Visualization of internal motion within a treatment portal during a radiation therapy treatment

We offer a method for visualization of treatment portals continually during a radiation therapy treatment. Using digital image processing in conjunction with a fluorescent screen, portal images are obtained almost instantly. Images of quality that are clinically useful can be visualized every second. Digital enhancement further improves the quality of the images. The availability of instant portal images before each treatment can be most helpful in verifying that the patient is correctly and precisely set up prior to the onset of radiation. The ability to visualize treatment portals continuously during a treatment can help to ensure that radiation is restricted to the prescribed field and is not altered significantly by patient motion. In this report, we show and discuss a sequence of instant portal images obtained during a single treatment in which motion and absence of motion of internal anatomy is clearly demonstrated.