Hitting the target — and nothing else
Posted by Esther Fabian : October 8th, 2009
Dr. Ishmael Parsai
I recently celebrated passing the halfway point of my 33 days of radiation for breast cancer, so I thought this would be a good opportunity to share with you the process of radiation treatment planning.
Dr. Ishmael Parsai is professor and chief of medical physics and director of UT’s graduate medical physics program. I asked him to be a guest writer on my journal about the process:
Before patients actually begin their radiation treatment, they come to our clinic to start what is affectionately called the “patient simulation day”, where imaging data is acquired and patient’s skin is carefully marked to map out the area being treated. With the patient secured in treatment position, CT images are acquired and transferred to our treatment planning computers for target identification and treatment plan analysis. The section of the anatomy imaged is reconstructed in 3D space, and through careful measurements the best angles for aiming the radiation beams to treat the target while sparing healthy tissue are determined. If additional imaging (MRI, SPECT, or PET) is deemed necessary, those are also sent to treatment planning computers for image fusion, and further analysis to make certain that the affected area is delineated. Beam ports are also identified with tiny marks on skin (like a tattoo), to help the radiation therapist precisely position the patient for daily treatments. The patient is asked to come back a few days later where work is done to generate an optimized treatment plan. A final treatment plan is then reviewed and approved by a radiation oncologist. We may go through a few iterations to achieve that final plan which gets transferred to the treatment machines and quality checked to get it ready for treatment day. Quality assurance is a major part of radiation treatment performed by the medical physicists on every patient to assure high level of accuracy. In most of the breast treatment cases, we deliver a daily fraction (up to five weeks) to a larger area encompassing the affected site and some related lymphatics. This is followed by 14 to 17 additional days of daily radiation concentrated on the area where the tumor was found. When delivering the boost radiation, the radiation oncologist focuses the radiation field on the tumor bed to assure that all the microscopic cancer cells are sterilized. The daily treatment takes about 15 minutes from beginning to end.
It is interesting to note that based on 2008 statistics from the American Cancer Society’s Facts and Figures publication, breast cancer is the most common type of cancer in American women. This year alone, 182,000 women and 2,000 men will learn they have breast cancer. Another 68,000 women will learn they have noninvasive (also called in situ) breast cancer. What most people do not realize is that breast cancer can often be cured. About 80 percent of all patients with breast cancer live 10 years after their diagnosis.
Esther Fabian is the director of health care marketing at The University of Toledo. Although she is a graduate of Bowling Green State University, Esther has willingly traded in brown and orange for the blue and gold. Over her nine years of employment at the institution, she continues to be fascinated by the incredible things that UT Medical Center professionals do every day to help people and loves learning about the many aspects of health care through those exceptional people. Esther hopes to use this journal to give folks a peek into the world of UT Medical Center, and maybe an occasional glimpse into the world of a working mom and owner of many, many pets.
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