Superficial hyperthermia (HT) is a therapeutic technique used in conjunction with chemo- and/or radio-therapy to treat superficial tumours, i.e. lesions within a few cm from the skin layer. HT goal is to induce into the tumour a temperature of about 40°C ¿ 45°C for about 60 min. In microwave HT, the temperature increase is achieved through the absorption into the tissue of an electromagnetic (EM) field at microwave (MW) frequencies, radiated by an antenna placed on the surface of the human body. Clinical trials proved that treatment outcomes are critically related to the quality and timing of the HT sessions, i.e. the ability of reaching and maintaining HT temperatures at the target, while ¿ at the same time ¿ sparing the healthy tissue. Maintaining the antenna positioning and HT temperatures all along a single treatment duration, as well as accurately reproducing antenna placement in all the treatments prescribed by the therapeutic program, remain critical issues not addressed in current systems. At present, the antenna is manually located by the clinician and a passive arm keeps it in a fixed pose, without any automatic spatial control or imaging guidance. This leaves the accuracy and reproducibility, and hence efficacy, of the therapy difficult to guarantee and monitor. Aim of the research is to investigate the use of a robotic arm to accurately move the antenna to the planned position and keep it at the desired pose for the whole treatment duration, despite possible patient¿s movements. In the project, an antenna in clinical use will be characterized to calculate the EM power transferred to the tissue and the EM compatibility with a robotic arm used for healthcare applications. Human-robot physical interaction control methodologies, combined with localization and tracking algorithms, will allow achieving safe and easy positioning and adaptation of the antenna in a human-robot cooperative fashion, thus improving treatment accuracy and reproducibility.
According the World Health Organization (WHO), cancer is the second leading cause of death globally, accounting for an estimated 9.6 million deaths in 2018 (https://www.who.int/news-room/fact-sheets/detail/cancer; last accessed on June 1st, 2020). The number of new cancer cases is globally on the rise. According WHO projections, between 2008 and 2030, the number of new cancer cases is expected to increase more than 80% in low-income countries, and about 40% in high-income countries. According the above, it is projected that by 2030 between 10 and 11 million cancers will be diagnosed each year in low- and middle-income countries (https://www.who.int/cancer/resources/keyfacts/en/; last accessed on June 1st, 2020). Many cancers have a high chance of cure if detected early and treated adequately (https://www.who.int/cancer/resources/keyfacts/en/; last accessed on June 1st, 2020). Accordingly, there is increasing research both in the prevention and screening of cancer types, as well as in new methodologies for treatment.
Hyperthermia (HT) is gaining increased attention by clinicians due to its proven synergistic effect with radio and chemo-therapy, with particular reference to aggressive tumours as recurrent breast tumours, cervical, rectum, and bladder cancer. However, at present HT suffers from a poor reproducibility of the achieved results in the clinical practice, which is believed to be due to poor treatment planning procedures, lack of availability of real time temperature distribution images, incapability of real-time adjusting the HT device following feed-back information from temperature sensors, too time-consuming duration of the procedure. With reference to the time duration of an HT treatment, this is made by a first step in which an electromagnetic (EM) model of the patient is derived from diagnostic CT images, then treatment planning simulations are run to define optimum location of the antenna with respect the target tumour. Successively, at the appropriate timing with respect the concurrent radio and/or chemotherapy, the patient is prepared, with proper positioning of temperature sensors, and the antenna is manually located in the planned position. Finally, the treatment starts with a heating up period which can last up to 30 min; when the temperature reaches the defined values, the actual time of treatment starts, lasting about 60 min.
At present, HT is performed in few centres all around the world; most of them perform HT treatments since the final decades of the past century so that involved people have a deep knowledge of HT mechanisms and profound confidence in its potentialities. However, the above listed deficiencies prevent the widespread adoption of HT all around the world.
The idea at the basis of the present proposal is to integrate the use of a robotic arm with a superficial HT device. Several improvements in the HT treatment are envisaged following the proposed approach. At first, the robotic arm allows accurately locating the microwave (MW) antenna, thus improving treatment reproducibility and at the same time speeding-up the treatment procedure with particular reference to the pre-treatment phases. Moreover, reproducibility of positioning applies not only with reference to the treatment planning definitions, but to successive HT sessions along the weeks of the HT treatment. During the treatment, the robotic arm allows fine tuning of the antenna location both following micro- and macro- patient¿s movements and following feed-back signals from temperature sensors. This will improve treatments efficacy, by optimizing the temperature distribution all along the treatment duration. Finally, the use of a robot will simplify and improve the treatment of tumours whose size is larger than the area covered by one antenna but too small to allow the use of two antennas. In this scenario, it is possible to exploit the slower thermic dynamics with respect to the electromagnetic one, to cover the tumour region by moving the antenna among multiple positions.
Minimizing human errors and reducing the time needed to set and execute the treatment, the proposed system will allow greater precision and workflow speed, to which follow higher thermal doses and thus better clinical outcomes. In turn, this will result in a cost reduction for the healthcare system both in terms of personnel cost, thanks to the simplification and speeding of the procedure, and in terms of the impact of the positive clinical outcome reducing tumours recurrence rate and improving survival.
Besides improvements in the HT treatments, the project will allow the proponents to increase their knowledge on the electromagnetic behaviour of superficial HT devices, thus allowing developing new solutions with better radiation performances, and of the use of robotic arms in healthcare applications, thus strengthening their skills in dynamic simulation and control of robotic systems.