Intraoperative gamma probe detection of head and neck paragangliomas with 111In-pentetreotide: a pilot study

The aim of this study was to assess whether intraoperative radiolocalization of head and neck paragangliomas with 111In-pentetreotide may increase surgical effectiveness, reducing the risk of recurrence.

Our study included eight patients with untreated, recently diagnosed paragangliomas (four unilateral and four bilateral tumors of the carotid body). After i.v. injection of approximation 150 MBq 111In-pentetreotide, preoperative somatostatin receptor scintigraphy (SRS) was performed. SPECT of the neck was performed at four hours and planar images of the head and neck were also obtained at four and 24 hours post injection. Scintigraphy was always compared with the results of conventional imaging methods (MRI, angiography and sonography). Intraoperative detection was performed on 11 lesions 24 hours after radiopharmaceutical administration using a handheld gamma probe.

Preoperative SRS showed high radiotracer uptake in all patients. All the intraoperatively detected lesions were radically resected and histologically confirmed to be involved by tumor. No false positive results were recorded. Gamma probe detection revealed a small intracranial extension not detected by other imaging methods in a patient with a paraganglioma of the right carotid, and partial involvement of the carotid artery in another patient. During follow-up (median 3.5 years; range, 4 months-7 years) all patients remained disease free according to all parameters.

To our knowledge, this is the first experience of radioguided surgery in paraganglioma. Although our study included a relatively small number of patients, we suggest that intraoperative gamma probe detection may be a powerful tool to improve surgical effectiveness.