  The challenge of removing cancerous cells lies in the limitation of organ at
risk, which restricts the ability to increase the radiation dose adequately for
enhancing treatment effectiveness. This survey provides a comprehensive
overview of the 4{\pi} planning technique for radiation therapy. In radiation
therapy, the gantry of Medical linear accelerators can rotate around the couch
to administer radiation from various angles. Researchers have introduced the
4{\pi} technique with the objective of increasing the radiation dose to tumors
while minimizing damage to nearby organs. While dose escalation may not be
feasible in certain cases due to potential complications in normal tissues, the
4{\pi} technique enables dose escalation for certain types of cancers. The
optimization problem formulation constitutes a major innovation in the 4{\pi}
technique. In this survey, we went thorough optimization problem of 4{\pi}
technique and discussed about the available investigations that have been
performed on 4{\pi} technique.

Medical Physics