Radiofrequency ablation: The effect of distance and baseline temperature on thermal dose required for coagulation

Abstract

In both models, thermal dosimetry required to achieve coagulation was not constant, but current and distance dependent. Hence, other formulas for thermal dose equivalence may be needed to predict conditions for thermal ablation.

Radiofrequency ablation of small liver malignancies under magnetic resonance guidance: progress in targeting and preliminary observations with temperature monitoring

“…This is in contrast with the previously reported technique of switching between power application and imaging, which significantly lengthens the procedure [26]. Nonetheless, the clinical usefulness of thermal dose mapping remains questionable and the T2-based signal changes after application of an empirically determined dose of energy appears to be a more reliable indicator for the endpoint of RF ablation [27,28].…”

Liposomal Doxorubicin Increases Radiofrequency Ablation–induced Tumor Destruction by Increasing Cellular Oxidative and Nitrative Stress and Accelerating Apoptotic Pathways

“…In essence, we are producing an infi nite spectrum of thermal doses ( 50 ), which underscores the importance of understanding the spatial distribution of a myriad of different mechanisms of cell death and the varied physiologic responses to different levels of thermal insult. On the other hand, it can be argued that rather than resorting to a common strategy of reducing the study of hyperthermia to a single or a set of limited thermal doses ( 50,51 ), our model helps us understand what occurs across a wide range of temperatures and thermal doses, a situation which undoubtedly occurs not only in high-temperature ablation, but also more often than not for lowertemperature hyperthermia regimens ( 52 ). Regardless, our data support the contention that conceptual models such as the concentric zones highlighted in Figure 2 will be needed to best understand current and future thermal ablation paradigms.…”

“…These fi ndings also encourage exploration of combined treatment for other methods of tumor ablation. Finally, some of these modifications may be necessary for other tumor types which are likely to show both variable thermal dosimetry ( 50,51 ) and varied sensitivity to different adjuvants.…”

Hyperthermia classic commentary: ‘Arrhenius relationships from the molecule and cell to the clinic’ by William Dewey,Int. J. Hyperthermia, 10:457–483, 1994

“…Thermal dose can also be useful for thermal ablation procedures to establish safety margins and protection of sensitive tissues adjacent to the target region. It should be noted that some attempts to use the thermal isoeffect dose in describing the thermal exposure needed for tissue coagulation (ex vivo liver and muscle) have not been successful [31]. Careful work is needed to determine what the underlying differences are between these studies and others where the concepts seem to work effectively.…”