October 11 Oct 11
12:00 PM - 01:00 PM
Tuesday Tue


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Stanford University School of Medicine

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Stanford CA, 94305
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Medical Physics Seminar - Liyong Lin PhD

Integrated Biological Optimization – Intensity-Modulated Proton Therapy (IBO-IMPT) for FLASH applications: An open-source framework for physicists, biologists, and physicians

Location: Zoom
Zoom Details
Webinar URL: https://stanford.zoom.us/webinar/register/WN_j1zCOA3wTUaOW1k9ue6zHQ
Dial: US: +1 650 724 9799  or +1 833 302 1536 (Toll Free)
Webinar ID: 981 4830 1798
Passcode: 366874

12:00PM – 1:00PM Seminar & Discussion



Sponsored by the Radiation Oncology, Division of Medical Physics


Liyong Lin PhD, Associate Professor at Emory University School of Medicine

I am an Associate Professor in the Emory University School of Medicine and a lead proton physicist at the Emory Proton Therapy Center. I am a member of the Therapy Medical Physics Committee of American Board of Radiology (ABR) and a fellow of the American Association of Physicists in Medicine (AAPM). 

As an expert on Monte Carlo (MC) methods and proton radiotherapy, I previously chaired the NRG workgroup for the application of MC methods in clinical trials and currently chair the NRG workgroup for stereotactic body proton therapy/ I am the physics co-chair of a newly approved NCI Phase 3 clinical trial “Phase III Prospective Randomized Trial of Primary Lung Tumor Stereotactic Body Radiation Therapy Followed by Concurrent Mediastinal Chemoradiation for Locally-Advanced Nonsmall Cell Lung Cancer” NRG-LU 008. I also chair of the AAPM task group TG349 to validate MC methods in commercial treatment planning systems. I have 77 peer-reviewed journal papers with H-index of 25 (Scopus). I am also the author of 2 AAPM task group reports, 1 PTCOG lung committee consensus paper and 1 NRG MC Workgroup paper.


A bundled IBO-IMPT framework provides degenerate solutions to simultaneously optimize contributions from dose, dose rate, and LET. The framework creates both spot maps for proton pencil beam scanning radiotherapy and CAD files to create patient-specific ridge filter assembly. The ridge filter assembly passively modulate energy of a transmission beam to allow conformal dose delivery. The rationale for using IBO-IMPT is that dose, dose rate, and LET are inextricably linked. For example, a higher LET can increase RBE up to 1.3 fold, whereas FLASH dose rates can reduce RBE (for normal tissue) by up to 50%. Thus, dose rate and LET may negate each other’s contribution unless each term is explicitly optimized. In addition, dose thresholds for FLASH were recently reported as 5-10 Gy, and these must be considered as part of the optimization. Biologists and physicians can use the IBO-IMPT output to investigate individual contributions of each term for preclinical studies and human clinical trials. Different optimization and GPU parallelization algorithms will be discussed as computationally efficient means to provide IBO-IMPT solution. A pixelated proton counting detector can be used to validate the IBO-IMPT solutions and ridge filter assembly design. The detector facilitates measurements of dose, instantaneous dose rate, and LET. Measurements can be further cross validated using a multi-layer strip ionization chamber (MLSIC) and Monte Carlo dose calculation. Validation of instant dose, dose rate and LET will be discussed for various solutions of patient-specific ridge filters, range compensators and proton spot maps provided by IBO-IMPT.

The recorded seminar will be available after the event.