Laser thermal ablation

Combination therapy The use of local-interventional procedures is restricted to a maximum tumour size of 5 cm in diameter. Therefore, a combination of two local techniques is seen as promising. The joint application of PEI and TAB has proved its efficacy for some time. (177) Similarly, there have been reports about the successful use of TACE following laser thermal ablation. (136) Further encouraging options include a combination of TACE and RFTA, TACE with microwave coagulation (149) or TACE with cryotherapy. Using TACE, the size of the HCC can be reduced in some cases, making it possible to carry out subsequent ablation with better results. 

Dick, E.A., Joarder, R., de Jode, M., Tayior-Robinson, S.D., Thomas, H.C., Foster, G.R., Gedroyc, W.M.W. MR-guided laser thermal ablation of primary and secondary liver tumours. Clin. Radiol. 2003 58 112-120... 

Pacell C.M., Bizzari, G., Cecconi, R, Caspani, B., Magnolfi, F., BiancUni, A., Anelli, V., Pacella, S., Rossi, Z. Hepatocellular carcinoma long-term results of combined treatment with laser thermal ablation and transcatheter arterial chemoembolization. Radiology 2001 219 669-678... 

In a recently published article, Pacella et al. (2001) evaluated the safety, local effectiveness, and long-term results of laser thermal ablation (LTA) in the treatment of small hepatocellular carcinomas in 74 patients. Their study reported no major complication with an average of 1.3 sessions per tumor. Overall survival rates were 99%, 68%, and 15% at 1, 3, and 5 years, respectively. Dodd et al. (2000) also reported a median survival of 27 months and a 5-year survival rate of 26% following laser thermal ablation. The parameters that correlate with good outcome are the same as those for surgery fewer than five tumors, tumors smaller than 5 cm, slow growth rate, and no extrahepatic tumor (VoGL et al. 1998). 

Thermal ablation. The SRG is normally 7t-shifted in relation to the interference pattern, and is the result of the application of a very intense pulse of laser light or a high-power continuous wave (cw) laser. The SRGs cannot be optically erased, but rather only thermally erased. In some experiments, some polarization dependence was observed, which cannot be explained with present knowledge of the field. The dye does not need to be azobenzene for such SRGs (see Grzybowski et... 

A slight initial expansion of the film and darkening of the irradiated film surface are observed prior to ablation for both fluences (250 and 60 mj cm 2, shown in Fig. 37b). Ablation of the film starts, depending on the fluence, at a later time. The ending of the ablation process is also affected by the applied laser fluence. Ablation stops at +80 ns, which coincides almost with the end of the excitation laser pulse for 250 mj cm-2, while it continues until +140 ns for 60 mj cm 2 (Fig. 37d). The fluence-dependent ablation dynamics indicates that not only photochemical reactions but also pho-toinitiated thermal reactions are involved in the ablation process of the triazene polymer film. 

C.J. Lightdale, S.K. Heier, N.E. Marcon, et al. (1995). Photodynamic therapy with porfimer sodium versus thermal ablation therapy with Nd YAG laser for palliation of esophageal cancer a multicenter randomized trial. Gastrointest. Endoscopy, 42(6), 507-512. 

Since the first description of interstitial tumor thermal ablation using laser therapy by Sown in 1983, experimental studies have shown that a reproducible... 

In addition to DESI and AP-MALDI, a large variety of other, sometimes closely related, atmospheric-pressure desorption ionization techniques have been introduced in the past decade, connected to a huge number of acronyms. Van Beikel et al. [76] tried to classify these emerging techniques into four categories, i.e., (1) thermal desorption ionization, (2) laser desorption/ablation ionization, (3) liquid-jet and gas-jet desorption ionization, and (4) hquid extraction surface sampling probe ionization. 

Various percutaneous, locoregional therapeutic modalities have been developed and tested clinically over recent years for the treatment of HCC. These include intratumoral injection of ethanol or acetic acid and thermal ablation with RF, laser, micro-waves, or cryosurgery. Percutaneous ethanol injection (PEI), more frequently performed in the past, is considered to be effective for the treatment of relatively small-sized, encapsulated early-stage HCC and therefore may achieve 5-year survival rates of 32%-47% (Lencioni et al. 1995 Livr aghi et al. 1995). The... 

The wide range of the values of the applied energy to the metastases indicates that there is a high variance in heat distribution. Sometimes a couple of minutes are enough to treat a metastasis with a reliable safety margin and sometimes application times of 30 min and more are necessary to get the same necrosis in another metastasis of the same size. Therefore, reliable nearly online monitoring of treatment is absolutely necessary in order to avoid over- or undertreatment of the metastases. Due to the fact that laser ablation is fully compatible with MRI, which is the most reliable method for thermometry, MRI is very well suited for monitoring thermal ablation such as LITT. 

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