Ultra wideband microwave hyperthermia for brain cancer treatment
Doctoral thesis, 2022
In this thesis, we explore whether the current SAR-based treatment planning methods can be meaningfully translated to the UWB setting and propose new solutions for deep UWB microwave hyperthermia. We analyze the most commonly used cost functions for treatment planning optimization and discuss their suitability for use with UWB systems. Then, we propose a novel SAR-based cost function (HCQ) for UWB optimization that exhibits a high correlation with the resulting tumor temperature. To solve for the HCQ, we describe a novel, time-reversal-based, iterative scheme for a rapid and efficient optimization of UWB treatment plans. Next, we investigate the design possibilities of UWB brain applicators and introduce a fast E-field approximation scheme to quickly explore a large number of array configurations. The method determines the best antenna arrangement around the head with respect to the multiple objectives and requirements of clinical hyperthermia. Together, the proposed solutions manage to achieve the level of tumor coverage and hot-spot suppression that is necessary for a successful treatment. Finally, we investigate the benefit of integrating hyperthermia delivered by an optimized UWB applicator into the radiation therapy plan for a pediatric medulloblastoma patient. The results suggest that UWB microwave hyperthermia for brain cancer treatment is feasible and motivate efforts for further development of UWB applicators and systems.
Chalmers, Electrical Engineering, Signal Processing and Biomedical Engineering
Massimiliano Zanoli, Erika Ek, Hana Dobsicek Trefna, Antenna arrangement in UWB helmet brain applicators for deep microwave hyperthermia
But we have prepared two deadly traps: the blood stream carries a poison with it, chemical agents with the ability to tamper with and kill the cancer cells. From the outside, incoming high energy gamma rays bomb the tumor's DNA causing breaks in the nucleotide chain. The tumor struggles to stem the damage, its internal repair mechanisms being inhibited by the exerted rise in temperature. Eventually, the fight reaches a tipping point and the tumor retreats.
This epic tale is regularly played out in patients afflicted by tumors in the pelvis, in the abdomen, in the breast, in the neck, and in the extremities, with remarkable results. The boost in survival rates speaks clearly: hyperthermia works. But a whole group of people has been left out by this advancement, namely brain cancer patients. The main reason behind this is the difficulty in implementing a controlled heat delivery inside the head with high enough accuracy for the treatment to be safe and effective.
In the present work, we devise new techniques for the non-invasive thermal treatment of tumors in the brain. We devote particular attention to young patients, where the incidence of such diseases is the highest, and where the long-lasting side effects of traditional therapies severely degrade the quality of life of survivors. Thanks to improvements in the control of the thermal dose delivery by means of innovative system designs and sophisticated steering tools, we show that it is possible to achieve therapeutic temperatures even in the nastiest of tumors. The wish is for microwave hyperthermia to become a regular modality in brain cancer treatment, and finally exploit the benefits of this technique in younger sufferers.
Focused Microwave Intracranial Heating: towards mitigation of late side effects of childhood brain cancer treatment
Swedish Research Council (VR) (2021-04935), 2022-01-01 -- 2025-12-31.
Medical Equipment Engineering
Areas of Advance
Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 5235
HC4, Hörsalsvägen 14
Opponent: Dr. Petra H. Kok, Amsterdam UMC, The Netherlands