טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
Ph.D Thesis
Ph.D StudentWeiss Noam
SubjectNon-Invasive Monitoring of Thermal Ablation Procedures
Using X-Ray CT
DepartmentDepartment of Biomedical Engineering
Supervisors Professor Haim Azhari
Professor Nahun Goldberg


Abstract

In recent years minimally invasive thermal ablation treatments are growing ever more frequently into an accepted alternative for cancer treatment. This is especially true for tumors in the liver, kidneys, lung, and even bones. Such minimally invasive procedures include the placement of applicators that can apply radiofrequency (RF), microwave (MW), laser, irreversible electroporation (IRE), and high intensity focused ultrasound (HIFU).


The monitoring of such treatments remains a main predicament for a successful treatment.

The determination of heating rate, duration, and termination of the procedure, is crucial to ensure that the entire tumor was destroyed. Furthermore, it is also needed to ensure that ablative margins around the tumor are induced while avoiding over-treating of adjacent potentially sensitive structures.


This work focused on the use of repeated X-ray CT imaging during thermal ablation to produce real-time feedback to the physician regarding the extent of the ablation zone. We have developed several methods which utilize image analysis for noninvasively estimating the ablated zone, as well as the tissue temperature, and safety zone margins. These methods are based on analysis of changes in the CT Hounsfield Units values, during the ablation procedure.


Our noninvasively obtained ablation zone size estimations have yielded results which are very close to the true ablation size values, measured on gross pathology ex-vivo liver specimens post ablation. Hence, it is concluded that the developed methods could potentially lead to the establishment of a new clinical tool that will permit real time monitoring of the development of the ablation zone.