A prospective pilot study to compare target volume delineation in meningiomas using 68Ga-DOTATATE PET/CT (positron emission tomography/ computed tomography) and current standard of care imaging (MRI)

Intracranial meningioma is one of the most common primary intracranial tumors. It constitutes 10%–15% of all brain neoplasm across the globe, whereas in India, their occurrence varies from 11.6% to 21%. The mainstay of therapy is surgical resection. Adjuvant radiation therapy can be offered for high grade, unresectable, incompletely resected, or recurrent disease. The usage of advanced techniques such as stereotactic radiosurgery and intensity modulated radiation therapy ensures a highly conformal dose to tumour and reduces the dose to surrounding healthy tissues at the same time. The efficacy of these techniques is dependent on accurate target delineation, currently defined by computed tomography (CT) and magnetic resonance imaging (MRI) with gadolinium, the standard for defining disease extent.

However, in infiltrative lesions and in the case of scar formation after surgery or radiation, studies have shown that contrast enhanced MRI imaging may be limited in terms of sensitivity and specificity of diagnosis due to, for example, unspecific contrast enhancement of scar tissue.

Majority of the meningiomas are known to express somatostatin receptor-2 (SSTR2), and with an excellent tumour-to-background ratio, imaging with somatostatin receptor ligands has been established as a method for detection and target volume definition of meningiomas before radiation therapy.

The somatostatin analog DOTATATE has shown high affinity for SSTR2. Labeled with the positron-emitting generator nuclide 68Ga, DOTATATE is increasingly being used for PET investigation of meningiomas, particularly for treatment planning.

This study aims to demonstrate the advantages and disadvantages of incorporating 68Ga- DOTATATE PET/CT for target volume delineation in meningiomas planned for radiation therapy.