Allegretti G, Saccomandi P, Giurazza F, Caponero M A, Frauenfelder G, Di Matteo F M, Beomonte Zobel B, Silvestri S, Schena E
Unit of Measurements and Biomedical Instrumentation, Center for Integrated Research, Università Campus Bio-Medico di Roma, Via Álvaro del Portillo, 21, 00128 Rome Italy.
Unit of Measurements and Biomedical Instrumentation, Center for Integrated Research, Università Campus Bio-Medico di Roma, Via Álvaro del Portillo, 21, 00128 Rome Italy.
Med Eng Phys. 2015 Jul;37(7):631-41. doi: 10.1016/j.medengphy.2015.04.001. Epub 2015 Jun 5.
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).
激光消融（LA）是一种用于肿瘤治疗的微创手术。LA的治疗效果取决于组织内部的热分布，并且在手术过程中需要精确测量温度。磁共振成像（MRI）能够对接受LA的器官进行非侵入性三维温度测量。在本研究中，使用1.5-T MR扫描仪，利用两个T1加权序列（IRTF和SRTF），监测了两只猪的胰腺和三只猪的肝脏在接受LA（Nd:YAG，功率：2 W，治疗时间：4分钟）时的温度分布。在距激光照射器不同距离处设置的四个感兴趣区域中的信号强度，与十二个光纤布拉格光栅传感器在相同区域监测到的温度变化相关。计算信号强度与温度升高之间的关系，以获得校准曲线，并评估每个序列的准确性、灵敏度和精密度。这是首次在胰腺LA过程中基于MR进行温度测量的研究。更具体地说，IRTF序列在肝脏（1.8±0.2°C⁻¹）和胰腺（1.8±0.5°C⁻¹）中均具有最高的温度敏感性，但精度和准确性最低。胰腺上的SRTF序列具有最高的准确性和精密度（MODSFRT = -0.1°C，LOASFRT = [-2.3; 2.1]°C）。
