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Your Treatment Team

General Surgery

The practice includes a full range of general surgery, endoscopy, laparoscopy, GYN surgery, traumatic orthopedic surgery and limited urologic surgery. Our highly skilled patient-focused team includes two general surgeons, specialty surgeons, three Certified Registered Nurse Anesthetists and surgical nursing staff with years of knowledge and experience.


Heather Osterbrink, MD, FACS

General Surgeon
Heather Osterbrink, MD, FACS (641) 782-3910

Education:

Medical degree, University of Minnesota
Residency at Hennepin County Medical Center, Minneapolis, Minnesota
Board certified in General Surgery

Amy Hynek McFarland, DO

General Surgeon
Amy Hynek McFarland, DO (641) 782-3910

Education:

Mount Ayr High School 2001 & Southwestern Community College, Creston, IA 2001 AA
Graceland University, Lamoni, IA 2003 BA
Creighton University, NE 2004 MS Anatomy
Des Moines University - College of Osteopathic Medicine 2010
Northeast Regional Medical Center, Kirksville, MO 2010-2015
Board certified in General Surgery


Radiation Oncology

In partnership with Mercy Cancer Center of Des Moines, our Greater Regional Cancer Center has a team of six experienced physicians, board certified in radiation oncology, from the top cancer centers in the world. An extensive staff ensures that patients receive individualized treatment planning, therapy and follow-up care.

Richard L. Deming, MD

Radiation Oncologist
rdeming@mercydesmoines.org
Richard L. Deming, MD

Education:

Bachelor of Science degree, South Dakota State University, 1976
Medical degree, Creighton University School of Medicine, 1980
Internship in Internal Medicine, Naval Regional Medical Center, San Diego, 1981
Residency in Radiation Oncology, University of California San Francisco, 1987
Board certified in Radiation Oncology from the American Board of Radiology

Dr. Deming came to Mercy after spending two years on staff at the National Cancer Institute and National Naval Medical Center in Bethesda, Maryland. He also serves as the chairman of the Mercy Cancer Committee. Dr. Deming is active in a number of professional oncology organizations. He is president of the Iowa Society of Therapeutic Radiology. He serves on the Expert Panel for Radiation Oncology for the American College of Radiology. Dr. Deming is on the State Advisory Council of the American Cancer Society and is active in the Iowa Consortium for Comprehensive Cancer Care. He is on the board of directors for the Iowa Oncology Research Association and is the past chairman of the radiation oncology committee for the North Central Cancer Treatment Group. Dr. Deming is a charter member of the Des Moines chapter of the Lance Armstrong LiveStrong Foundation. He is also a Susan G. Komen Society "Doctor for the Cure" and actively supports breast cancer advocacy in Iowa.


Philip J. Colletier, MD

Radiation Oncologist
pcolletier@mercydesmoines.org
Philip Colletier

Education:

Bachelor of Science degree in biology, University of Illinois, Urbana-Champaign, IL, 1985
Medical degree, Rush Medical College, Chicago, 1989
Internship, Letterman Army Medical Center, San Francisco, 1990
Residency in Radiation Oncology, M.D. Anderson Cancer Center, Houston, 1998
Board certified in Radiation Oncology from the American Board of Radiology

Dr. Colletier joined Mercy after completing his residency at the University of Texas MD Anderson Cancer Center in Houston. Prior to his residency, Dr. Colletier served as the chief of ambulatory medicine for the Rock Island Arsenal Health Clinic and as battalion surgeon for the 1st Infantry Division during the Gulf War. He is a member of several organizations including the American Society for Therapeutic Radiology and Oncology, the American Medical Association, the Radiological Society of North America, the Iowa Medical Society, Polk County Medical Society, the North Central Cancer Treatment Group and the Iowa Oncology Research Association. He is the medical director for Mercy Cancer Center Radiation Oncology.


John M. Martens, MD

Radiation Oncologist - Medical Director
jmartens@mercydesmoines.org
John M. Martens, MD

Education:

Doctor of Pharmacy, University of Nebraska Medical Center, 1993
Doctor of Medicine, University of Nebraska Medical Center, 1997
Internship, Iowa Methodist Internal Medicine Residency Program, 1998
Residency, University Hospital in Cincinnati, where he served as chief resident, Radiation Oncology, 2002
Board certified by the American Board of Radiology

Dr. Martens is a member of the American Society for Therapeutic Radiology and Oncology, the Radiologic Society of North America, the American College of Radiology, the American Society of Clinical Oncology, the American Medical Association, the Iowa Medical Society, the Polk County Medical Society, the Iowa Oncology Research Association and the North Central Cancer Treatment Group. Dr. Martens has research background in prostate cancer, lung cancer and trigeminal neuralgia, as well as extensive experience in neuro-oncology and gynecologic oncology.


George H. Voynov, MD

Radiation Oncologist
gvoynov@mercydesmoines.org
George H. Voynov, MD

Education:

Bachelor's degree, Connecticut College, 1996
Medical degree, University of Connecticut, 2001
Internship in Internal Medicine, Thomas Jefferson University, 2002
Residency in Radiation Oncology, University of Pittsburgh, 2006
Board certified by the American Board of Radiology

Dr. Voynov has numerous publications and presentations on the use of Stereotactic radiosurgery and intensity-modulated radiation therapy (IMRT) in optimizing patient outcomes while minimizing side effects of treatment in a wide variety of malignancies. At the University of Pittsburgh, he received specialized training in the use of the CyberKnife®; to treat tumors with high doses of radiation in a single session.

Dr. Voynov is a member of the American Society of Therapeutic Radiation Oncology, the American College of Radiology and actively participates in research trials and protocol reviews through the Iowa Oncology Research Association and the North Central Cancer Treatment Group.


Dev R. Puri, MD

Radiation Oncologist
dpuri@mercydesmoines.org
Dr. Dev Puri, cancer treatment center

Education:

Bachelor's degree, Stanford University, 1994
Medical degree from the University of California, San Francisco, (UCSF) 2002
Residency in Radiation Oncology at Memorial Sloan-Kettering Cancer Center, New York City, 2007
Board certified by the American Board of Radiology

Dr. Puri joined Mercy Cancer Center Radiation Oncology in 2007. Dr. Puri is a member of the American Society for Therapeutic Radiology and Oncology (ASTRO), the American Society of Clinical Oncology (ASCO), the Iowa Medical Society (IMS), the Iowa Oncology Research Association (IORA) and the North Central Cancer Treatment Group (NCCTG) based at Mayo Clinic in Rochester, Minnesota. He is a recipient of the prestigious Patient's Choice Award from vitals.com, a centralized online source of information on doctor performance based on patient feedback. While patient care is his main focus, Dr. Puri has also made many meaningful contributions to the field of radiation oncology as a clinical researcher. He has written on the use of sophisticated radiation techniques designed to maximize both tumor control rates and patients' quality of life, and his work has been published in multiple peer-reviewed medical journals and textbooks. He has collaborated with radiation oncologists from some of the top cancer centers in the world - including the M.D. Anderson Cancer Center, Memorial Sloan-Kettering Cancer Center and the University of California, San Francisco, to develop radiotherapeutic recommendations for specific disease sites. He has more recently served as a peer reviewer for his specialty's premier medical journal, the International Journal of Radiation Oncology, Biology, and Physics (IJROBP). In cooperation with Des Moines University (DMU) Medical School, he has also recently published on the Mercy Cancer Center's experience on the use of CyberKnife Stereotactic Body Radiation Therapy (SBRT) for the treatment of early-stage and recurrent non-small-cell lung cancer. Last year, his work was presented at the annual CyberKnife scientific meeting held in Dallas, Texas and the annual ASTRO scientific meeting held in San Diego, California.


Medical Oncology

Greater Regional Cancer Center has experienced medical oncologist, board certified in Internal Medicine.

Bradley K. Hiatt, DO

Medical Oncologist
(641) 782-3693 Bradley K. Hiatt

Education:

Bachelor's degree, Grandview College, 1991
Medical degree, Des Moines University, 1997
Residency in Internal Medicine at University of Iowa-Iowa Methodist Medical Center, 2000
Fellowship in Medical Oncology and Hematology, University of Iowa Hospitals and Clinics, 2003
Also trained in adult bone marrow and peripheral blood stem cell transplants
Board Certified Internal Medicine, ABIM 2000
Board Certified Medical Oncology, ABIM 2003

Since 2003, Dr. Bradley K. Hiatt has served patients as a Medical Oncologist and Hematologist at Medical Oncology and Hematology Associates in Des Moines, Iowa. Dr. Hiatt will be in Creston at the Greater Regional Cancer Center weekly.

Dr. Hiatt has been honored by the American Osteopathic Medical Association and the Iowa Osteopathic Medical Association with their Service and Achievement awards both in 1997. Dr. Hiatt has published one article on anticoagulation problems.


Brian Freeman, MD

Medical Oncologist
(641) 782-3693 Brian Freeman, MD

Education:

Bachelor's degree, Drake University 1997
Medical degree, Des Moines University, 1997
Residency in Internal Medicine at University of Iowa-Iowa Methodist Medical Center 2008
Fellowship, University of Iowa - Hematology/Oncology 2011

Dr. Brian Freeman serves patients as a Medical Oncologist and Hematologist at Medical Oncology and Hematology Associates in Des Moines, Iowa. Dr. Freeman will be in Creston at the Greater Regional Cancer Center on the first and third Monday of each month.

Dr. Freeman is certified by the American Board of Internal Medicine with specialties in Internal Medicine and Hematology/Oncology.