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structures within into killing cancer cells, in general with minimal damage to normal tis-
sues (Hildebrandt et al., 2002; Van der Zee, 2002). The precise mechanisms by which cells
aredestroyedby heatingare yetto beelucidated(Lepock, 2003), butitissuggested that
thermal injury and the reduction in the cell growth rate may increase with temperature
up to some critical threshold, above which growth is sharply inhibited, and necrosis may
occur. Itisthoughtthatcellular necrosisisproduced by the thermal denaturation of critical
targets in the cell (Miles, 2006), and cytotoxicity, radiosensitization, and thermotolerance
responses that occur in the hyperthermic region are most likely temperature-induced
alterations in the molecular pathways (Lepock, 2005).
Hyperthermia methods may be either regional (RH) or local (LH). RH aims parts of
the body (e.g., organ, limb, or body cavity), anditisusually combined with chemother-
apy or radiation therapy. RH methods include: regional perfusion (RP) or isolation perfu-
sion (IP), continuous hyperthermic peritoneal perfusion (CHPP), also called hyperthermic
intraperitoneal chemotherapy (HIPEC), and deep tissue hyperthermia (DTH).
In RP (or IP) the blood in that part of the body is heated outside the body, and che-
motherapy can be added in at the same time. For CHPP (or HIPEC), during surgery,
heated anticancer drugs flow from a warming device through the peritoneal cavity, whose

temperature raises from 41 Cto42 C. The DTH uses devices, which are positioned on
thesurface of the bodycavityororgan to deliverRForMWpower to heat the ROI.
Local hyperthermia methods include intraluminal or endocavitary methods and inter-
stitial methods that may solve the focalization problem, and it may be expected also
that they could greatly enhance chemotherapy by decreasing the necessary dose and
diminish normal tissue damage (Petryk et al., 2009). The intraluminal treatment of
tumors situated nearby or within body cavities (e.g., rectum and esophagus) employs
probes, which are positioned inside the cavity and inserted into the tumor for the
direct heating of the tumor. The interstitial methods use probes or needles, which are
inserted, under anesthesia, into the tumor to treat tumors deep inside the body, as for
instance brain tumors. The tumor is thus heated to higher temperatures than the
external techniques can do. Accompanying imaging techniques, for instance, ultra-
sound may help properly guiding the probe within the tumor.
Depending on the desired temperature and power levels, procedural duration, it
may be distinguished between (1) diathermia—up to 41 C, used in physiotherapy

(rheumatism and related diseases); (2) hyperthermia, from 41 Cto45 C, used in oncol-

ogy to enhance the efficiency of other cancer treatments; (3) thermal ablation (TA),

above 45 C, used to destroy localized tumor formations. Table 8.1 summarizes the
thermal therapy methods that utilize EMF sources.

Hyperthermia in the range of 42 C 45 C for periods of 30 60 min causes
irreversible cellular deterioration through protein denaturation (Dutreix et al., 1978)as
shown in Habash et al. (2006), and the time to irreversible cellular harm decreases
exponentially when the tissue temperature rises to 50 C.