the accessory holder for sensing the sensible coding to control the adjustable collimator.

12. A beam defining system for an electron accelerator which produces an electron beam cone, comprising:

(a) an adjustable collimator for producing the beam cone;

(b) an accessory holder attached adjacent the collimator;

(c) an electron applicator releasably attached to the accessory holder, said applicator including a tube wall positioned so as to enclose the electron beam cone from the collimator and a frame-shaped spacer attached to the tube wall and movable into contact with a patient to be treated, said tube wall having a frame-shaped limiting aperture means associated with the tube wall for limiting edges of the electron beam cone facing away from the beam defining system; and

(d) the electron applicator including a carrier plate and the accessory holder includes a slide-in frame receiving the carrier plate, said accessory holder also including column means attached to the slide-in frame for shifting the accessory holder into a desired position in the beam defining system from an alternate position for permitting free mobility of the system while the patient is exposed to X-rays.

13. A beam defining system in accordance with claim 12, characterized in that switch means are provided for monitoring a desired position of the accessory holder.

14. A beam defining system for an electron accelerator which produces an electron beam cone, comprising:

(a) a collimator having adjustable limiting aperture plates for producing the beam cone;

(b) an accessory holder attached adjacent the collimator;

(c) an electron applicator detachably connected to the accessory holder, said electron applicator including a surrounding wall portion positioned so as to enclose the electron beam cone from the collimator, and a surrounding spacer portion positioned so as to further enclose the beam cone;

(d) coding means on the electron applicator for encoding a width dimension of the applicator; and

(e) sensing means on the accessory holder for sensing said coding means and monitoring the applicator width dimension relative to electron beam width.