Laserinduzierte Thermotherapie Technische Voraussetzungen zur Behandlung maligner Lebertumoren

Abstract

Laser-induced thermotherapy is an in situ ablation method for the local treatment of liver tumors. The basic prerequisite for induction of adequate treatment volumes for clinical use was the development of a thermostable application system. In an ex vivo test series, the specially developed application system (diffuser tip) with 5760 J had a higher thermic loading capacity than the Ringmode applicator with 4200 J, thus enabling the induction of significantly larger lesions with a volume of 7.6 cm3. The results of a further in vivo test series demonstrated that the lesions were subject to a four-phase connective-tissue organization within a 6-month period. Furthermore, the same laser energy (4200 J) was associated with a significantly lower lesion volume of 2.5 cm3 in the in vivo than in the ex vivo test series. The influence of liver perfusion on the inducible lesion volume was examined in a further animal experimental study. By temporarily interrupting hepatic blood perfusion (Pringle's maneuver) during laser application, the effective volume could be increased to 50.3 cm3 (P < 0.01) using an optical beam splitter. These results show that the technical prerequisites for reliable clinical application of laser-induced thermotherapy have been fulfilled.

Percutaneous laser ablation for benign thyroid nodules: a meta-analysis

“…In principle, PLA can lead to irreversible cell damage and the formation of thermal coagulation necrosis with high temperatures through directly transmitting laser light into the target tissue via flexible fibers [ 44 , 45 ]. The clinical effectiveness of PLA in reducing the TN volume was evaluated by performing ex vivo and in vivo studies in animals [ 46 , 47 ] as well as numerous clinical studies [ 25 – 43 ]; however, previous research had the drawback of uniform follow-up intervals.…”

Colorectal tumors and hepatic metastases differ in their optical properties—relevance for dosimetry in laser-induced interstitial thermotherapy

“…Thus, the treatment parameters must be adapted during the lasering procedure as a result of the changes caused by thermal coagulation. Laser power should be reduced with increasing application times to prevent overheating of the tissue with a lower optical penetration depth after coagulation [40].…”

In vivo laser‐induced interstitial thermotherapy of pig liver with a temperature‐controlled diode laser and MRI correlation

“…This result however re¯ects the size of the coagulation zone immediately after treatment, while late data in other experiments [17±19] showed a decrease of the coagulation volume over time after an initial increase in lesion volume within 24 hours. The Diode laser system used in our study was less effective in terms of energy deposition in the depth of the liver tissue and resulted in smaller lesions than the established Nd:YAG lasers [8,20]. One reason for this may be the lower optical penetration depth of the used wave length (805 nm) in liver tissue [15].…”

“…This leads to an increase in the effect of LITT [9±13]. The already clinically established temperature controlled Nd:YAG laser systems consist of a fragile glass dome surrounding the ®ber tip [8,16] and use relatively large diameters of 3.0 mm [13] which limits the use via a percutaneous approach. The diffuser tip used in our study however, has an outer diameter of 1.8 mm and the ®ber has a high mechanical and thermal load capacity, which permits the use over a small 12 G coaxial system for a percutaneous puncture allowing the procedure to be performed completely under MRI guidance.…”