Our Cancer Care Specialists
- Medical School: Temple University in Philadelphia
- Internship: Crozer Chester Medical Center
- Residency: Radiation Oncology, New York University Medical Center - Two years as Chief Resident
- Board Certification: American Board of Radiology
Won S. Chang, MD, is the Medical Director at Comprehensive Cancer Care in Exton, and joined the staff in July 2000. His clinical areas of expertise include breast cancer as well as cancers of the head and neck, lung, gastrointestinal tract, and prostate.
- Medical School: Tulane University School of Medicine in New Orleans
- Internship: Tulane University
- Residency: New York University Medical Center
- Board Certification: American Board of Radiology
Gregory Ochsner, MD, is a board-certified radiation oncologist. He began practicing radiation oncology at the Exton Cancer Center in 1995, the predecessor to Comprehensive Cancer Care which opened in February 2000. His clinical areas of expertise include head & neck, lung cancers, prostate and gynecologic malignancies.
- Medical School: Jefferson Medical College in Philadelphia
- Internship: Thomas Jefferson University Hospital
- Residency: Thomas Jefferson University Hospital
- Board Certification: American Board of Internal Medicine and the American Board of Radiology-Radiation Oncology
In 1988 Dr. Yelovich joined the Radiation Oncology Department at the Exton Cancer Center, and in 1999 began working on the development of Comprehensive Cancer Care in Exton, which opened in early 2000. Dr. Yelovich has served on the Board of Directors at Brandywine Hospital, the regional American Cancer Society chapter, and numerous physician organizations involved in the improvement of health care and cancer care delivery in Chester County.
Our Cancer Care Technologies
3D Conformal Radiation Therapy
Three-dimensional conformal radiation therapy (3D-CRT) uses computers, CT scans and MRI scans to create detailed, three-dimensional representations of the tumor and surrounding organs. The treatment team uses these images to shape the radiation beams to match the size and shape of the tumor. The tools used to shape the radiation beams are multileaf collimators or custom fabricated heavy metal blocks inserted between the beam and the patient. Nearby normal tissue receives less radiation exposure because the radiation beams are targeted directly at the tumor.
Accelerated Partial-breast Irradiation (APBI)
Accelerated partial breast irradiation (APBI) is high-dose-rate (HDR) internal therapy for breast cancer, administered following a lumpectomy. There are several different applicators including SAVI®, Mammosite®, and Contura®. A radioactive Iridium-192 seed at the end of a metallic wire and contained within a computer-controlled HDR delivery system is directed to 50 or so pre-defined positions within a set of catheters, which are inserted into the lumpectomy site through plastic tubes or a balloon. The HDR delivery system directs the seed sequentially along each catheter tube, stopping at pre-defined dwell positions and delivering radiation along the length of the tube within the lumpectomy site and immediate surrounding area. Treatment is delivered twice a day over five treatment days. After each application, the radioactive seed is withdrawn from the tubes into a lead-lined box and the patient (now non-radioactive) can go home. After the ten treatments are completed, the balloon or catheter array is removed.
CT Scanning & Simulation
Computer Tomography (CT) Scanning & Simulation allows the cancer specialists to design a treatment plan specifically for the patient based on the size, location, and shape of the tumor. The patient will have three-dimensional images (CT Scans) taken. These are used with the treatment planning software that helps determine how to best deliver the radiation beams while reducing damage to surrounding areas. In some cases, it may be necessary to mark the patient’s skin with a tiny marker so that the patient is perfectly realigned in the correct position for every session of radiation therapy. The need for a temporary or permanent marker will be discussed with the patient before the simulation.
Image-Guided Radiation Therapy (IGRT)
Image-Guided Radiation Therapy (IGRT) combines three-dimensional images, such as CT scans, with the precise technology of either 3-D or intensity-modulated radiation therapy (IMRT) to pinpoint and treat cancerous tumors. The images allow the cancer specialists to precisely localize the tumor each time radiation therapy is administered. This improves both accuracy of delivery and safety by reducing radiation exposure to other areas of the body including nearby tissue and organs. IGRT is used to treat tumors in areas of the body that are prone to movement, such as the lungs, liver, and prostate gland, as well as tumors located close to critical organs and tissues.
Intensity-Modulated Radiation Therapy (IMRT)
Intensity-modulated radiation therapy (IMRT) is an advanced form of external radiation treatment that allows precise targeting of tumor cells. The CT simulator localization scan or other three-dimensional images provide the radiation oncologist with an understanding of the shape and location of the tumor. With 3D planning, the radiation oncologist specifies the dose from various beams and sums up those doses to calculate the dose to tumor and normal tissue (forward planning). With IMRT, the radiation oncologist specifies the dose desired to give the tumor and the doses acceptable to the normal tissues (as low as possible). Then the computer system provides millions of alternative beam positions and the varying intensities of each beam, comparing one plan to the next until the best plan is identified. This is called inverse planning. Since each beam is broken up into many sub-beams of varying intensity the process is called intensity-modulated radiation.
Seed Implants (Low Dose Rate Brachytherapy)
Low-dose rate (LDR) brachytherapy delivers radiation using a radioactive device or implant placed inside the body. The device delivers a low dose of radiation to a limited area over a period of 20 to 50 hours. It is one of the most focused, precise forms of radiation therapy and spares much of the surrounding tissue. LDR can be used to treat various cancer sites, such as prostate, uterus, or cervix.
Stereotactic Body Radiation Therapy (SBRT)
Stereotactic body radiotherapy (SBRT), also known as stereotactic ablative body radiation (SABR), is an advanced type of radiation therapy that delivers high doses of radiation using several beams of varying intensity aimed at a very targeted area of the body. Due to the high intensity of the radiation dose, only one to five doses are given over a single day., Treatment can take up to a week and a half when the five treatments are given every other day. Three-dimensional images, such as CT or MRI scans, are used in the simulation process to direct the beams precisely while reducing radiation exposure to other areas of the body. Patients with small, well-defined tumors who cannot tolerate surgery are good candidates for SBRT.
At Comprehensive Cancer Care, we believe that excellent care begins with a skilled and compassionate team of individuals. We have assembled an unmatched team of healthcare professionals dedicated to providing you with the best possible care and services. Your caregiving team consists of a radiation oncologist, radiation therapists, the radiation oncology nurse, medical physicist and a dosimetrist. Each is committed to you as a patient, treating you as family, and ensuring you are supported from diagnosis to recovery.
Your First Appointment
470 John Young Way, Suite 400, Exton, PA 19341
Phone. (610) 524-5550 Fax. (610) 524-5546
Please arrive 15 minutes prior to your scheduled appointment and bring the following:
- Other doctor’s names and phone numbers
- Insurance cards
- Medical history
- List of medications you are currently taking
- Driver’s license, military ID or passport for photo identification
We provide assistance with insurance including pre-authorization, pre-certification for services, and assistance determining benefits. Please call if you have any questions.
The patient portal allows patients to manage their personal health information electronically at their own convenience.