Periodic Reporting for period 2 - AMPHORA (ACOUSTIC MARKERS FOR ENHANCED REMOTE SENSING OF RADIATION DOSES)
Reporting period: 2018-11-01 to 2020-04-30
AMPHORA aims to develop a non-invasive in-situ dosimetry system for radiation therapy with the potential of on-line dose assessment by casting ultrasound contrast agents (UCAs) into dose sensing theranostic devices. UCAs will be upgraded to injectable dose-sensitive and targeted devices that gather in tumor tissue and translate imparted radiation dosage into a modulation of their acoustic response upon ultrasound interrogation. Tailored ultrasound imaging and advanced signal processing algorithms will be developed to extract the (change in) acoustic signature of UCAs from backscatter data and to translate this information into a 2D or 3D dose distribution map. The specific objectives of this project are the design, development and pre-clinical validation of the aforementioned UCA based dosimetry system and a customised ultrasound read-out technology.
Upon successful completion, AMPHORA will have enabled the assessment of the effective radiation dose distribution in (and around) the tumor, offering an advanced and objective means to compare and evaluate treatment efficacy of different radiotherapy modalities. Such novel technology would revolutionize quality assurance and treatment follow up in radiotherapy, which also unmistakably will lead to increased patient safety and improved treatment protocols. Moreover, AMPHORA is expected to trigger an avalanche of novel technologies for radiation therapy delivery and to pave the way for other in-vivo UCA based distributed sensing applications.
The ultrasound read-out technology is based on the quantitative assessment of local acoustic properties of the (ultrasound) medium. Hereto, a prior-art algorithm to estimate local acoustic attenuation was further developed in order to make it more performing. Experimental data shows that the proposed solution is indeed faster as well as more accurate and precise than the original approach and allows estimating ultrasound wave attenuation in real-time. This combined with the fact that pre-AMPHORA pilot data showed lipidic UCA’s to change their attenuation characteristics upon irradiation is very promising towards reaching the final goal of AMPHORA. Importantly, the read-out technology developed remains generic in that it can be generalized to simultaneously estimate backscatter and non-linear characteristics of the propagating medium. This is the topic of going work and might be important in case the newly developed UCA’s behave different in their acoustic response to radiation than the pre-AMPHORA commercial agent tested. Finally, in order to translate this read-out technology to a clinical setting, a customized ultrasound system is required. During the first reporting period, systems specifications have been defined based on interaction with the Clinical Advisory Board (CAB) of AMPHORA. As such, the design and development of a 1024-channel ultrasound platform to be equipped with a 32x32 custom-made matrix array transducer has started. For the latter, simulation studies have been carried out (and are still on-going) as for optimal transducer design before its effective (expensive) fabrication starts. Overall, development of the ultrasound read-out technology is thus moving forward according to plan.
Pursuing potential means to assess the radiation dose distribution in (and around) the tumor, this project intends to grant radiation therapists and physicists access to the currently unmeasurable very essence of their treatment. Successful completion of this project would therefore revolutionize quality assurance and treatment follow up, unmistakably leading to increased patient safety and offering advanced and objective means to compare and evaluate treatment efficacy of different radiotherapy modalities. This could potentially even further improve treatment protocols. Moreover, emergence of in-situ dose information is expected to trigger an avalanche of technological advances exploiting this new source of information to herald a new era in adaptive radiotherapy further focusing on treatment delivery specificity and tumor conformity. In addition, as ultrasound contrast agents provide a highly flexible platform, successful completion of this project is expected to pave the way for other in-vivo UCA
based distributed sensing applications (e.g. temperature, acidity, etc.). As such, the potential impact of AMPHORA ranges well beyond the field of radiotherapy.