The present invention relates to apparatus and methods for the therapeutic application of ionizing radiation as for example treatment of stenosis in coronary vessels, and in cancer therapy. In particular it relates to a guide wire assembly having an integrated ultra miniature radiation source.
The generation of X-rays are commonly achieved by employing X-ray tubes. However, this type of device is expensive, in particular when it is to be adapted for use in very small volumes, i.e. when it is necessary to miniaturize the device substantially.
A much simpler way of manufacturing very small X-ray generating devices is to base the manufacture on chip technology. However, this approach will yield essentially flat devices emitting radiation basically in one direction, at least they will not be capable of emitting isotropic radiation.
In our International Patent Application WO 98/36796 (with priority from pending U.S. application Ser. No. 08/805,296) there is disclosed a miniaturized radiation source which can be energized and de-energized at the site of therapy inside the body at the location of e.g., a tumor to be treated. The radiation source is preferably mounted on a guide wire or a catheter assembly, so as to be easily insertable in the body of a cancer patient.
In WO 97/07740 there is disclosed an X-ray catheter which is said to be usable for irradiation of the site of an angioplasty procedure to prevent restenosis and other conditions in any vessel, lumen or cavity of the body. The device disclosed therein cannot be batch manufactured in the same way as a X-ray emitting chip according to the invention which is the subject matter of the present application, but it irradiates evenly, i.e isotropically.
However, this may also be a disadvantage in the sense that also healthy tissue may become irradiated.
Thus, it would be desirable to have access to a device for providing ionizing radiation to a therapy location having better efficiency, in terms of capability to irradiate larger areas of the tissue to be treated, in particular to be able to deliver essentially isotropic radiation. It would also be desirable to be able to control the intensity distribution over the damaged or malignous tissue.
Therefore, it is an object of the present invention to provide a device that meets the above requirements and that does not exhibit the drawbacks associated with the prior art devices.
This object is achieved with a device as defined in claim 1, namely with a device for providing ionizing radiation at a therapy location inside a living body, comprising a core member; a flexible support member provided on the surface of said core member; a plurality of miniaturized sources of ionizing radiation attached to said flexible support member; and coupling means for coupling said sources of ionizing radiation to an external power source.
By using a number of X-ray sources together with a selective control for each source, the radiation may be controlled so that it only radiates in selected directions. Thereby it is possible to selectively irradiate desired parts of a vessel or malignous tissue according to the clinical need.
In this way, the individual sources will each contribute to the radiation so as to create an essentially isotropic radiation source. Alternatively, by selectively activating one or more chips, it will be possible to irradiate the parts of the tissue that are malignous thereby avoiding irradiating healthy tissue.
The invention will now be described with reference to the attached drawings.