Glioblastoma (GB) is the most common primary malignant brain tumor in adults. The standard of care consists of maximal possible surgical resection with concomitant radiation therapy (RT) and temozolomide (TMZ). Currently the target volume delineation for RT is based on CT and MRI.
In their study “P04.82 [18F]-FET and [18F]-FAZA PET based radiotherapy of F98 glioblastoma rats” Verhoeven J, Bolcaen J, Donche S, et al, investigate the feasibility of incorporating PET for guiding RT and the impact on treatment outcome by applying subvolume boosting to a [18F]-FAZA or [18F]-FET defined tumor part.
F98 GB cells inoculated in the rat brain were imaged using T2- and contrast-enhanced T1-weighted (CE-T1w) MRI. After tumor growth, a 30 min [18F]-FAZA (2h p.i.) or [18F]-FET (30min p.i.) PET was acquired. Subsequently, a treatment planning CT was obtained on the small animal radiation research platform (SARRP).
They found that despite being very labor-intensive, MRI guided irradiation with PET subvolume boosting is feasible. Based on tumor growth, a significant difference was found between therapy and no therapy. Unfortunately, no significant difference could be observed between the treatment groups. Additional information from molecular imaging techniques enables the visualization of metabolically highly active regions. GB are highly heterogeneous solid tumors, hence the concept of biological target volume and multidimensional conformal RT seems promising.
This Xstrahl In Action was adapted from an article found on a National Library of Medicine website.