DEVELOPMENT AND EVALUATION OF A NOVEL TECHNOLOGY FOR MONITORING PATIENT MOTION DURING STEREOTACTIC RADIOTHERAPY

Abstract

Stereotactic Radiosurgery (SRS) and stereotactic Body Radiotherapy (SBRT) are two of the most precise therapeutic radiation delivery techniques available. These techniques involve accurate delivery of high radiation doses to the target volume while minimizing the amount of radiation received by the adjacent healthy tissue. To achieve this precision, patients need to be accurately positioned with respect to the treatment unit, and the position must be maintained throughout the treatment delivery. While immobilization techniques reduce patient motion, they do not eliminate it. Thus, there exists a need for continuous position monitoring during treatment. An ideal monitoring system would provide real-time, high-accuracy measurements of patient position without using ionizing radiation or reliance on deformable surrogates such as skin. Additionally, the ideal system would be insensitive to the thermoplastic immobilization material and would not require direct view of the patient. While multiple monitoring systems are used in practice currently, none meet all of these requirements. Our research is focused on the development of a novel and non-invasive capacitive monitoring method that can fulfill the above-mentioned prerequisites. This thesis includes four manuscripts. The first, entitled “A novel intra-fraction motion monitoring system for stereotactic radiosurgery: proof of concept,” describes the design and implementation of a prototype capacitive monitoring device capable of performing 3D motion detection. The second manuscript, “Finite Element Analysis of a capacitive array for 6D intrafraction motion detection during stereotactic radiosurgery,” focuses on the use of finite element analysis to simulate different array designs and introduces a method to compare the sensitivity of different designs to determine a capacitive array design capable of 6D cranial motion detection. The third manuscript, “Six-dimensional intrafraction cranial motion detection using a novel capacitive monitoring technique: evaluation with human subjects,” presents the results of a volunteer study with the most promising capacitive array for 6D cranial motion detection. The fourth manuscript, “Capacitive monitoring system for real‐time respiratory motion monitoring during radiation therapy,” describes the implementation of capacitive monitoring technique for respiratory motion detection during SBRT. These manuscripts form the basis for design, fabrication, and performance evaluation of capacitive monitoring systems for cranial and respiratory-induced intrafraction motion.