Systemkonstanz und Energieverteilung bei Laser-
induzierter interstitieller Thermotherapie (LITT)

Zusammenfassung

Ziel: Gewinnung von Daten zur Systemkonstanz und zur Energiedistribution bei Laserinduzierter Thermotherapie mit handelsüblichen Komponenten. Material/Methode: Durchführung von Konstanzprüfungen optischer Kupplungen, Lasergeneratoren und Laserfasern der Firmen Dornier (Germering, Deutschland), Hüttinger (Umkirch, Deutschland) und Somatex (Berlin, Deutschland) über 60 Minuten mit 25 Watt unter sequenzieller Verwendung zweier Lasertestgeräte (MY-Test, Hüttinger). Je zwei In-vitro-Ablationen in Rinderleber mit Laserfasern Mikrodom-Applikator Typ A13-0540, Microflexx-Applikator REF A13-0561 (beide Hüttinger) Diffusor-Tip H-6111-T3, Diffusor-Tip H-6111-T4 (beide Dornier), Somaflex-Diffuser (Somatex) über 20 Minuten mit 25 Watt und Bestimmung der Koagulationsgeometrien. Ergebnisse: Die unterschiedlichen Systemkomponenten wiesen über den zeitlichen Verlauf Divergenzen auf, die 10 % nicht überschritten. Einzelne Systemkomponenten zeigten sich entgegen Herstellerempfehlungen inkompatibel. Signifikante Unterschiede wiesen die Abstrahleigenschaften der Laserfasern insbesondere in der axialen, vorwärts weisenden Ausrichtung auf. Schlussfolgerung: Die Kenntnis der Emissionsleistung des Lasersystems sowie der individuellen Abstrahlcharakteristiken der Laserfasern ist für den Ablationserfolg bei der LITT entscheidend.

Abstract

Purpose: Evaluation of the continuity and energy distribution of a laser system for laser-induced thermo therapy. Material and Methods: For evaluation of the continuity of laser optical devices, laser generating units and optical fibers of three different manufactures (Dornier, Hüttinger, Somatex), we used the equipment to generate a laser beam of 25 Watt for 60 minutes. Measurements of the applied energy were done sequentially with two MY Test (Fa. Hüttinger) units. We also performed two in vitro ablations of animal liver tissue with different fiber optics [Mikrodom A 13-0540, Microflexx REF A 13-0561 (Hüttinger), Diffusor-Tip H-6111-T 3, Diffusor H-6111-T 4 (Dornier), Somaflex-Diffusor (Somatex)] over 20 minutes at- an energy flow of 25 J per second. We then evaluated the geometry of coagulation. Results: The different equipment used for our tests showed differences of a maximum of 10 %. Some components did not work properly in certain configurations even though the manufacturer assured it would. We saw significant differences in the ablation characteristics of the different fiber optics, especially in axial and frontal directions. Conclusion: Knowledge of the different characteristics in energy distribution and ablation characteristics are an important factor in performing a successful laser-induced thermo therapy.

Schlüsselwörter

LITT - Lebermetastasen - Qualitätssicherung - Laser

Key words

LITT - Liver neoplasms - Quality - Laser

Literatur

• 1 Vogl T J, Weinhold N, Muller P, Phillip C, Roggan A, Mack M G, Balzer J O, Eichstadt H, Blumhardt G, Lobeck H, Felix R. Early clinical experiences with MR-guided laser-induced thermotherapy (LITT) of liver metastases in preoperative care.  Fortschr Röntgenstr. 1996;  164 (5) 413-421
• 2 Muralidharan V, Christophi C. Interstitial laser thermotherapy in the treatment of colorectal liver metastases.  J Surg Oncol. 2001;  76 73-81
• 3 Albrecht D, Germer C T, Roggan A, Isbert C, Ritz J P, Buhr H J. Laserinduzierte Thermotherapie - Technische Voraussetzungen zur Behandlung maligner Lebertumoren.  Chirurg. 1998;  69 930-937
• 4 Germer C T, Albrecht D, Boese-Landgraf J, Roggan A, Isbert C. Laser-induced thermotherapy (LITT) in the treatment of colorectal liver metastases - A clinical pilot study. In: Mülller G, Roggan A (eds) Laser-induced Interstitial Thermotherapy. Bellingham; SPIE Press 1995: 393-399
• 5 Germer C T, Albrecht D, Roggan A, Isbert C, Buhr H J. Experimental study of laparoscopic laser-induced thermotherapy of liver tumors.  Br J Surch. 1997;  84 317-320
• 6 Jolesz F A, Zientara G P. MRI-guided Laser-induced Interstitial Thermotherapy: Basic principles. In: Müller G, Roggan A (eds) Laser-induced Interstitial Thermotherapy. Bellingham; SPIE Press 1995: 294-324
• 7 Vogl T J, Müller P K, Hammerstingl R, Wienhold N, Mack M G, Philipp C, Deimling M, Beuthan J, Pegios W, Riess H. et al . Malignant liver tumors treated with MR imaging-guided laserinduced thermotherapy: technique and prospective results.  Radiology. 1995;  196 257-265
• 8 Vogl T J, Mack M, Straub R, Eichler K, Engelmann K, Roggan A, Zagnos S. Percutaneous interstitial thermotherapy of malignant liver tumors.  Fortschr Röntgenstr. 2000;  172 12-22
• 9 Vogl T J. Verification of MR-Thermometrie.  Fortschr Röntgenstr. 1998;  169 (2) 182-188
• 10 Gewiese B, Beuthan J, Fobbe F, Stiller D, Müller G, Boese-Landgraf J, Wolf K J, Deimling M. Magnetic resonance imaging-controlled laser-induced interstitial thermotherapy.  Invest Radiol. 1994;  29 345-351
• 11 Vogl T J, Assal J, Philipp C, Rohde E, Fischer P, Boettcher H, Gremmler M, Roggan A, Geimling K, Felix R. Nichtinvasives Temperaturmonitoring für die interventionelle laserinduzierte Thermotherapie von Lebermetastasen.  Zentralbl Radiol. 1994;  150 1-3
• 12 Vogl T J, Mack M G, Straub R, Roggan A, Felix R. MRI-guided abdominal interventional radiology: laser-induced thermotherapy of liver metastases.  Endoscopy. 1997;  29 577-583
• 13 Roberts H RS, Paley M, Sams V R, Wilkinson I D, Lees W R, Hall-Graggs M A, Bown S G. Magnetic Resonance Imaging control of laser destruction of hepatic metastases: correlation with post-operative helical CT.  Min Invas Ther & Allied Technol. 1997;  6 53-64
• 14 Vogl T J, Eichler K, Straub R, Engelmann K, Zangos S, Woitaschek D, Bottger M, Mack M G. Laser-induced thermotherapy of malignant liver tumors: general principals, equipment(s), procedure(s)-side effects, complications and results.  Eur J Ultrasound. 2001;  13 (2) 117-127
• 15 Urban P, Philipp C, Frommeld T, Berlien H-P. Possibilities and limitations of the ultrasound guided laser induced thermotherapy (LITT) of malignant liver processes. 13th Biennial Meeting of the Deutsche Gesellschaft für Lasermedizin 2001
• 16 Moller P H, Hannesson P H, Invarsson K, Olsrud J, Stenram U, Tranberg K G. Interstitial laser thermotherapy in pig liver: effect of inflow occlusion on extent of necrosis and ultrasound image.  Hepatogastroenterology. 1997;  44 (17) 1302-1311
• 17 Soyer P, Mosnier H, Choti M A, Rymer R. Intraoperative and laparoscopic sonography of the liver.  Eur Radiol. 1997;  7 (8) 1296-1302
• 18 Germer C T, Albrecht D, Roggan A, Buhr H J. Technology for in situ ablation by laparoscopic and image-guided interstitial laser hyperthermia.  Semin Laparosc Surg. 1998;  5 (3) 195-203
• 19 Vogl T J, Mack M G, Roggan A, Straub R, Eichler K C, Müller P K, Knapp V, Felix R. Internal cooled power laser for MR-guided interstitial laser-induced thermotherapy of liver lesions: initial clinical results.  Radiology. 1998;  209 381-385
• 20 Bremer C, Alikemper T, Menzel J, Sulkowski U, Rummeny E, Reimer P. Preliminary clinical experience with laser-induced interstitial thermotherapy in patients with hepatocellular carcinoma.  Magn Reson Imaging. 1998;  8 235-239
• 21 Germer C T, Isbert C, Albrecht D, Roggan A, Pelz J, Ritz J P, Müller G, Buhr H J. Laser-induced thermotherapy combined with hepatic arterial embolization in the treatment of liver tumors in a rat tumor model.  Ann Surg. 1999;  320 55-62
• 22 Albrecht D, Germer C T, Isbert C, Ritz J P, Roggan A, Mueller G, Buhr H J. Interstitial laser coagulation: evaluation of the effect of normal blood perfusion and the application mode on lesion size.  Lasers Surg Med. 1998;  23 40-47
• 23 Wacher F K, Reither K, Ritz J P, Roggan A, Germer C T, Wolf K J. MR-guided interstitial laser-induced thermotherapy of hepatic metastasis combined with arterial blood flow reduction: Technique and first clinical results in an open MR system.  J Magn Reson Imaging. 2001;  13 31-36