Conformal radiotherapy cancer treatment with multileaf collimators: improving performance with real-time feedback

For over a century, physicians have used external X-ray radiation as a treatment option to destroy or impede the growth of cancerous tumours. This treatment delivers a dose of radiation to a tumour with the goal of irradiating cancerous tissue, while sparing surrounding healthy tissue. To accommodate tumour movement during the treatment and errors in aligning the tumour with the radiation beam, the area to be irradiated is typically made larger than the area of the tumour; this practice ensures the cancerous tissue is irradiated, but is detrimental to the surrounding healthy tissue. Recent medical imaging advances have motivated research studying the use of feedback in radiotherapy to track the tumour position in real time. Feedback permits a reduction in the radiation beam size during treatment, possibly reducing damage to healthy tissue adjacent to the tumour. This paper extends previous results and proposes a feedback control system for the latest generation of radiotherapy machines