Transforming an IORT Linac Into a FLASH Research Machine: Procedure and Dosimetric Characterization
G. Felici, Patrizio Barca, Salvatore Barone, Eleonora Bortoli, Rita Borgheresi, Silvia De Stefano, Massimo Di Francesco, Luigi Grasso, S. Linsalata, Daniela Marfisi, M. Pacitti, Fabio Di Martino
Abstract
Since Favaudon's paper of 2014, there has been an increasing interest in FLASH radiotherapy. The FLASH modality could represent a breakthrough in radiation oncology; nevertheless, it brings new scientific and technological challenges. Currently, one of the main limits the scientific community has to cope with is the lack of a common technological platform to experiment with. Considering this framework, the possibility of readapting existing linac platforms to produce a FLASH beam is particularly attractive and different attempts have been already made. The purpose of this article is to illustrate how it is possible to transform a dedicated Intra Operative Radio Therapy (IORT) mobile linac into a FLASH research machine. Compared to the modification required by a standard medical linac, such transformation is easier, does not affect the machine settings and can be rapidly performed by the final user. NOVAC 7 is an IORT linac which can reach a maximum dose-per-pulse up to 13 cGy/pulse (average dose rate 39 Gy/min); such dose rate can be significantly increased by modifying the collimation system. Four different Source Surface Distance (SSD) can be obtained: