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.  

Maria A. Sosa, MD

Board Certified Radiation Oncologist



Dr. Maria A. Sosa received her undergraduate degree at The University of Texas at Austin in biology. She received her medical degree and completed residency training in radiation oncology at The University of Texas Medical Branch at Galveston (UTMB). 


Board certified in radiation oncology, Dr. Sosa has practiced since 2005. Dr. Sosa specializes in Intensity Modulated Radiation Therapy (IMRT), Image Guided Radiation Therapy (IGRT), Stereotactic Body Radiation Therapy (SBRT), Quadramet, and I-131 radioactive iodine ablations for thyroid disease. She is experienced in treating all types of malignancies.


Languages spoken:  English and Spanish  

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.