The video below illustrates how a lung tumor can move with normal breathing. By using 4-D RT, radiation oncologists can be confident that the tumor receives the full dose of radiation even if the tumor moves with breathing. If you were a sharpshooter, wouldn't you want to know if your target is stationary or if it moves?
![]()
Image gating application enabling you to visualize motion
4-Dimensional Radiation Therapy (4-D RT) is one of the latest advances available in radiation oncology to target tumors that move with breathing. 4-D RT allows the radiation oncologists to track the tumor's motion so that precise radiation can be aimed at the tumor without risking a marginal miss.
![]()
Click here to view demo - 4-Dimensional R-T
Tumors come in many different shapes and sizes. To help determine exactly where to train the beams of radiation during treatment, physicians may perform CAT/CT or MRI scans to produce detailed three-dimensional images of the area being targeted. This preparation process is used in three-dimensional conformal radiotherapy, or 3-D CRT, to minimize the risk of irradiating healthy tissue around the tumor.
Intensity-modulated radiation therapy (IMRT) is a special kind of EBT wherein multiple beams of radiation with varying intensities are focused on all or part of a tumor. Special scans (3-D CT, MRI or PET) and computer-generated dose measurements are used to create a three-dimensional map of the tumor and determine the pattern and intensity of the radiation beams delivered during treatment. IMRT permits more precise targeting of cancerous tissue than traditional radiation therapy, and allows more radiation to be delivered to the tumor with minimal side effects or damage to surrounding healthy cells.
Stereotactic radiosurgery is a kind of EBT used for tumors and lesions in the brain. It is actually not a surgical procedure. Instead, cancer cells are targeted using beams of radiation from special machines (gamma knife, linear accelerator or cyclotron). Accuracy is achieved with the use of three-dimensional computer images and a helmet-shaped device to keep the patient's head in position. Radiation is typically delivered in one session; however, the physician may recommend more than one treatment session, in which case treatment is referred to as stereotactic radiotherapy. Irradiated tumors shrink over the next few months or years.