Despina Katsochi

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/67326

#### **Abstract**

Radiotherapy has an established role in the treatment of cancer and represents a definitive, less invasive approach for various cancer types. Its main aim is to deliver the maximum dose to the tumor with minimal toxicity on neighboring healthy tissues. Therefore, the precise determination of the target and its spatial relation to critical surrounding organs is of main importance. New imaging modalities such as the CT, MRI, and PET/CT offer more anatomical detail and facilitate the accurate delineation of the target volume and the organs at risk. The recent advances in 3D-CRT and IMRT radiation techniques offer high accuracy in tumor targeting and ensure safe dose escalation. Moreover, the introduction of IGRT offers the opportunity to safely apply a supplementary dose to the macroscopic tumor. In trials conducted, a simultaneous integrated boost (SIB) has proved to be feasible in various cancer localizations, to safely increase the total delivered dose, shorten the total treatment time and results in increased tumor control while keeping the side effects low at the same time. However, more trials need to be conducted to establish an acceptable protocol.

**Keywords:** radiation therapy, simultaneous integrated boost, fractionation, radiation dose escalation, image guided radiotherapy
