Objectives In radiation therapy, the field-in-field (FIF) technique is used to prevent administration of unnecessarily high doses reduce toxicity. Recently, FIF has been for whole brain irradiation (WBI). Using technique, volume that receives a higher than prescribed dose (hotspot) can be largely reduced; however, treatment planning requires time. Therefore, burden on planners, we propose semia...

Background: An effective method for management of large and bulky malignant tumors. This treatment modality is also known as Specially Fractionated Radiation Therapy (SFRT). In this treatment technique a grid block converted the open radiation field into a series of pencil beams. Dosimetric characteristics of an external beam grid radiation field have been investigated using experimental and Mo...