title: Use of permanent interstitial temperature self-regulating rods for ablation of prostate cancer.
abstract: OBJECTIVE
  We have examined a new technique for the thermal treatment of prostate cancer involving the percutaneous placement of small magnetic alloy rods into the gland in a procedure analogous to the placement of permanent brachytherapy seeds. When the patient and the implanted rods are placed in an extracorporeal alternating magnetic field, the rods heat and can produce tissue necrosis. The rods are temperature self-regulating and produce temperatures no higher than their preprogrammed regulation value. The rods are biocompatable permanent implants, comprised of cobalt and palladium.
  
  
  METHODS
  We examined rods that heat to 55 degrees, 60 degrees, and 70 degrees C. Patients are treated for 1-hour sessions and easily have multiple sessions.
  
  
  RESULTS
  Isolated rods produced little or asymmetrical necrosis. However, arrays of 70 degrees C rods placed within 1 cm of each other caused consistent necrosis between the rods. The temperature at the edge of the array dropped off quickly, and therefore, the rods can be placed within 2 mm of the capsule even posteriorly near the rectum.
  
  
  CONCLUSIONS
  Arrays of high-temperature rods can be employed for tissue ablation, while lower-temperature arrays could be used to produce hyperthermia in order to achieve synergism with adjuvant radiation therapy. The technique is applicable in an outpatient setting.
authors.affiliation: Department of Pathology, University of Iowa, Iowa City, USA. rdtucker@ibm.net
authors.forename: R D
authors.initials: RD
authors.lastname: Tucker
authors.forename: C
authors.initials: C
authors.lastname: Huidobro
authors.forename: T
authors.initials: T
authors.lastname: Larson
authors.forename: C E
authors.initials: CE
authors.lastname: Platz
mesh_terms: D004574:Electromagnetic Fields; D006801:Humans; D006979:Hyperthermia, Induced / Q000295:instrumentation / Q000379:methods*; D008297:Male; D009336:Necrosis; D011471:Prostatic Neoplasms / Q000628:therapy*; D019736:Prostheses and Implants; D018714:Radiotherapy, Adjuvant; D013696:Temperature