Peripheral Dosimetry in pediactric craniospinal irradiations

Many different techniques are available for craniospinal irradiations (CSI): electrons and photons irradiation, intensity-modulated radiation therapy (IMRT), field-in-field (FIF), tomotherapy (TT) and 3D conformal radiation therapy (3D-CRT). New technologies allow the dose to be delivered to the tumor with greater precision, improving the survival time - but there are many other factors to be taken into account. For instance, techniques such as IMRT try to optimize the dose delivered to the target organs, but the higher number of beams involved increases the volume of healthy tissues exposed to low doses. On the other hand, other techniques such as tomotherapy require a daily use of imaging throughout the treatment, which may also increase the dose to healthy organs Therefore, from a radioprotection point of view, it is important to assess and compare the out-of-field doses for all the different techniques to see which of them results in lowest doses. For this project, both craniospinal irradiations and imaging for patient positioning have been performed with a clinical linear accelerator in the radiotherapy and radiology department of the academic hospital UZ in Leuven, Belgium.