Microwaves are included between 3OO Mhz and 300 Ghz in the spectnum of  electromagnetic waves, with relative wave length ranging (in vacuo) between 100 m and 1 mm. When they dìrectely  react  with adsorbant dielectric materials (e.g. biological tissues) they induce heating. This is produced by the direct action of microwaves on free charges (ions) and polar  molecules (dipols) inside the treated dialectric medium, without the passage of condution currents, but only by the action of movement and orientation produced on the electrìc charges by the electromagnetic energy. The water content of the tissues is very important for the variation of their dielectric constant and the following capacity to be heated. 
The higher the frequency, the more intense and  focalized is the thermic effect, while the capacity of penetration is lower, involving small volumes of tissue. 
The modulation of the microwave coagulation is possible by variations of  frequencies and power, permitting the best results on the tissues to be treated. 

When microwaves are administrated inside the tissues by special needle-like antennas at different power and wave lenths, they can produce a very intense heating (over 100° C) with a complete and homogeneous coagulation, obtaining a definitive hypertermic effect just in the place where ìt is useful. 

OUR EXPERIENCE 
Since 1993, Dr.Luca E. Vannucci, has been working on the experimental application of microwave acutely induced hyperthermia to obtain in situ extended thermic ablation of  the neoplastic tissue using the high coagulative potential of the microwaves. 

After preliminary  studies on egg albumin, to demonstrate the homogeneity and local extenntion of the coagulative processes, and on autoptic animal organs (pig and cow liver and kidney), to control the previous results in read parenchimas (Fig. 1) 
 

 

we treated pig and rat liver in vivo, to demonstrate the possibility of a safe ìntraparenchìmal approach,to verify the extention and the homogeneity of the coagulation in living organs with active blood circulation, the compliance to the treatment by the animai, and the riparative process following the coagulative necrosis, in view of clinical applications in man. 

The Research is particularly devoted to the treatment of large neoplasms that are outside the usual hyperthermic localized treatments with radiofrequencies and laser because exceding the limiting volume for these tecniques, and expecially for those cancers that are largely vasculated and easily bleeding. 

The result of the treatment is the homogeneus coagulative necrosis quickly showing parvìcellular perilesional infiltration and pericoagulative fibrosis.The discarding of the necrotized tissue resulted progressive and without local complications (e.g.:colliquation and infections). 
 

ETHICAL APPROVAL 
The Ethical Commettee of the University of Pisa approved the project of treatment of locally advanced, easily bleeding and normally untreatable neoplasms. 
 

CLINICAL CASES EXPERIMENTALLY TREATED 
At present, 3 cases of large cancer recurrences (1 chondrosarcoma, 2 spinocellular carcinomas) were treated obtaining a very satisfying debulking and complete bleeding control,with very good palliation for the patients. 
(Fig. 2-3-4) 
 
                      Fig.2                                                   Fig.3                                                Fig.4

COLLABORATIONS 
This Research is performed with the technical collaboration of the Institute of Atomic and Molecular Physics of the CNR (National Research Commettee) at  Pisa with which we aredeveloping new kind of probes and collecting more scientific information for better antineoplastic and surgical use. 
 

FACILITIES AND INSTRUMENTS 
The experimental study on animai specimens and anìmals was performed in our LABORATORY OF EXPERIMENTAL SURGICAL ONCOLOGY (see). 
The minipig liver treatment was performed in S.Piero a Grado Surgical Facility for large animals (see). 
 

ONGOING RESEARCHES 

• Evaluation of biological modifications of the organs after acute hyperthermic treatment. 
• Protection of delicate structures in complex anatomical situations. 
• New clinical applications. 
• New dedicated tools.