title: Electrical properties of prostatic tissues: II. Spectral admittivity properties.
abstract: OBJECTIVE
  The electrical properties of prostate tissues gauged at discrete frequencies provide sufficient contrast to discriminate malignant from benign prostatic tissues. The frequency dependence of these properties is also a function of tissue morphology. We evaluated the potential of this spectral dependence to provide additional diagnostic information for prostate cancer detection.
  
  
  METHODS
  Electrical conductivity and permittivity were recorded from 50 ex vivo prostates at 31 logarithmically spaced frequencies of 100 Hz to 100 kHz. We used a well established, 4 parameter (sigma(infinity), Delta sigma, f(c) and alpha) model to describe individual spectra with each model parameter influenced by tissue morphology. We evaluated these parameters in terms of discriminatory power using ROC curves.
  
  
  RESULTS
  Of the 4 spectral parameters sigma(infinity) and f(c) were significantly greater in cancer than in benign tissues and Delta sigma was significantly more negative in cancer than in benign tissues (each p <0.0001). f(c) provided the maximum discriminating power with an ROC AUC of 0.821 and 81.5% specificity at 70% sensitivity. Also, sigma(infinity) and Delta sigma provided high levels of discrimination with an AUC of 0.770 and 0.782, respectively.
  
  
  CONCLUSIONS
  Spectral electrical admittivity properties provide sufficient levels of ex vivo cancer discrimination that may potentially enhance disease localization when prostate cancer is suspected. The development of novel technologies gauging these properties in vivo has the potential to provide new tissue characterizing tools for prostate cancer detection and identification.
authors.affiliation: Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755, USA. ryan.halter@dartmouth.edu
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Halter
authors.forename: Alan
authors.initials: A
authors.lastname: Schned
authors.forename: John
authors.initials: J
authors.lastname: Heaney
authors.forename: Alex
authors.initials: A
authors.lastname: Hartov
authors.forename: Keith D
authors.initials: KD
authors.lastname: Paulsen
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis / Q000503:physiopathology*; D003937:Diagnosis, Differential; D017097:Electric Impedance; D055724:Electrophysiological Phenomena; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D011467:Prostate / Q000502:physiology*; D011470:Prostatic Hyperplasia / Q000175:diagnosis / Q000503:physiopathology*; D011471:Prostatic Neoplasms / Q000175:diagnosis / Q000503:physiopathology*
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