Grant: Operating Grant

Nearly half of the cancer patients will receive radiation therapy for their treatment. Image guided radiotherapy promises to precisely align the diseased volume with the radiation beams in real time, and it requires three dimensional imaging of the patient in treatment position regularly during the course of radiation therapy. The precise alignment of the patient with the radiation beams, in real time, will greatly eliminate the amount of healthy tissue which is unnecessarily irradiated in order to ensure accurate radiation dose delivery to the tumor that could move day to day due to patient setup and during the treatment due to involuntary motion. The ideal imaging system would specifically depict the tumor in addition to the normal patient anatomy even during the activation of the treatment beam using no extra radiation dose to the patient. A magnetic resonance imaging system integrated with a radiation therapy treatment linac holds a great promise to satisfy all these requirements. At Cross Cancer Institute, we are developing an integrated magnetic resonance imaging linac system. In such a system, the radiofrequency coils that are used to form magnetic resonance image will be irradiated. The present proposal aims to investigate various effects of short, intense radiation pulses of linac on the operation of radiofrequency coils. In particular, we will investigate the transient signal generated in radiofrequency coils due to radiation as a function of instantaneous dose rate, coil configuration, type of holding material for the coil. We will also investigate the degradation in the coil performance related to magnetic resonacne imaging as a function of accumulated radiation dose. In addition, the effect of placing the coil around or on the patient's skin on the radiation dose received by patient's skin will be investigated. The successful completion of this project will allow us to optimize the coil design for MRI linac project.