Kirk E. Kanady, MD

Board Certified Radiation Oncologist

 Kirk E. Kanady, M.D graduated Medical School at Northwestern University. He completed his residency in Radiation Oncology at Massachusetts General Hospital, Harvard University, where he also served as Clinical Fellow in Radiation Oncology. Dr. Kanady is board certified in therapeutic radiation oncology. He has extensive experience with the latest techniques for treating cancer, with a particular emphasis in prostate cancer. He is a highly experienced practitioner who has performed over three thousand Prostate Seed Implants (brachytherapy). He is certified for SpaceOAR hydrogel application which improves sexual function and reduces rectal toxicity from prostate radiation.  With over 20 years of experience Dr. Kanady is also an expert in other modalities of Radiation Therapy including intensity modulated radiation therapy (IMRT), image guidance radiotherapy (IGRT) and stereotactic radiosurgery including Stereotactic Ablative Radiation (SABR) for prostate cancer.  Dr. Kanady is the founder and Medical Director of Greater Houston Radiation Oncology which provides professional services to several cancer centers in the Houston area. 


Theodore K. Yang, MD

Board Certified Radiation Oncologist

 Dr. Theodore K. Yang received his undergraduate degree at The University of Texas at Austin in physics and went on to work as a medical physicist before attending medical school. He received his medical degree and completed residency training in radiation oncology at The University of Texas Medical Branch at Galveston (UTMB). He then joined the UTMB faculty specializing in head and neck therapy and brachytherapy.

Board certified in therapeutic radiology, Dr. Yang has practiced radiation oncology Houston since1984.

Dr. Yang is a member of professional medical societies, including the Harris County Medical Society, Texas Medical Association, American Medical Association, ASTRO (American Society for Therapeutic Radiology and Oncology) and CADAH (Chinese American Doctors Association of Houston). 


Maria A. Sosa, MD

Board Certified Radiation Oncologist



Nimi Tuam0kumo, MD

Board Certified Radiation Oncologist

 Nimi Tuamokumo, MD MPH graduated cum laude from Princeton University with a Bachelor of Arts degree in the Psychology. She received her M.D. from Yale University School of Medicine in New Haven, CT and her MPH degree from Harvard School of Public Health. Dr. Tuamokumo completed an internship in the Department of Medicine at Mount Auburn Hospital in Cambridge, MA and a residency in Radiation Oncology at the Harvard Radiation Oncology Program. Dr. Tuamokumo specializes in Intensity Modulated Radiation Therapy (IMRT), Image Guided Radiation Therapy (IGRT), Stereotactic Body Radiation Therapy (SBRT). She is experienced in treating all types of malignancies. Dr. Tuamokumo has been with GHRO since completion of her residency in 2008. She has received many awards, including the National Institutes of Health Careers in Medicine Fellowship, American Cancer Society Outstanding Thesis Award, New England Cancer Society’s Daland Resident Award, NIH Cancer Education Grant, Etta S. Chidsey Award in Cancer Research. Dr. Tuamokumo has published articles and given presentations on a range of topics including breast cancer, prostate cancer, pediatric cancer, and gastric cancer. She is a member of the Texas Medical Association, the American Society of Clinical Oncology, and the American Society for Therapeutic Radiology and Oncology. 


Ather A. Siddiqi, MD

Board Certified Radiation Oncologist

 Dr. Ather A. Siddiqi is a member of ASTRO, BCMS, and TMA.  He attended medical school at the University of Texas Health Science Center in San Antonio; he completed his internal medicine residency at University of Texas Medical Branch in Galveston in 2001.  He then returned to the University of Texas Health Science Center in San Antonio to complete his residency for radiation oncology in 2006.  Dr. Siddiqi is distinguished as one of a small number of doctors who are dual board certified.  Dr. Siddiqi’s comprehensive background as both a radiation oncologist and an internist enables him to provide the highest quality patient care.

Dr. Siddiqi’s main areas of focus are head and neck, lung, breast and prostate cancers.  He provides consultation for patients drawing from a wide range of radiotherapy techniques to produce the best individualized plan for each patient including:  intensity modulated radiation therapy (IMRT),  image guidance radiotherapy (IGRT),  stereotactic radiosurgery, stereotactic body radiation therapy and radiopharmaceuticals to include Zevelin, Quadramet, and  I-131 radioactive iodine ablations for thyroid disease.  Dr. Siddiqi believes in multidisciplinary management and a unified, team-oriented approach to patient care.

Languages spoken:  English, Spanish and Urdu.