[The first experience in using radionuclude by single-photon emission computed tomography in the diagnosis of orbital neoplasms].

The scintigraphic study using 99mTc-labeled red blood cells was performed in 3 steps in 18 patients with an orbital space-occupying lesion. Patients with orbital cavernous hemangiona were found to have decreased accumulation of the agent in a vascular phase, as well as intensive hyperfixation at planar scintigraphy and single-photon emission computed tomography. Intensive accumulation of the agent in the involved region was observed in patients with malignancies at dynamic, delayed scintigraphy and single-photon emission computed tomography. Only the follow-up revealed the agent's hyperfixation in a patient with squamous-cell carcinoma of the lower lid skin with its spread to the orbit. None of the stages of a scintigraphic showed any accumulation of labeled red blood cells in a patient with orbital fibroma and in a patient with cranioorbital meningioma. Thus, the characteristic differentially diagnostic signs of benign and malignant orbital neoplasms were revealed.