Verfahren und Vorrichtung zur Regelung einer gezielten Waermedeponierung in ein Material

Beschrieben wird ein Verfahren sowie eine Vorrichtung zur Regelung einer gezielten Waermedeponierung in ein Material, vorzugsweise in biologisches Gewebe, mit einer Ultraschallwellen erzeugenden Einheit, die Ultraschallwellen in das Material einkoppelt, einer Ultraschallwellen detektierenden Einheit, die die aus dem Material austretenden Ultraschallwellen detektiert und einer Auswerteeinheit, die auf der Grundlage der detektierten Ultraschallwellen Aussageparameter generiert, die ueber die thermischen und strukturellen Aenderungen innerhalb des Materials Aufschluss geben. Die Erfindung zeichnet sich dadurch aus, dass die aus dem Material austretenden Ultraschallwellen zeit- bzw. ortsaufgeloest detektiert werden, dass in der Auswerteeinheit die detektierten Ultraschallwellen zeitlich aufgeloest und nach dem Grad ihrer Laufzeitaenderung relativ zu den Ultraschallwellensignalen, die von detektierten Ultraschallwellen herruehren, die am Material vor der Waermedeponierung reflektiert worden sind, untersucht werden und als Grundlage fuer eine raeumliche Abgrenzung von sich, im Wege des Waermeeintrages einstellenden strukturellen Aenderungen innerhalb des Materials verwendet werden, und dass unter Zugrundelegung eines Behandlungsziels im Material sowie der ermittelten strukturellen Aenderungen im Material ein zur Waermedeponierung erforderlicher Energieeintrag pro Zeit in das Material geregelt wird.

WO 200024468 A UPAB: 20000630 NOVELTY - To control targeted heat deposit in material, especially biological tissue, the heat is applied by ultrasonics and a detector registers ultrasonic waves emerging from the material by time or location. An evaluation unit assesses the detected ultrasonic wave leakage and the rate of change over time against ultrasonic wave reflection from the material, before heat is deposited, to show the structural changes within the material. The energy directed at the material, by time, is set according to the structural material changes and the objective of the therapy. DETAILED DESCRIPTION - The reflected ultrasonic waves from the material are caught by a spectral action, and are integrated over the whole frequency range. The time change of the integral value is monitored and, on a deviation from a starting integral, the value derived before material heating is taken as a starting parameter for the formation of gas bubbles within the material. At the start of heat deposition, the start integral is established at a known temp. within the tissue material, as a reference value to register deviations in the integral behavior. After changes in the integral behavior have faded, a parameter is derived for a condition before the biological tissue starts to carbonize internally. At the evaluation unit, the detected ultrasonic waves are converted into a window pattern for each ultrasonic pulse, in a dynamic match against time. The start of each separate window section is in a fixed relationship to the signal development of the detected ultrasonic waves. A direct or indirect spectral comparison is made for each current window section with a previous window section by time, using the same signal development for the same start of the window section. The spectral comparison gives an estimate of the behavior of the coefficient of attenuation by time of the reflected ultrasonic waves corresponding with the detected signals in the separate window sections. The timed behavior of the attenuation coefficients is taken as the basis for the zonal limit of the structural change within the tissue set by the heat delivery, for control of the energy delivered over time to deposit heat in the tissue. The spectral comparison in the time or frequency range forms differences in the spectral field or establishes spectral shifts. The ultrasonic wave monitor is positioned to receive only ultrasonic waves reflected or scattered from the tissue material. The heat is deposited in the biological tissue by targeted radiation of electromagnetic rays, and preferably laser light or by the application of an electrical alternating field or an ultrasonic wave field. An INDEPENDENT CLAIM is included for an apparatus where the ultrasonic wave generator and detector are positioned to cover the same zone, with adjustment in relation to the tissue material being treated. The heat deposit unit is central to the ultrasonic wave generation and detection units, aligned at the tissue material. Preferred Features: The generating and detecting units are positioned on the periphery of a spherical plane, to focus the ultrasonic waves on the tissue. The assembly is contained within a housing (G), placed directly or indirectly on the tissue material, to give a set gap for the transmitter and receiver units, which are in a flat or linear array. The unit to deposit heat is a glass fiber (3), to carry the laser light directly to the tissue material (4) from the ultrasonic converter (1). USE - As diagnostic instrument, using ultrasonics to raise the temperature within the tissue area especially for the treatment of tumors and metastasis. It can also be used in the treatment of glaucoma. ADVANTAGE - Apparatus enables effective destruction of targeted tissue cell areas, with minimum damage to surrounding tissue.