Abstract
It's well-known that a radiotherapy should be done, Based on the correct patient setup at the planning and on the accurate sighting a radiation shooting beam to tumor targets in human body.
In general, the irradiation field will be determined by the X-ray simulator referring clinical images, e.g. radiograph, CT's, MRI's, etc.
Nowadays, EPID (which stands for Electronic Portal Imaging Device) has been installed in the oncology institutions, by that the fluoroscopic monitoring images would be displayed to check the patient setup mobilization during radiotherapy.
However, there's still room for doubt in the correct localization, i.e., therapists and oncologists judge the irradiation field size, that was localized by the materials of EPID and graph of LINAC, with the subjective naked eyes.
So we tried to collate localization image with images of DSA, MRI and CT as reference, and collate portal image with localization film with machinery. When we collate, problems of image distortion and geometric magnification on each modalities have occurred.
To solve these problems, we composed correction table for image distortion, and led automatic verification for a quantitative analysis of irradiation field. For this system, we could provide high precision of radiation therapy.
