Displacement detecting element

• US 20030183788A1
• Filed: 05/27/2003
• Published: 10/02/2003
• Est. Priority Date: 09/13/2000
• Status: Active Grant

• Current Assignee: Deutsches Krebsforschungszentrum Stiftung Des Oeffentlichen Rechts
• Original Assignee: Deutsches Krebsforschungszentrum Stiftung Des Oeffentlichen Rechts
• Inventors: Echner, Gernot, Schlegel, Wolfgang, Pastyr, Otto
• Granted Patent: US 6,696,694 B2
• Time in Patent Office: Days
• US Class Current: 250/505.1
• CPC Class Codes: A61N 5/1042 with spatial modulation of the radiation beam within the treatment head
• CPC Class Codes: G01B 7/003 for measuring position, not involving coordinate determination coordinate measuring G01B7/004
• CPC Class Codes: G21K 1/046 varying the contour of the field, e.g. multileaf collimators
• CPC Class Codes: H01C 10/38 the contact moving along a straight path

Abstract

The invention relates to a displacement-detecting element (1) comprising a measuring resistance (2), voltage source (3) and a displacement-dependent voltage pick off (4). The measuring resistance (2) is embodied in the form of a strip. The length of the resistor (6) corresponds to at least the maximal length of displacement (7) of the component to be detected. The invention also relates to a multileaf collimator (23) having such a displacement-detecting element (1). The aim of the invention is to produce a displacement-detecting element (a) for detecting the position of the leaves (22) in a multileaf collimator (23) in a precise and faultless manner. The displacement detecting element (1) is designed for detecting the displacement (7′) of the leaves (22) in a multileaf collimator (23) in the following manner: the measuring resistance (2) or the voltage pick off point (4) are connected in a rigid manner to the leaves (22) in order to detect the displacement and another functioning element (4 or 2) is arranged in a fixed manner. At least one of these functioning elements (2, 4) is disposed in an area (33, 33′, 33″) of the leaves (22), which is not exposed to main radiation (34).

Claims

1. Displacement detecting element (1) comprising a measuring resistance (2), a voltage source (3) and a displacement-dependent voltage pick-off (4) wherein the measuring resistance (2) is in the form of a strip and this resistance strip (6) is at least as long as the maximum length of displacement (7) of the structural component to be detected, characterized in that

the displacement detection element (1) is designed for detecting displacement (7′

) of leaves (22) of a multi-leaf collimator (23) in that the measuring resistance (2) or the voltage pick-off (4) is rigidly connected to the leaf (22) to be detected and the other functional element (4 or 2) is fixed and at least these functional elements (2, 4) are disposed in a region (33, 33′

, 33″

) of the leaves (22) which is not subjected to the main radiation (34).

2. Displacement detecting element according to claim 1, characterized in that it is directly connected to the leaves (22).

3. Displacement detecting element according to claim 1 or 2, characterized in that the electrical functional elements (2, 4, 13, 15, 16) are disposed on the side (35) of the leaves (22) facing away from radiation.

4. Displacement detecting element according to claim 1 or 2, characterized in that the electrical functional elements (2, 4, 13, 15, 16) are disposed in the rear region (33, 33′

) of the leaves (22) which is not subjected to the main radiation (34).

5. Displacement detecting element according to claim 4, characterized in that the region (33, 33′

) is the region (33, 33′

) which is shielded by a pre-collimator (36).

6. Displacement detecting element according to any one of the claims 1 through 5, characterized in that it is balanced (8) through partial removal of material from the measuring resistance (2) formed as resistance strip (6).

7. Displacement detecting element according to any one of the claims 1 through 6, characterized in that it has a housing (9), which can be mounted to a leaf (22).

8. Displacement detecting element according to claim 7, characterized in that the housing (9) is inserted into a recess (37) of the leaf (22).

9. Displacement detecting element according to claim 7 or 8, characterized in that the housing (9) defines a recess (10) which extends along its length and in which a fixed tongue (11) is displaceably disposed, wherein the amount of displaceability corresponds to at least the maximum length of the displacement (7) and one of the functional elements (4 or 2) is associated with the housing (9) and the other with the tongue (11).

10. Displacement detecting element according to claim 9, characterized in that the electrical functional elements (13, 2 or 15, 16) which have at least the maximum length of displacement (7) are located in a gap (29) between housing (9) and tongue (11).

11. Displacement detecting element according to any one of the claims 7 through 10, characterized in that the strip (6) of the measuring resistance (2) is disposed on the tongue (11) and the voltage pick-off (4) is disposed on the housing (9).

12. Displacement detecting element according to claim 11, characterized in that the voltage pick-off (4) is effected via a window (21) of the housing (9).

13. Displacement detecting element according to claim 9, 10, 11, or 12, characterized in that the housing (9) and the tongue (11) are formed as flat plastic parts.

14. Displacement detecting element according to any one of the claims 1 through 13, characterized in that the measuring resistance (2) is connected to the voltage source (3) in that a terminal (12) is disposed at one end of the resistance strip (6) and the other end communicates with a conductor path (13) which is disposed parallel to the resistance strip (6) and is connected to the other terminal (14) of the voltage source (3).

15. Displacement detecting element according to claim 14, characterized in that the resistance strip (6) and the conductor path (13) are disposed on the tongue (11) with the resistance strip (6) being formed as a first slide contact path (15), and a second slide contact path (16) being disposed parallel thereto comprising a terminal (17), wherein the voltage is picked off (4) with two electrically connected wipers (18 and 19) disposed on the housing (9) which slide along the slide contact paths (15 and 16) and with a means (5) for converting the signal into displacement information, connected between the terminals (17 and 14 or 12) of the second slide contact path (14) and the voltage source (3).

16. Displacement detecting element according to claim 12 and 15, characterized in that the wipers (18 and 19) are disposed on the outer side of the housing (9) and slide on the slide contact paths (15 and 16) by passing through a window (21) of the housing (9).

17. Displacement detecting element according to claim 15 or 16, characterized in that the means (5) for converting the signal into displacement information is a voltage meter calibrated to the displacement (7, 7′

) to be detected which picks off the measuring voltage on a resistor (20) connected between the terminal (17) and one of the terminals (12 or 14) of the voltage source (3).

18. Displacement detecting element according to any one of the claims 7 through 17, characterized in that the housing (9) has a shielding conducting layer (26) on its outer side.

19. Displacement detecting element according to any one of the claims 7 through 18, characterized in that the housing (9) is provided with a dove-tailed outer contour (31) for mounting to the leaves (22), wherein the leaves (22) have a complementary recess (32) for insertion therein.

20. Multi-leaf collimator (23) comprising displacement detecting elements according to any one of the claims 1 through 19, characterized in that each leaf (22) has at least one displacement detecting element (1) and all displacement detecting elements (1) can be connected to the control of the multi-leaf collimator (23).