Computed tomography monitoring of the ice ball during cryoablation of metastatic bone tumors

Percutaneous imaging-guided cryoablation (PICA) is one of the methods of oligometastatic bone lesions local treatment. The success of the percutaneous cryoablation depends on the achievement target temperature in the tumor, which determines the relevance of effective intraoperative monitoring of the boundaries of the ice ball.This work aimed to find ways to improve the definition of the boundaries of the ice ball during cryoablation of bone metastases under CT guidance . 106 PICA were performed in 84 patients aged 35 to 74 years with bone metastases at the N.N. Petrov NMRC of Oncology. The size of bone metastases was from 7 to 101 mm (40.3±17.7 mm). Indications for surgery were oligometastatic bone lesion and/or pain of 4 or more points on a visual analogue scale . To improve the visualization of the fuzzy boundaries of the ice ball, methods for determining the boundaries of the ice ball have been proposed. In 56 cases (53%), when the intraosseous part of the ice ball wasn’t visible, the boundaries of the ice ball were designed taking into account changes in soft tissues at the level of metastases by finishing the corresponding invisible part of the ice ball.In 24 cases (23%), due to artifacts from cryoprobes during an axial plane, the method of tilt of CT gantry was used, which allowed to improve the quality of visualization.The proposed methods make it possible to increase the effectiveness of intraoperative monitoring of the PICA in bone metastases, which can contribute to improving treatment results.