Nuclear Imaging


Thallium-201 (201 Tl) single photon emission CT (SPECT) scanning is useful for the evaluation of thymic lesions associated with myasthenia gravis, including lymphoid follicular hyperplasia and thymoma. [12] 
On early images,201 Tl accumulation is more intense in thymomas than in the normal thymus and in lymphoid follicular hyperplasia. On delayed images, uptake is more intense in thymoma and in lymphoid follicular hyperplasia than in the normal thymus. Therefore,201 Tl SPECT scanning can be used to differentiate normal thymus from lymphoid follicular hyperplasia and thymoma in patients with myasthenia gravis.

Degree of confidence

201 Tl uptake is considered to reflect various factors, including cellular metabolic activity, regional blood flow, and the number of viable cells in the lesion; hence,201 Tl imaging is in some respects superior to CT scanning

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