Track ablation

Nevertheless, based on the principle of cauterization, the coagulative potential of the thermal ablation procedure itself makes the bleeding of a treated lesion quite unusual. To avoid needle track bleeding it is recommended to perform hot probe repositioning and removal (i.e. needle track ablation). Therefore, regarding the present literature bleeding in total is a rare, in most cases self-limiting, complication with a frequency of no more than 2%. 

Fig. 5.1.9a-c. Hemorrhage and cavitation during RFA. a Two metastases of colorectal carcinoma (CRC) in the LLL b start of RFA of the medially located metastasis c hemorrhage upon further hook deployment and cavitation post track ablation... 

The application of ion beams to polymers has been worthy of remark in the fields of advanced science and technology since the radiation effects of ion beams on polymers are different from those of conventional radiation such as electron beams and gamma-rays. The effects of ion beams are called LET effects but the detailed mechanisms of these effects on polymers have not been elucidated so far. So-called high density excitation effects such as carbonization, blackening, ablation and formation of nuclear tracks, which only occur at high densities, have been studied by a number of advanced spectroscopic methods. 

Rauch, S., Morrison, G.M., Moldovan, M. Scanning laser ablation-ICP-MS tracking of platinum group elements in urban particles. Sci. Total Environ. 286, 243-251 (2002)... 

Baseline TDR measurements were made for two samples in their entirety and then the two samples were ablated. In one case a laser was used to make a cut perpendicular to the direction of the track formed by the dielectric seal material. In the second sample, a dicing saw was used to cut through the top plate of the sample and remove a portion of the dielectric seal. After the samples were ablated, a second set of TDR measurements were made for comparison with the baseline. In both cases, there were no visible differences between the baseline and the second measurement. 

Silicone laminates are useful from cryogenic temperatures to about 260°C. The dielectric properties of silicones are particularly useful. Both dissipation factor and dielectric constant are low at room temperature and remain relatively constant up to 150°C. Because of the presence of the silicon atom, silicone laminates have good arc- and track resistance. The physical properties of silicones are not greatly influenced by aging, but compared with laminates that are based on other resins, the flexural and tensile strengths of silicones are not unusually high. Silicone laminates are used in electronics, heaters, rocket components, slot wedges, ablation shields, coil forms, and terminal board. 

Future advances include the automation of registration, which could further streamline clinical translation of such technologies. Miniaturization of internalized sensors for electromagnetic tracking of needles and ablation probes will have the ability to transform image-guided needle-based procedures by providing real-time multimodality feedback. 

Hoffmann, D.L., Paterson, B.A., Jonckheere, R. (2008) Measurements of the uranium concentration and distribution in a fossil equid tooth using fission tracks, TIMS and laser ablation ICPMS implications for ESR dating. Radiation Measurements, 43, 5-13. 

The use of laser ablation (LA)-ICP-MS is of particular interest for this type of application, because the analysis of small particles that have been transported in aerosol form provides a powerful method for tracking down nuclear activities. Therefore, the analysis of so-called hot particles (originating from nuclear weapons tests, accidental releases, or unauthorized activities) is of great importance. 

In larger lesions, the array is withdrawn and redeployed anteriorly at 1.5- to 2.0-cm intervals into the tumor. After the hooks are fully deployed, the electrode is connected to the RF generator. The heating protocol for all the available needles is provided by the manufacturer. In general, the generator is started at a lower power setting and is subsequently increased in 10-W increments at 1-min intervals. The endpoint of RF application is the appearance of a rapid increase in tissue impedance (Roll-off) around the electrode. When this occurs, the RF application is automatically terminated. This process is repeated starting at 70% of the roll-off power until a second increase of the impedance occurs. Since the time point of the rapid increase in tissue impedance cannot be predicted, the ablation time needed varies dramatically between different tumor sizes and nodules. At the end of the procedure the needle track is ablated to prevent any tumor dissemination. Therefore, the tip has to be unisolated prior to the insertion of the needle. 

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