Combined PET/MR imaging using (68)Ga-DOTATOC for radiotherapy treatment planning in meningioma patients.

Hybrid imaging is beneficial for improved medical diagnosis and therapy planning today. Hybrid imaging describes the prospective correlation of two or more complementary sets of imaging information, such as functional and anatomical image volumes. Correlation can be performed through physically combined imaging modalities, such as PET/CT, SPECT/CT, or PET/MR. Here we present first results from employing fully integrated PET/MR tomography for intensity-modulated radiotherapy (IMRT) treatment planning in patients with meningioma using [(68)Ga]-DOTATOC as the biomarker of choice. Combined PET/MR offers higher soft tissue contrast and the ability to add functional information to the plain combination of MR-based anatomy and PET-based metabolic and molecular information. Furthermore, fully integrated PET/MR employs novel PET technology that is neither available in PET-only nor PET/CT systems. Despite the current lack of broad clinical evidence, integrated PET/MR may become particularly important and clinically useful for improved, individualized RT therapy planning for brain lesions. In particular, logistical and diagnostic benefits of integrated PET/MR-based treatment planning over treatment planning based on PET/CT data may be expected in meningioma patients.