Grid radiation therapy, using the megavoltage X-ray beam, has been proven to be an effective method for management of large and bulky malignant tumors. This treatment modality is also known as Spatially Fractionated Radiation Therapy (SFRT). In this treatment technique a grid block converted the open radiation field into a series of pencil beams. It is based on the concept of delivering non-uniform, high dose, pencil beam radiation through a collimated grid with a 50:50 open to closed blocked area ratio. The grid dose distribution is similar to stereotactic “virtual” brachytherapy.