Physics of Image-guided
Radiation Therapy
Most of the above research outcomes are certainly of potential use in CBCT for IGRT. Additionally, we have conducted more directly relevant researches for IGRT in clinical settings. Dose evaluation due to CBCT is considered an important issue particularly for pediatric patients and/or repeated daily CBCT scanning situations. We have evaluated and validated the imaging organ dose in the GATE simulation environment by integrating XCAT human phantom in the package (J. Clin. Med. Phys. 2014 - Son, Rad. Prot. Dosimet. 2016). In an attempt to reduce imaging dose in daily CBCT, we proposed a region-of-interest imaging technique (J. Clin. Med. Phys. 2014 - Lee) and a tube-current modulation technique (PlosOne 2018 - Son).
Motion estimation of the moving target in radiation therapy is essential for both gated radiotherapy and tracking radiotherapy. Using a CBCT system mounted in linac treatment machine, we have successfully implemented a marker trajectory reconstruction based on interdimensional correlation modeling in collaboration with our colleagues in Asan Medical Center (Med. Phys. 2016). Associated 4D dose calculation has also been evaluated (PlosOne 2018 -Chung). In hadron therapy, it is critically important to validate the hadron range in-vivo and to estimate dose distribution accordingly. We are actively developing a novel image reconstruction technique for such purposes using an in-beam time-of-flight PET scanner in collaboration with Prof. Kao at the University of Chicago.
