Quality Assurance Sub-Committee

Meet the Members of the Quality Assurance Sub-Committee

The Radiosurgery Society® (RSS) Physics Quality Assurance Sub-Committee was created to expand and promote RSS efforts related to quality assurance to improve radiosurgery delivery. The RSS and its members benefit tremendously from the guidance and insights of our distinguished members who have years of experience in their specialty and are actively involved in the radiosurgery programs at their own institutions.



Sua Yoo, PhD, DABR


Dr. Yoo is currently an Associate Professor, director of clinical physics, and director of treatment planning at Duke University Medical Center in Durham, North Carolina. After receiving a PhD in Medical Physics from University of Wisconsin, Madison in 2003, Dr. Yoo joined Radiation Oncology Department at Duke University in 2005. Her special focus is on treatment planning & QA, AI clinical implementation, clinical development of SBRT processes.

Paola E. Alvarez, MS

Paola Alvarez, MS, is a medical physicist at IROC Houston QA office within the Radiation Physicist Department at MD Anderson Cancer Center since 2002. She is the scientific lead of the external audit program for output check verification. She is also part of the phantom group dedicated to verification of advance technology external beams treatment in radiotherapy.

She is a member of the American Association of Physicists in Medicine AAPM Task Group 178, Task Group 191, Task Group 235 and Task Group 351. She is IROC representative at the Calibration Laboratory Accreditation Subcommittee at AAPM.

Grace Gwe-Ya Kim, PhD, DABR

Dr. Kim received her doctoral degree in 2001 at Yonsei University in her native Korea. After her graduation, she worked as scientific officer for 7 years in the Medical Device Safety Bureau at the Ministry of Food and Drug Safety in Korea. Dr. Kim completed her post-doc fellowship in the Department of Radiation Oncology at Stanford. She was recruited to join the Department of Radiation Oncology at the UC San Diego in 2009.

She currently serves as a reviewer on American College of Radiation Oncology (ACRO). For the American Association of Physicists in Medicine (AAPM), she is a member of the Calibration Laboratory Accreditation Executive Committee and subcommittee, Task Group 262, Task Group 275, Task Group 292, working group on RO-ILS and a vice-chair of Working Group on Prevention of Errors in Radiation Oncology. Dr. Kim serves as Associate division director for QA and technical chief for Central Nervous System (CNS) and her primary research interests include intracranial radiosurgery and implementing novel treatment techniques. Dr. Kim joined the RSS Physics Committee in February 2017.

Ning Wen, PhD

Ning Wen completed his PhD degree from Wayne State University and MBA from the University of Michigan. Winston has strong interests in many aspects of professionalism in medical physics including clinical care, research and education. He serves as the Director of Clinical Physics at Henry Ford Health System and the Co-director of a stereotactic radiosurgery course at Henry Ford which has trained over 300 clinicians/physicists/therapists in the last five years. He has been a principal investigator on a Research Scholar Grant from the American Cancer Society and a co-investigator on several NIH or industry-funded research grants. His current research interest is to apply supervised and unsupervised machine learning algorithms to analyze omics data derived from medical images and cancer genome for patient risk stratification and treatment response assessment.