Our Faculty: Physicians and Physicists

At Stony Brook Medicine, experienced radiation oncologists work with other members of the Radiation Oncology team to treat patients with cancer. The team uses a wide range of radiation therapies and advanced techniques-all with the goal of killing cancer cells and sparing healthy tissue from damage. 

 

Samuel Ryu, MD
Professor and Chair,  Radiation Oncology, and Deputy Director, Clinical Affairs, Stony Brook Cancer Center

Board Certification: Radiation Oncology 

Language (other than English): Korean
Recognition: America’s Top Doctors, 2005 to present (Castle Connolly) and Top Doctors List from Hour Detroitmagazine, 2005 to 2013; America’s Top Oncologists of Consumers’ Research Council of America, 
2006 to present

Specialty: Brain and Spine cases, Benign tumors, Head and Neck cancers

Personal Statement: I am at the forefront of high technology radiosurgery of brain and spine tumors. I give my constant effort to compassionate use of these treatments for my patients. I try to be on the patient's perspective and care about the patient's well-being.

For more information about Dr. Ryu, click here 
View Video: Pushing Radiosurgery to the Edge

Mark Ashamalla, MD 
Clinical Assistant Professor, Radiation Oncology

Board Certification: Radiation Oncology 

Medical School:  Sidney Kimmel Medical College at Thomas Jefferson University in Philadelphia

Internal Medicine Internship: Albany Medical Center jointly with the Albany Stratton Veteran's Hospital

Residency: New York-Presbyterian Brooklyn Methodist Hospital

Specialty: Treatment of thoracic, gynecologic, and head and neck cancers using advanced treatment techniques including stereotactic radiosurgery (SRS), stereotactic body radiotherapy (SBRT), and high dose-rate (HDR) brachytherapy. Through clinical care, resident education, and research, his goals are to improve long-term outcomes for his patients by improving efficacy, minimizing toxicity, ensuring treatment value and affordability, and exploring the potential synergies of radiation therapy with immunotherapy, all within a patient-centered treatment approach and clinical trials.

Meet Our Doctor Video: Dr. Mark Ashamalla

Kartik Mani, MD, PhD
Clinical Assistant Professor, Radiation Oncology 

Board Certification: Radiation Oncology

Medical School: Albert Einstein College of Medicine, Bronx, NY
Residency: St. Luke's-Roosevelt Hospital Center, New York, NY

Residency: Montefiore Medical Center, Bronx, NY

Specialty: Lung Cancer, Head and Neck Cancer, Gastrointestinal Cancer, Prostate Cancer, Brain Tumor, Stereotactic Body Radiotherapy (SBRT), Biomedical Information

Meet Our Doctor Video: Dr. Kartik Mani
CancerWise Smart Talk Video on Lung Cancer: Presented by Dr. Kartik Mani

Alexander Slade, MD. PhD
Clinical Assistant Professor, Radiation Oncology

Board Certification: Radiation Oncology 

Medical School: the University of Illinois with an MD and PhD (focused on health economics)

Residency: Virginia Commonwealth University in Richmond, VA

Specialty: I primarily see patients with genitourinary cancers, especially prostate cancer. My practice involves both external beam radiation therapy (including Stereotactic Body Radiation Therapy) as well as high dose rate (HDR) brachytherapy. I feel privileged to be able to work with other members of the Stony Brook Cancer Center team to be able to offer a full range of treatments for patients facing prostate cancer. My research interests include clinical topics related to prostate cancer radiotherapy, the role of radiation therapy on normal tissue injury, as well as health services research related to long-term radiation toxicities among cancer survivors.

CancerWise Smart Talk Video on genitourinary cancer, including prostate cancer: Presented by Dr. Alexander Slade

 

Alexander M. Stessin, MD, PhD
Assistant Professor, Radiation Oncology 

Board Certification: Radiation Oncology  

Medical School: Rockefeller University, Sloan-Kettering Institute, and Weill Cornell Medical College; MD and Ph.D. in medicine/pharmacology from tri-institutional MD/Ph.D. program
Residency: New York-Presbyterian 
Hospital/Weill Cornell Medical College; transitional year residency at St. Vincent's Medical Center, Bridgeport, CT; Radiation Oncology

Specialty: Gastrointestinal Cancers, Breast Cancers, Brain and Child Tumors

For more information about Dr. Stessin, click here
View Video: Pushing Radiosurgery to the Edge

 

Edward Valentine, MD
Clinical Assistant Professor,  Radiation Oncology 

Board Certification: Radiation Oncology 

Language (other than English): French
Medical School: New York Medical College
Residency: Memorial Sloan-Kettering Cancer Center, Radiation Oncology
Fellowship: Memorial Sloan-Kettering Cancer Center, Radiation Oncology

Specialty: Women's Cancers, Leukemia and Lymphomas, Head and Neck Cancers

For more information about Dr. Valentine, click here 

View Video: External Beam Radiation Therapy, Presented by Edward Valentine, MD

 

Clare M. Moran, DNP, FNP, RN
Family Nurse Practitioner, Radiation Oncology

Board Certification: Family Nurse Practitioner

Doctor of Nursing Practice: Stony Brook University Master of Science in Nursing

Family Nurse Practitioner: Columbia University Bachelor of Science in Nursing: Binghamton University

 

Bruce Demple, PhD

Ph.D., Biochemistry, University of California, Berkeley

B.A. Biology, Wesleyan University

For most of my career, I have been investigating cellular pathways that cope with free radical stress and oxidative DNA damage.  Many of the same pathways act in response to ionizing radiation, and our work helps reveal how these mechanisms influence the cellular effects of radiation, with potential application to radiotherapy.    

 

 Tiezhi Zhang, Ph.D, DABR

Medical Physicist  

Professor and Director of Medical Physics

Radiation Oncology, School of Medicine

Research Interest

Novel x-ray source development, distributed x-ray system for imaging and radiation treatment, FLASH-RT, proton imaging and quality assurance. My current research focused on the development of novel x-ray imaging systems based on distributed x-ray sources and proton FLASH-RT QA.  

Education

PhD, Medical Physics, University of Wisconsin, Madison, WI  2004

MS, Physics, Drexel University, Philadelphia, PA, 1999

BS, Physics, Jilin University, Chuangchun, China, 1994

Publications

A list of publications can be found HERE

Contact Information

Office  (631) 444-3617

Email  tiezhi.zhang@stonybrookmedicine.edu  

Stony Brook University Hospital

Department of Radiation Oncology

Hospital Level 2, Room 660

Stony Brook, NY 11794-8460 

 

 Jinkoo Kim, Ph.D, DABR 

Medical Physicist, Radiation Oncology & Clinical Associate Professor, School of Medicine 

Research Interest

Biomedical image registration and segmentation for advanced radiotherapy modalities – My expertise lies in oncologic image analysis, focusing on applications for radiation therapy (such as SRS, SBRT, and adaptive RT). My current research centers on developing AI-based algorithms for medical image registration and segmentation to address ongoing challenges in radiation therapy

Education

PhD, Electrical and Computer Engineering, Wayne State University, MI, 2007

MS, Electrical and Computer Engineering, Wayne State University, MI, 2001

MS, Electronic Engineering, Sungkyunkwan University, Seoul, Korea, 1998

BS, Electronic Engineering, Sungkyunkwan University, Seoul, Korea, 1995

Publications

A list of publications can be found HERE.  

Contact Information

Office  (631) 444-8298

Email  Jinkoo.kim@stonybrookmedicine.edu  

Stony Brook University Hospital

Department of Radiation Oncology

Hospital Level 2, Room 648

Stony Brook, NY 11794-8460 

Xin Qian, PhD, MBA, DABR
Medical Physicist & Clinical Assistant Professor

Research Interest

I have spent significant amount of time on translational research:

Radiopharmaceutical dosimetry study

AI based image reconstruction

Medical device design and development

Education

MBA, Stony Brook University, 2023

Residency, Medical physics, Columbia University, 2014

Post Doc, Medical physics, University of North Carolina, Chapel Hill, 2011

PhD, Optical Physics, Bournemouth University, UK, 2008

BSc. Physics, Tianjin University, 2004

Publications (Selected from 60+ peer reviewed papers and proceedings)

X. Qian, Ziyu Shu, Salar Souri, Yizhou Zhao, Zhaozheng Yin, Renee Farrell, Jinkoo Kim, Jieying Wu, Sam Ryu, Tiezhi Zhang: Dual-Source Cone-Beam CT for HDR Brachytherapy In-Suite Imaging: Simulation Studies of Limited Angle Image Reconstruction based on Deep Image Prior. Brachytherapy, 2025 (in process).

X. Qian, Dejan Trbojevic, Samuel Ryu: Spread Out Bragg-Peak FLASH Proton Beams by Permanent Magnet Synchrotron for SRS and SBRT. JRSBRT, 2025

R. Vasyltsiv, X. Qian (co-first author), S. Ryu, W. Zhao. and A. Howansky, Feasibility of 4D HDR brachytherapy source tracking using x‐ray tomosynthesis: Monte Carlo investigation. Medical Physics, 50(8), pp.4695-4709, 2023

Jason Qin, Lindsay Puckett, X. Qian, Image Based Fractal Analysis for Detection of Cancer Cells, IEEE Bioinformatics and Biomedicine, 49941. 9313176, 2020

X. Qian, and J. Adamovics, Performance of an improved first generation optical CT scanner for 3D dosimetry, Phys. Med. Biol. 58, N321–N331, 2013.

X. Qian, R. Rajaram, X. Calderon-Colon, T. Phan, O. Zhou: Design and Characterization of a Spatially Distributed Multi-Beam Field Emission X-ray Source for Stationary Digital Breast Tomosynthesis, Medical Physics, 36 (10), 4389-4399, 2009. (This article is selected for Virtual Journal of Nanoscale Science & Technology, 20 (12), 2009.The Virtual Journal is an edited compilation of links to articles from participating publishers, covering a focused area of frontier research.) 

Contact Information

Stony Brook University Hospital, Department of Radiation Oncology

Stony Brook, NY 11794 

 

Renee Farrell, Ph.D, DABR 

Medical Physicist &  Clinical Assistant Professor

Research Interest

My current research interests include artificial intelligence for oncologic applications, including radiomics and deep learning projects. I am also involved in research studies investigating the ability of Raman spectroscopy to be used for tissue classification.

Education

PhD, Biomedical Engineering, Stony Brook University, NY, 2020

BA, Philosophy, Stony Brook University, NY, 2014

Publications

A list of publications can be found HERE. 

Contact Information

Office  (631) 216-9087

Email  Renee.Farrell@stonybrookmedicine.edu

Stony Brook University Hospital

Department of Radiation Oncology

Stony Brook, NY 11794-8460 

An Ting Hsia, MS
Radiation Oncology, Medical Physicist

Board Certification: Therapeutic Radiologic Physics 

Specialty: Image-Guided Radiation Therapy, SRS/SRT/SBRT Treatment