[Triumf-seminars] TRIUMF Colloquium today at 14:00

[TRIUMF Seminars]

Date/Time: Thu 2022-02-24 at 14:00

Location:  Remote              

Speaker:   Dennis Muecher (U of Guelph)

Title:     Range Verification in Hadrontherapy: Limiting Side Effects in State-of-the-Art Radiation Therapy

Abstract: Approximately 50% of all cancer patients undergo radiation therapy as a part of their treatment, often in combination with surgery and chemotherapy. Lately, Hadron-Therapy (HT), especially with protons and carbon ions, has gained popularity as a method of radiation therapy, with currently 86 hadron therapy centers in operation and 71 being planned and built worldwide. 
HT is a powerful treatment technique as it delivers radiation finely tailored to a tumor, sparing surrounding healthy tissue. This is achieved with a characteristic dose profile in tissue, with very steep dose gradients at the end of a finite range (the so-called Bragg peak), which is not present in other radiation-therapy modalities. This allows to escalate the dose in the tumor. On the flip side, one of the current key challenges in HT is range verification: determining the stopping point of the beam in vivo. Movement of the patient, changes in patient morphology between treatments, and other uncertainties in treatment setup or beam delivery may result in the Bragg peak over-or under-ranging the tumor during treatment. Improper ranging would result in substantial radiation dose being delivered to healthy tissue, causing unnecessary damage, and reducing the effective dose to the tumor, weakening the prescribed treatment.
In a collaboration of the University of Guelph and TRIUMF, we have developed a new approach to measure the range of the treatment beam in-vivo in real-time during treatment. The method makes use of characteristic gamma rays, emitted from a fiducial marker, seconds after each beam pulse. I will report on the first successful experiments at TRIUMF's Proton Irradiation Facility. We have recently expanded our technique to heavier beams, and I will show results from the first experiment with O-16 beam at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University. In that same experiment, we also were able to monitor relative range shifts with sub-millimeter precision using "Interacting Vertex Imaging" with silicon detectors. This complementary approach to range verification has the potential to monitor the beam range in vivo for each setting in state-of-the-art active scanning irradiation.

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Meeting URL:
https://uvic.zoom.us/j/83646797624?pwd=ckR6blBmaDZGY0dSYmd0bldlOXoxUT09

Meeting ID: 836 4679 7624
Password: 887005



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