Patients receiving radiation therapy at the Blount Memorial Cancer Center for certain types of cancer now can benefit from image-guided radiation therapy, or IGRT. The new therapy provides clinicians assistance in locating and targeting tumors with a new level of accuracy immediately prior to patients receiving their daily radiation treatment.
“Tumors move between daily radiotherapy treatments due to physiological processes in the body,” said Cancer Center medical director and radiation oncologist Dr. Albert Petty. “Prior to IGRT, we had to take this motion into account by treating a larger margin of healthy tissue around the tumor.” He explained that this technology is the first of its kind, considering the fact it can account for moving tumors.
With the installation of the Varian Medical Systems’ On-Board Imager, which was added to the center’s current linear accelerator through robotically controlled arms, clinicians now have a treatment arsenal that includes a flat panel X-ray image detector and an X-ray tube designed to produce precise, high-resolution X-ray and CT images. Images of the patient’s body are relayed from inside the treatment room to the treatment desk through the image detector and tube, and the robotic arms operate along three axes of motion so they can be best positioned to match the position of the patient’s tumor.
The new addition provides three solid ways to image tumors immediately prior to treatment, according to the center’s staff. First, in radiographic mode, the imager takes separate X-ray images that show detailed bone anatomy. These images are used to calculate exactly how the patient should be moved in 3D space to bring the tumor directly into the path of the treatment beam.
Additionally, in fluoroscopic mode, the new technology generates a moving sequence of images that shows how the tumor moves in time, typically following a patient’s breathing cycle and the up-and-down movements of a patient’s chest. The treatment beam, allowing for this movement, can be rapidly turned on and off automatically, delivering radiation only during needed periods of the patient’s breathing regimen.
In Cone-Beam CT mode, the new advancement generates 3D images that are similar to images from a CT scanner. They’re used for pinpointing soft tissues in the body, such as in the prostate, bladder and certain lung tumors, and then checking for changes in a tumor’s size or position. This information then is matched against images taken during the initial CT scan, which helped to customize the patient’s course of treatment.
“We are showing that we can deliver dosages directly to a tumor – even one that is moving – using IGRT technology,” Petty said. “For outpatients, this will mean fewer side effects from radiation, while actually giving the tumor more dose than before IGRT.” He emphasized that an important patient advantage is the fact that through use of the technology, the radiation beam can be directly targeted to the tumor, which translates to less healthy or normal tissue surrounding the tumor being affected.
Currently, the treatment technology is being used for patients who have prostate, lung and pancreatic tumors, as Petty explained those are the ones that move the most. He added that when explaining a tumor’s movement, it’s not by a large amount – in fact it’s sometimes only a centimeter. But, that’s critical when it comes to positioning the radiation beam.
Medical physicist Mark Wyatt says patients can expect no added discomfort with the technology, only a few extra minutes on the treatment table as the equipment rotates 360 degrees, in a little less than a minute, to pinpoint the tumor’s location in the body.
Good Health Connection holds Heart Month series
In February, Blount Memorial Hospital’s Medical Fitness Center offers participants an 11-part lecture series focusing on heart health for American Heart Month.
• Friday, Feb. 15 from 3 to 4 p.m., cardiovascular surgeon Dr. Thomas Pollard discusses “Open Heart Surgery.”
• Monday, Feb. 18 from 1 to 2 p.m. Blount Memorial pharmacist Rachel Lazim presents “Naturally Healthy Medications.”
• Wednesday, Feb. 20 from noon to 1 p.m., cardiologist Dr. Jane Souther presents “Women and Heart Disease.”
• Friday, Feb. 22 from noon to 1 p.m. MorningView Village assisted living chef Bobbie Aplin offers “Cooking Healthy.”
• Monday, Feb. 25 from noon to 1 p.m. Blount Memorial cardiologist Dr. Philip Hoffman hosts “Questions and Answers,” a session where participants are encouraged to bring questions about heart health, medications and cardiovascular disease.
• Friday, Feb. 29 from 3 to 4 p.m. Fresh Market produce manager Bill Anderson presents “How to Select Healthy Fruits and Vegetables.”
All sessions will be in the Blount Memorial Medical Fitness classroom on the hospital’s 2-east floor and are free to the community. Call Medical Fitness at 865-977-5636 for more information.