Due to somatostatin receptor expression in meningiomas, PET with somatostatin analogs appears to be useful in radiotherapy treatment planning.
We report the case of a 63-year-old man diagnosed with meningioma of the left frontal lobe in 2011. He underwent total tumor excision (pathology was atypical meningioma WHO 2) and radiotherapy, but one year after the completion of treatment, he complained about diplopia and left upper eyelid ptosis. The MRI showed a new parasagittal lesion and the patient received stereotactic radiotherapy. Few weeks later, two new lesions were found – one in the sella turcica region and the other adjacent to the greater wing of the right sphenoid bone. The patient underwent transsphenoidal biopsy, but was not qualified for neurosurgery due to high risk of bleeding. In the radiotherapy treatment planning, we used a fusion of MRI and 68Ga-DOTA-(Tyr3)-octreotate PET/CT images. The patient received stereotactic radiotherapy, first to the parasellar lesion and then to the progressing tumor adjoining the sphenoid bone. In both cases, PET/CT scans helped to define the target, its volume being bigger on PET/CT than on MRI images.
In patients with meningiomas, 68-Ga-DOTA-(Tyr3)-octreotate PET/CT can be considered as a useful imaging modality in radiotherapy treatment planning, which helps to visualize the tumor extension and to define the target.
Keywords: Meningioma, PET/CT, radiotherapy planning, somatostatin analogs, target definition.