In tumours like Diffuse pontine glioma (DIPG), the diagnosis itself spells a death sentence for the child affected. The current standard treatment is conventionally fractionated daily radiation treatment for 6 weeks which benefits 80-90% patients with temporary improvement in neurological function which gives survival up to 8-10 months. With research over several decades, none of the altered fractionation radiotherapy or additional chemotherapy or targeted agents has shown a significant difference in outcomes.~The investigators propose to do an MRI perfusion study in addition to usual MRI at diagnosis and stratify them into hyperperfused or hypoperfused based on the criteria from the investigator's previously published institutional experience in DIPG. The hyperperfused patients will receive additional low dose a drug called Bevacizumab weekly with conventional standard radiotherapy. It is hypothesized that low dose Bevacizumab will decrease hypoxia and improve the efficacy of conventional radiotherapy and in turn improve outcomes.~The hypo-perfused patients will receive ultra-low-dose radiotherapy fractionation equivalent to conventional RT biological dose. As it is assumed that hypoperfused tumours are radioresistant, the investigator hypothesis that the ultra-low dose radiotherapy may overcome that radioresistance as seen in GBM adult patients and may improve outcomes.
In this study, the investigators are testing improvement in survival outcomes in DIPG patients when stratified with MR perfusion score and treated with the said protocol. Newly diagnosed DIPG patients will undergo MRI perfusion study in addition to the usual MRI at diagnosis and will be stratified into hyperperfused or hypoperfused tumours.~The hyperperfused patients will receive additional low dose Bevacizumab weekly with conventional standard radiotherapy.~The hypo-perfused patients will receive ultra-low-dose radiotherapy fractionation equivalent to conventional RT biological dose.