Choonik Lee is a board-certified therapeutic radiologic physicist by the American Board of Radiology and an authorized medical physicist in High Dose Rate (HDR) brachytherapy by the U.S. Nuclear Regulatory Commission (NRC).

Dr. Lee received his PhD in medical physics from the University of Florida. He completed his post-doctoral residency training in medical physics at the UF Health Cancer Center – Orlando Health (Formerly known as M. D. Anderson Cancer Center Orlando) before he joined the faculty of our department in 2009 as a clinical physicist.

Dr. Lee is actively involved in various clinical services including brachytherapy and image-guided external radiation therapy treatment planning and delivery. He is the lead physicist for a very active ocular brachytherapy program. He is actively involved in federal-funded and corporate-sponsored research projects.

Dr. Lee also serves as an associate director of the department’s medical physics residency program. He is also actively involved in radiation physics education of RTTs and medical residents. His professional affiliations include the American Association of Physicists in Medicine (AAPM), the American Society for Radiation Oncology (ASTRO), and the Radiological Society of North America (RSNA). He is fluent in Korean.

Development of reference pediatric anthropomorphic voxel phantoms

I have developed a series of pediatric anthropomorphic computer models. Before the development, only limited non-standard pediatric models were available. The models have internal organs with reference dimensions that enabled various radiation protection dose estimation studies, such as fluoroscopy, computed tomography, and nuclear medicine. The series was later further enhanced into surface-based phantoms and their voxel representations were accepted as ICRP reference computational models.

1. Lee C, Williams JL, Lee C, Bolch WE. The UF series of tomographic computational phantoms of pediatric patients. Med Phys. 2005 Dec;32(12):3537-48. PubMed PMID: 16475752
2. Lee C, Lee C, Bolch WE. Age-dependent organ and effective dose coefficients for external photons: a comparison of stylized and voxel-based paediatric phantoms. Phys Med Biol. 2006 Sep 21;51(18):4663-88. Epub 2006 Sep 4. PubMed PMID: 16953049
3. Lee C, Lee C, Staton RJ, Hintenlang DE, Arreola MM, Williams JL, Bolch WE. Organ and effective doses in pediatric patients undergoing helical multislice computed tomography examination. Med Phys. 2007 May;34(5):1858-73. PubMed PMID: 17555267
4. Lee C, Lee C, Lodwick D, Bolch WE. NURBS-based 3-D anthropomorphic computational phantoms for radiation dosimetry applications. Radiat Prot Dosimetry. 2007;127(1-4):227-32. Epub 2007 Jun 13. PubMed PMID: 17567763

Assessment of daily and accumulated dose to parotid glands for fractionated radiation treatments

I have developed and implemented a novel framework of daily and accumulated dose assessment for the head and neck patients under fractionated radiation treatment. These types of dose calculations are typically challenging due gradual anatomical change and daily setup errors. By utilizing the daily patient setup CT and treatment couch position information from the Tomotherapy treatment, I was able to show some significant geometric shifts of the parotid glands and subsequent dose deviation, which had not been well understood before. The revelation of the increased dose to the organs at risk under head and neck radiation therapy further increased interests and effort toward the imaged-guided and adaptive radiation therapy in the field.

1. Lee C, Langen KM, Lu W, Haimerl J, Schnarr E, Ruchala KJ, Olivera GH, Meeks SL, Kupelian PA, Shellenberger TD, Mañon RR. Assessment of parotid gland dose changes during head and neck cancer radiotherapy using daily megavoltage computed tomography and deformable image registration. Int J Radiat Oncol Biol Phys. 2008 Aug 1;71(5):1563-71. doi: 10.1016/j.ijrobp.2008.04.013. Epub 2008 Jun 4. PubMed PMID: 18538505
2. Lee C, Langen KM, Lu W, Haimerl J, Schnarr E, Ruchala KJ, Olivera GH, Meeks SL, Kupelian PA, Shellenberger TD, Mañon RR. Evaluation of geometric changes of parotid glands during head and neck cancer radiotherapy using daily MVCT and automatic deformable registration. Radiother Oncol. 2008 Oct;89(1):81-8. doi: 10.1016/j.radonc.2008.07.006. Epub 2008 Aug 15. PubMed PMID: 18707786.

Support of head and neck cancer anatomic and biological image-guided adaptive treatment planning

With the collaboration with other researchers at the University of Michigan, I investigated the treatment planning methods to reduce normal tissue complication for the oropharyngeal HN cancer patients. I have contributed to the study by developing an automatic method of calculating the subvolumes of normal tissues that overlapped with the target volume. I was responsible for calculating the consistently hypo-perfused subvolumes within the GTVs of HNC patients, by applying image registration between pre-treatment and mid-treatment DCE-MRI, as well as supporting all physician contouring and interfacing with image analysts for an adaptive treatment protocol.

1. Samuels S, Eisbruch A, Vineberg K, Lee J, Lee C, Matuszak MM, Ten Haken RK, Brock KK: Methods for reducing normal tissue complication probabilities in oropharyngeal cancer: Dose Reduction or PTV Elimination International Journal of Radiation Oncology*Biology*Physics 96(3): 645-652, 2016.
2. Teng F, Aryal M, Lee J, Lee C, Shen X, Hawkins PG, Mierzwa M, Eisbruch A, Cao Y: Adaptive Boost Target Definition in High-Risk Head and Neck Cancer Based on Multi-Imaging Risk Biomarkers. Int J Radiat Oncol Biol Phys: 2018. PM29428251

3D printed brachytherapy applicators
More recently I have investigated various 3D printed brachytherapy applicators for improved and personalized brachytherapy treatment for ophthalmologic and gynecological cancers.