Image Guided Radiation Therapy

Image Guided Radiation Therapy (IGRT) with accurate patient positioning and precise dose delivery to the target position are essential in modern clinical workflow for guiding radiation treatment devices. IGRT with three-dimensional image guidance allows precise dose delivery to tumors and reduces the exposure of healthy tissues to unplanned radiation. Tomosynthesis-based 3D image guidance provides in-plane resolution as good as CT and excellent in-depth information with dose levels comparable to a 2D radiograph. Tomosynthesis imaging requires projection images from different viewing angles. Conventional systems use a moving X-ray source to acquire the individual projections. Using the MBFEX technology with the number of beams that equals the number of required projections, this can be achieved without any mechanical motion. Advantages are a faster image acquisition speed, higher spatial and temporal resolution and simple system design.

A square tube array for a tomosynthesis-based IGRT was developed by XinRay together with Siemens Oncology Care Systems. The tube array was designed to be integrated into a Siemens ARTISTE radiation therapy system and attached to the gantry of a medical linear accelerator (LINAC) below the multileaf collimator. The IGRT system utilizes a square-geometry MBFEX tube with 52 individually controllable X-ray beams to acquire projections from multiple angles for rapid tomosynthesis acquisitions without any need to rotate the LINAC gantry. Since the Field Of View (FOV) of the image guidance is in the plane of the treatment isocenter utilizing detector extremities located outside the FOV of the treatment beam, it has the potential to enable simultaneous treatment and imaging for real-time IGRT in most clinical cases, where the treatment target is a small region close to the isocenter. The development won the Sorkin Award from AAPM (American Association of Physicists in Medicine) in 2010.