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Sub-Millimetre Precision for Range Verification in Cancer Radiation Therapy

Fri., Sep. 13, 2019 3:30 p.m. - Fri., Sep. 13, 2019 4:30 p.m.

Location: CL 112

Abstract: Radiation therapy with hadrons (protons or C-12 ions) holds great promise for several cancer sites including breast cancer due to its steep dose gradient at the end of its range, the so-called Bragg peak, which, if properly employed and taken full advantage of, can spare healthy surrounding tissue from radiation exposure. Hadron therapy also is an option for tumours which do not respond to gamma-ray therapy and chemotherapy.

One of the great hindrances of hadron therapy (HT) is the limitation to locate the position of the Bragg peak in the tumor in real time in the patient during treatment. To this end, several efforts are ongoing to improve HT, including in-vivo verification of the hadron beam range. The goal is to inform clinical staff in real time of deviations between the treatment plan and delivered treatment to instantly correct or at least to compensate in a future fraction.

After introducing the basics of HT, I present two new approaches for range verification in HT, based on monitoring nuclear reactions using state-of-the-art nuclear physics equipment. The first method is based on gamma-ray spectroscopy of characteristic gamma rays, emitted from a tumour marker. The first successful experiments at TRIUMFs proton treatment facility indicate that sub-mm range verification is possible using this technique. The second method uses tracking of secondary charged particles, emitted during treatment, to achieve precise online monitoring in carbon ion therapy.