Grant: Operating Grant

Radiation therapy, the cancer therapy that makes use of ionizing radiation, can be performed with different types of radiation. The majority of therapy is done with photons, which have the property that they deposit dose in healthy tissues beyond the tumour, i.e., tissues that we would like to avoid giving radiation. Electron radiation is used currently at a much smaller scale although it could be very useful since the electron penetration depth can be accurately controlled and hence used to avoid dose delivery to healthy tissues. In this project we develop techniques to upgrade electron therapy technology. In the previous research we have invented, designed and built a new type of "(few-leaf) collimator" (or "FLEC"), i.e., a device that focuses the electron radiation for radiation therapy and that can be used on current commercial radiation equipment for cancer treatment. The collimator blades move during the treatment and the energy of the electrons is made to change during the treatment. These actions are termed "modulation" hence the term "modulated electron therapy". By doing so we can conform the high electron radiation dose tightly around the tumor and much better avoid normal healthy tissues. We have established that modulated electron radiation can help in a great way to reduce dose to healthy organs but that its performance and range of application can be greatly enhanced if it is used in conjunction with traditional photon radiation (hence, mixed-beam therapy). We use Monte Carlo simulation techniques with which we can follow the individual radiation particles and their path as they emerge from the radiation equipment through the collimator into the patient and we calculate how they deposit energy in the patient. Mixed beam therapy is very complex to plan and deliver so we develop novel techniques to verify mixed-beam therapy using sophisticated dose measurement techniques.