SPET with thallium-201 ( 201T1) is used in the assessment of brain tumors because the amount of 201T1 accumulated by the tumor cells is proportional to the degree of tumor malignancy, thus making it possible to differentiate high-grade from low-grade gliomas or recurrence from radiation necrosis. Tc 99m sestamibi has been more recently used to study brain tumors. It offers the advantages of Tc 99m labeled molecules including daily availability, good image contrast, low cost and short biological half-life. We studied 20 patients (9 m and 11 f, mean age: 51.3 ± 18 yrs) with histologically proven supratentorial brain tumors (low grade glioma = 4; high grade glioma = 7; radiation necrosis = 2; lymphoma = 1; meningioma = 3; metastasis = 2; histiocytosis = 1) with both the radiotracers (3 mCi of 201Tl and 20 mCi of Tc 99m sestamibi) in the same SPET session (Tomomatic 564, Medimatic; Denmark). All patients underwent MRI or CT scan shortly before the SPET study. The 201Tl and Tc 99m sestamibi uptake were calculated as the ratio between the average counts in a region of interest (ROI) of the tumor and the average counts in a symmetrical ROI in the unaffected hemisphere ( 201Tl and Tc 99m sestamibi indices). The tumor ROI was chosen on the slice showing the maximal tracer uptake. This ROI included all the tissue with tracer uptake higher than 50% of the maximum activity. The Tc 99m sestamibi index was significantly higher than the 201Tl index (2.8 ± 1.3 vs 2.3 ± .86, P =.02 t-paired test). A significant correlation was observed between 201Tl Index and Tc 99m sestamibi indices (y = 1.109x + .244; r = .736, p <.0002). These findings indicate that Tc 99m sestamibi has biological properties in brain tumors similar to those of 201Tl. Its practical advantages encourage a wider clinical application in the study of cerebral neoplasms.
|Number of pages||2|
|Journal||Italian Journal of Neurological Sciences|
|Publication status||Published - 1997|
ASJC Scopus subject areas
- Clinical Neurology