title: Hyperthermia in the treatment of cholangiocarcinoma: development and testing of an endobiliary microwave device.
abstract: OBJECTIVE
  The aim of this study was to create, perfect and test a hyperthermia balloon catheter for local treatment of cholangiocarcinoma. The device should induce hyperthermia in tumor tissue by acting locally in the bile duct lumen in contact with the tumor-infiltrated duct wall. In addition, it should exert tissue compression to cause an appreciable reduction in tumor microvasculature flow, thus improving thermal performance.
  
  
  METHODS
  According to the design specifications, the working temperature range should allow the device to be used for hyperthermia therapy either in combination with radiation and/or chemotherapy (radio/chemo-sensitizing effect at 42-45 degrees C) or alone (induction of coagulation necrosis above 65 degrees C). The balloon serves as an anchoring system during treatment and as a functional element to induce tissue compression. In vitro mechanical evaluation of the pressure/volume relationship, with the balloon inside rigid walled conduits, was performed. The heating shape around the catheter tip was determined by egg-white heating tests (coagulation at about 65 degrees C). Moreover, heating tests were carried out with explanted pig liver parenchyma. The temperature profile over time at different depths from the catheter axis was traced.
  
  
  RESULTS
  Three prototypes were manufactured. Mechanical functional tests showed that a 14 Fr deflated diameter balloon was suitable for bile duct diameters up to 11 mm. Thermal egg-white tests produced 4 cm long, 3 cm in diameter ellipsoidal heating figures in 30 min. In the biological tissue tests a coagulated area of similar geometry and comparable volume was produced.
  
  
  CONCLUSIONS
  The results of tests confirm the device's usefulness and versatility.
authors.affiliation: Dipartimento di Bioingegneria, Politecnico di Milano, Piazza Leonardo da Vinci, 32, Milan, Italy. Mantero@biomed.polimi.it
authors.forename: Sara
authors.initials: S
authors.lastname: Mantero
authors.forename: Iginio
authors.initials: I
authors.lastname: Longo
authors.forename: Gianfranco Beniamino
authors.initials: GB
authors.lastname: Fiore
authors.forename: Aldo
authors.initials: A
authors.lastname: Severini
mesh_terms: D000818:Animals; D001650:Bile Duct Neoplasms / Q000628:therapy*; D001653:Bile Ducts, Intrahepatic; D002404:Catheterization / Q000295:instrumentation*; D018281:Cholangiocarcinoma / Q000628:therapy*; D004867:Equipment Design; D006801:Humans; D006979:Hyperthermia, Induced / Q000295:instrumentation*; D008872:Microwaves / Q000627:therapeutic use*