Audiovisual biofeedback

Radiotherapy is an effective and widely utilised method of cancer treatment. In Australia alone, 115,000 cancer patients are newly diagnosed each year, 40% of which receive radiotherapy as part of their treatment plan. More than 50% of lung cancer patients are treated with radiotherapy; however, the precision of radiotherapy can be reduced due to respiratory-related tumour motion, leading to the irradiation of healthy surrounding tissues in addition to the tumour itself, resulting in a significant increase in radiation-related toxicity. A key problem is inadequate respiratory-related direct tumour motion management.

An audiovisual (AV) biofeedback system has been developed at the University of Sydney which audio-visually guides a patient to produce a regular breathing pattern which is beneficial to both medical imaging and radiation oncology applications. This system can reduce average cycle-to-cycle variations in respiratory displacement and period, leading to improved image quality and tumour control. Therefore, clinical teams can (1) enable clearer delineation of the tumour for cancer imaging, and (2) improve radiation beam targeting of tumours affected by respiratory motion during treatment delivery.

The AV biofeedback system can operate in conjunction with real-time imaging such as MRI, CT, PET and ultrasound for direct tumour motion management. The AV biofeedback system can provide clinical teams and their patients’ optimal tumour motion management, resulting in a decrease in healthy tissue toxicity and an increase in patient survival rate and quality of life through image-guided radiotherapy (IGRT). This technique can also be applicable to a diverse range of regions affected by respiratory motion, such as the lungs, pancreas, liver, kidneys and oesophagus.