CS205254B1 - Collimating device of exiter - Google Patents

Description

The invention relates to a collimator device of a feed, e.g. By collimating devices, the irradiated field sizes are defined by defining the radiation beam of the emitter.

In current irradiation devices with radioisotope-based radioactive sources, two basic elements are used to collimate the beams. They are both tubes and continuously adjustable orifice plates. The use of tubes allows the patient to be irradiated in a so-called compression manner, i.e. direct contact of the tube with the irradiated field. In this method, undesirable semi-shades do not arise around the irradiated field. The tube prevents these penins. The disadvantage of using tubes is their great weight. This places increased physical demands on the operator when changing the tubes, which need to be varied according to the desired field size and the distance of the emitter from the surface of the object to be irradiated, which is crucial for the depth dose rate.

From the operator's point of view, irradiators with adjustable orifice plates are preferable. In these irradiators, however, an undesirable semi-shade around the irradiated field arises in proportion to the distance of the radiator from the irradiated field and in proportion to the diaphragm design. Due to the necessity to maintain the appropriate distance of the emitter from the object to be irradiated, irradiators with continuously adjustable orifice plates are not suitable for compression use.

However, as has been found in the course of the invention, any assignment of the tube to the orifice plate does not satisfy the advantages of both types of irradiators. This can be achieved, in particular, under certain geometric conditions of the aperture of the aperture used and the tube.

These advantages are provided by a collimator device for adjusting the size of the irradiated fields according to the invention, which is characterized in that the orifice is associated with a tube, the orifice outlet dimension being smaller than the inlet dimension of the tube and its distance divided by its outlet dimension reduced is equal to the length of the tube divided by its outlet dimension reduced by the inlet dimension of the tube.

The collimating device according to the invention achieves a considerable reduction in the weight of the entire device compared to known tube-type irradiators and thus much easier operation. Compared to types of irradiators with orifice plates, the collimated field improves to a level equal to the use of tubes.

An exemplary embodiment of the invention is shown schematically in the accompanying drawing.

The tube 2 is arranged in a collimating relationship to the orifice 6. The alignment of the two systems must be ensured, for example, by the method of hanging the tube 2 or by adjusting the size of the irradiated field according to the size of the used tube 2. The method of hanging the tubes 2 can vary.

The aperture dimension i is always assigned a certain tube 2 of the selected dimension, which meets the following dimensional conditions:

a) D <dj

where is

L aperture length,

D aperture output dimension, d aperture input dimension,

L, tube length Dj tube outlet dimension and dj tube outlet dimension.

The application of the invention is versatile in radiators, where a precise definition of the irradiated field size is required.

Claims (1)

SUBJECT OF THE INVENTION A collimator device for adjusting the size of the irradiated fields, characterized in that a tube (2) is associated with the orifice (1), the outlet dimension (D) of the orifice (1) being smaller than the inlet dimension (d,) of the tube (2); its length (L) divided by its output dimension (D) less the input dimension: · (d) the aperture (1). is equal to the length (Lj) of the tube (2) divided by its outlet dimension (D,) minus the inlet dimension (d,) of the tube (2).