title: Magnetic resonance-based thermometry during laser ablation on ex-vivo swine pancreas and liver.
abstract: Laser Ablation (LA) is a minimally-invasive procedure for tumor treatment. LA outcomes depend on the heat distribution inside tissues and require accurate temperature measurement during the procedure. Magnetic resonance imaging (MRI) allows a non-invasive and three-dimensional thermometry of the organ undergoing LA. In this study, the temperature distribution within two swine pancreases and three swine livers undergoing LA (Nd:YAG, power: 2 W, treatment time: 4 min) was monitored by a 1.5-T MR scanner, utilizing two T1-weighted sequences (IRTF and SRTF). The signal intensity in four regions of interest, placed at different distances from the laser applicator, was related to temperature variations monitored in the same regions by twelve fiber Bragg grating sensors. The relationship between the signal intensity and temperature increase was calculated to obtain the calibration curve and to evaluate accuracy, sensibility and precision of each sequence. This is the first study of MR-based thermometry during LA on pancreas. More specifically, the IRTF sequence provides the highest temperature sensitivity in both liver (1.8 ± 0.2 °C(-1)) and pancreas (1.8 ± 0.5 °C(-1)) and the lowest precision and accuracy. SRTF sequence on pancreas presents the highest accuracy and precision (MODSFRT = -0.1 °C and LOASFRT = [-2.3; 2.1] °C).
authors.affiliation: Unit of Measurements and Biomedical Instrumentation, Center for Integrated Research, Università Campus Bio-Medico di Roma, Via Álvaro del Portillo, 21, 00128 Rome Italy.
authors.forename: G
authors.initials: G
authors.lastname: Allegretti
authors.affiliation: Unit of Measurements and Biomedical Instrumentation, Center for Integrated Research, Università Campus Bio-Medico di Roma, Via Álvaro del Portillo, 21, 00128 Rome Italy. Electronic address: p.saccomandi@unicampus.it.
authors.forename: P
authors.initials: P
authors.lastname: Saccomandi
authors.affiliation: Unit of Radiology, Center for Integrated Research, Università Campus Bio-Medico di Roma, Via Álvaro del Portillo, 200, 00128, Rome, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Giurazza
authors.affiliation: Laboratory of Photonics and Fiber Optic Sensors, ENEA - CR Frascati, via Enrico Fermi 45, 00044, Frascati, Rome, Italy.
authors.forename: M A
authors.initials: MA
authors.lastname: Caponero
authors.affiliation: Unit of Radiology, Center for Integrated Research, Università Campus Bio-Medico di Roma, Via Álvaro del Portillo, 200, 00128, Rome, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Frauenfelder
authors.affiliation: Unit of Gastrointestinal Endoscopy, Center for Integrated Research, Università Campus Bio-Medico di Roma, Via Álvaro del Portillo, 200, 00128, Rome, Italy.
authors.forename: F M
authors.initials: FM
authors.lastname: Di Matteo
authors.affiliation: Unit of Radiology, Center for Integrated Research, Università Campus Bio-Medico di Roma, Via Álvaro del Portillo, 200, 00128, Rome, Italy.
authors.forename: B
authors.initials: B
authors.lastname: Beomonte Zobel
authors.affiliation: Unit of Measurements and Biomedical Instrumentation, Center for Integrated Research, Università Campus Bio-Medico di Roma, Via Álvaro del Portillo, 21, 00128 Rome Italy.
authors.forename: S
authors.initials: S
authors.lastname: Silvestri
authors.affiliation: Unit of Measurements and Biomedical Instrumentation, Center for Integrated Research, Università Campus Bio-Medico di Roma, Via Álvaro del Portillo, 21, 00128 Rome Italy.
authors.forename: E
authors.initials: E
authors.lastname: Schena
mesh_terms: D000818:Animals; D002138:Calibration; D053685:Laser Therapy / Q000295:instrumentation / Q000379:methods*; D007834:Lasers; D016014:Linear Models; D008099:Liver / Q000033:anatomy & histology / Q000502:physiology / Q000601:surgery*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods; D053783:Magnetic Resonance Imaging, Interventional / Q000295:instrumentation / Q000379:methods*; D010179:Pancreas / Q000033:anatomy & histology / Q000502:physiology / Q000601:surgery*; D013552:Swine; D013696:Temperature; D062125:Thermometry / Q000295:instrumentation / Q000379:methods*
keywords: Fiber Bragg grating sensors; Laser ablation; Liver; MR-based thermometry; Pancreas