Three dimensional ultrasonic monitoring of interstitial thermal tumor therapies: in vivo results

One of the most important problems of interstitial thermal therapies of liver metastases is the non-invasive localization and measurement of the coagulated volume. In this study we propose to use three dimensional (3-D) information to evaluate the precision of ultrasound monitoring of thermal tumour therapies under in vivo conditions. For evaluation 3D reconstructions of optical thin slice data of the coagulation volume are compared to 3D-reconstructions of attenuation change ultrasound datasets. The derivation of differential attenuation volumes is performed. The co registration of both volumes is possible. Motion artefacts can be overcome. The results of 3 dimensional ultrasound monitoring of Nd:YAG laser induced (LITT) and radio frequency induced (RFITT) coagulation within in vivo pig liver specimen are presented. The comparison of ultrasonically and optically measured 3D-coagulation volumes show good geometric agreement.