title: Experimental assessment of CT-based thermometry during laser ablation of porcine pancreas.
abstract: Laser interstitial thermotherapy (LITT) is employed to destroy tumors in organs, and its outcome strongly depends on the temperature distribution inside the treated tissue. The recent introduction of computed tomography (CT) scan thermometry, based on the CT number dependence of the tissue with temperature, overcomes the invasiveness of other techniques used to monitor temperature during LITT. The averaged CT number (ROI = 0.02 cm(2)) of an ex vivo swine pancreas is monitored during LITT (Nd:YAG laser power of 3 W, treatment time: 120 s) at different distances from the applicator (from 4 to 30 mm). The averaged CT number shows a clear decrease during treatment: it is highest at 4 mm from the applicator (mean variation in the whole treatment of -0.256 HU s(-1)) and negligible at 30 mm, since the highest temperature increase is present close to the applicator (i.e., 45 °C at 4 mm and 25 °C at 6 mm). To obtain the relationship between CT numbers and pancreas temperature, the reference temperature was measured by 12 fiber Bragg grating sensors. The CT number decreases as a function of temperature, showing a nonlinear trend with a mean thermal sensitivity of -0.50 HU °C(-1). Results here reported are the first assessment of pancreatic CT number dependence on temperature, at the best of our knowledge. Findings can be useful to further investigate CT scan thermometry during LITT on the pancreas.
authors.affiliation: Unit of Measurements and Biomedical Instrumentation, Center for Integrated Research, Università Campus Bio-Medico di Roma, Via Álvaro del Portillo, 21, I-00128, Rome, Italy. e.schena@unicampus.it
authors.forename: E
authors.initials: E
authors.lastname: Schena
authors.forename: P
authors.initials: P
authors.lastname: Saccomandi
authors.forename: F
authors.initials: F
authors.lastname: Giurazza
authors.forename: M A
authors.initials: MA
authors.lastname: Caponero
authors.forename: L
authors.initials: L
authors.lastname: Mortato
authors.forename: F M
authors.initials: FM
authors.lastname: Di Matteo
authors.forename: F
authors.initials: F
authors.lastname: Panzera
authors.forename: R
authors.initials: R
authors.lastname: Del Vescovo
authors.forename: B
authors.initials: B
authors.lastname: Beomonte Zobel
authors.forename: S
authors.initials: S
authors.lastname: Silvestri
mesh_terms: D055011:Ablation Techniques; D000818:Animals; D002138:Calibration; D005240:Feasibility Studies; D007834:Lasers; D010179:Pancreas / Q000000981:diagnostic imaging* / Q000528:radiation effects*; D013552:Swine; D013696:Temperature; D062125:Thermometry / Q000379:methods*; D014057:Tomography, X-Ray Computed