GB2331360A

GB2331360A - Positioning a patient on an adjustable table

Info

Publication number: GB2331360A
Application number: GB9823632A
Authority: GB
Inventors: Armin Rockseisen
Original assignee: LAP GmbH
Current assignee: LAP GmbH
Priority date: 1997-11-12
Filing date: 1998-10-28
Publication date: 1999-05-19
Anticipated expiration: 2018-10-28
Also published as: GB2331360A9; DE19750004B4; FR2770763B1; GB9823632D0; GB2331360B; FR2770763A1; DE19750004A1

Abstract

A device for positioning a patient on an adjustable table comprises a laser apparatus (1, 8) which projects lines in two or more planes, forming a cross. The lines extend through the isocentre of a diagnostic apparatus or an irradiation apparatus. Sensors (4, 5) are allocated to each line produced by the laser apparatus are able to detect the light planes (9, 10) which form the light lines. The senors may detect light reflected from a reflector or mirror. Alternatively, the sensors may detect light from a similar laser apparatus placed opposite. A monitoring device signals when a sensor no longer responds.

Description

2331360 A DEVICE FOR POSITIONING A PATIENT ON AN ADJUSTABLE UNDERLAY The

invention relates to a device for positioning a patient on an adjustable underlay, according to the introductory part of patent claim 1.

In nuclear medicine with radiologic diagnosis and in irradiation therapy it is a question of aligning the patient reproducably accurately and quickly so that the diseased organ may be examined with the greatest precision or impinged with irradiation. Furthermore there may arise the necessity of having to treat patients in the same position with different machines.

The patient is usually held by an adjustable underlay, for example a table which can be adjusted along three orthogonal axes. The irradiation source of an irradiation apparatus is usually focussed onto a certain point in a room. As known irradiation apparatus produce a pivoting movement of the irradiation source, whose axis runs through the focus of the irradiation source (isocentre). With the aligninent of the patient with regard to the irradiation apparatus it is a question of bringing the section of the body to be examined or to be irradiated into the focus or the isocentre. By computer tomography or another diagnostic method it is possible to geometrically deterniine the section to be irradiated with regard to the body of the patient. Before the patient is subjected to a suitable irradiation therapy in a so-called stimulation which comprises the same means as the irradiation device but does not contain an irradiation source, a precise aligninent is made. After an effected alignment on the patient there are deposited markings. These must be covered with lines or crosses which are projected by laser apparatus into the room. A patient who e.g. is provided with a colour marking may then by way of laser lines which are imaged on the body be aligned three dimensionally. This is effected by a suitable adjustment of the table. From DE 44 18 216 AI it is also known for aligning the patient to attach so-called retroreflectors on the patient body for example with the help of a surgical plaster. The reflectors have a distance from the isocentre which is rigidly or randomly selected. They consequently do not prevent the desired irradiation of the body part. The light coming from the laser apparatus is thrown back by the retroreflectors and received by suitable sensors. In this manner it may automatically be determined whether the patient is correctly aligned.

Laser apparatus for positioning and marking patients are also known from DE 44 21 315 or DE 44 21316.

The laser apparatus normally use so-called line lasers wherein two line lasers whose light planes intersect may project a cross. Thus in one room normally an arrangement of three laser apparatus is provided of which two lie opposite one another and Mi each case laterally project a cross onto the patient body. A third laser apparatus is located above the table and normally produces only one line (sagittal) which rims through the isocentre. Before the positioning may commence a suitable trinuning of the laser apparatus or of the laser sources must be effected so that the light planes produced by them extend through the isocentre. By way of certain influences the correct setting of the laser may be lost. It is therefore necessary to check the correct position of the light planes of the lasers since the correct situation of the patient and thus the irradiation success depends to a great extent on the precise indication of the isocentre. The checking of the correct positioning of the laser apparatus is however annoying and time consuming.

It is therefore the object of the invention to provide a device for positioning a patient on an adjustable underlay with which the trimming of the laser apparatus is continuously and automatically checked.

This object is achieved by the features of patent claim 1.

With the invention the laser apparatus are equipped with sensors which with laser apparatus arranged opposite with coincident light planes are met by the light of the respective oppositely lying laser. As long as this is the case the positionally correct position of the laser apparatus may be taken to be given. If the sensors no longer respond a suitable signal is produced so that a corresponding renewed trimming may be carried out.

The sensors in one formation of the invention are preferably integrated into the laser apparatus. They may also be installed into a separate monitoring apparatus, in particular when the monitoring is to be introduced in an already installed laser arrangement. As sensors pointlike light-sensitive elements are considered, such as individual photo diodes, difference photodiodes etc. Alternatively line sensors may also be used which function in an analog or digital manner.

The sensors are preferably mechanically coupled with the construction of the laser optics so that they automatically follow the trimming. When producing a light beam cross they are flush e.g. with the emitted light beam in both axes of the cross.

The invention is hereinafter described in more detail by way of one embodiment example.

The single figure shows a laser arrangement as it is e.g. arranged laterally of the body of a patient.

The laser apparatus 1, 8 lie opposite one another and with a first line laser 3 produce a light plane in the horizontal alignment and with the laser 2 a light plane in the vertical alignment. The same applies for the laser apparatus 8 with which the horizontal plane Is indicated at 9 and the vertical plane is indicated at 10, by which means line 6 or 7 are produced. As mentioned the light planes of the line lasers 2, 3 of both laser apparatus 1, 8 coincide. The cross projected by them corresponds to the isocentre of the irradiation apparatus which is not shown and onto which the location of the patient to be irradiated is to be aligned.

As can be recognized in the laser apparatus there is an-anged a sensor 4 on the line 7 and a further sensor 5 on the line 6. They may be point sensors. They are continuously activated on account of continuous irradiation. If however a wrong alignment of the line lasers 2, 3 or of the apparatus 1, 8 occurs, one or both sensors 4, 5 are no longer irradiated so that a change in signal occurs which can be acquired so that a renewed trimming can be carried out.

If additionally or alternatively a single laser apparatus is provided, for example for producing a sagittal line, then on the table which is not shown and on which the patient comes to lie a reflector may be attached so that a sensor for example the sensor 4 'm the laser apparatus ascertains whether the line produced by the laser apparatus goes through the isocentre.

The laser apparatus or lasers may be servo-actuated in order automatically to carry out an automatic trimming of the laser planes or the light planes in accordance with the signal of the monitoring device.

Claims

1. A device for positioning a patient on an adjustable underlay, with laser apparatus mounted in a room, which in two or more planes project lines or crosses which extend through the isocentre of a diagnosis or irradiation apparatus, wherein a sensor (4, 5) is allocated to each line produced by the laser apparatus (1, 8) with a line laser (2, 3), the sensor detecting the light plane (9, 10) of the fight of the line laser thrown back by a reflector arranged in the room or the light plane of an opposite line laser when the first and/or second line laser h"c a prior set position, and the sensor is connected to a monitoring device for the purpose of producing a signal when a sensor (4, 5) no longer responds.

2. A device according to claim 1, wherein the sensors (4, 5) are integrated into the laser apparatus (1, 8).

3. A device according to claim 1 or 2, wherein point-like or line sensors are provided.

4. A device according to one of the claims 1 to 3, wherein the sensors (4, 5) are mechanically coupled to the construction of the laser optics.

5. A device according to one of claims 1 to 4, wherein the line laser is adjustably mounted and is drivable by a motor-driven adjusting device and a control device for the drive motor of the adjusting device is controlled by the signal of the monitoring device.