Catheter and catheter system

1. A catheter comprising:

an elongated and axially rigid catheter body which has a distal end and a proximal end in respect of an operating position, wherein a deformable protection section of the catheter body, which is provided with predetermined deformation resistance, is disposed on the distal end, and a transducer element of a converter device for converting displacement into a non-mechanical quantity is provided on a distal end of the protection section, and a corresponding pick-up element of the converter device is provided in a stationary manner on a proximal end of the protection section, wherein the catheter body comprises a lead for transmitting a measurement signal generated by the converter device to the proximal end, and a measuring connector on the proximal end, wherein the transducer element comprises a light-emitting element, and the pick-up element comprises a photodetector element, wherein a flat color filter or a polarization filter is assigned to the light-emitting element, or to the photodetector element so that location information from the non-mechanical quantity is converted into frequency information or polarization information to deduce an extent to which displacement of the protection section occurs,

wherein the light-emitting element comprises an elongated fiber-optic element guided in a spiral groove formed in an outer wall of a cylinder provided in the protection section of the catheter body, and

wherein displacement of the protection section is deduced based on a point in time a light beam signal exiting the fiber-optic element is detected by the stationary photodetector element.

2. The catheter according to claim 1 , wherein the predetermined deformation resistance is attained via natural elasticity of the protection section.

3. The catheter according to claim 1 , wherein at least three pick-up elements are evenly distributed about a longitudinal axis or a virtually extended longitudinal axis of the catheter body.

4. The catheter according to claim 3 , wherein exactly three pick-up elements are evenly distributed about the longitudinal axis with an angular separation of 120° and are assigned to exactly one transducer element.

5. The catheter according to claim 4 , wherein the exactly three pick-up elements are assigned to one pick-up system which picks up spatially resolved signals.

6. The catheter according to claim 5 , wherein the pick-up system comprises a charge-coupled device (CCD) row or CCD matrix.

7. The catheter according to claim 1 , wherein the flat color filter or the polarization filter has locally varying filter characteristics.

8. The catheter according to claim 1 , further comprising timing means assigned to the transducer or pick-up element to enable predetermined temporal control of their activation or location on a predetermined trajectory in the region of the protection section, and wherein the pick-up element is designed to pick up time resolved signals.

9. The catheter according to claim 1 , wherein the catheter is in the form of an electrode lead having at least one stimulation and/or sensing electrode.

10. A catheter system comprising:

a catheter according to claim 1 , and

a measuring unit connected to the measuring connector for determining a displacement of the protection section and/or a pressure acting thereon.