Positive thyroid cancer scintigraphy using technetium-99m methoxyisobutylisonitrile

Area of Science:

• Nuclear Medicine
• Oncology
• Endocrinology

Background:

• Differentiated thyroid cancer (DTC) requires lifelong monitoring for recurrence.
• Thyroid-stimulating hormone (TSH) suppression is standard therapy, but withdrawal can be challenging for recurrence detection.
• Novel imaging techniques are needed to assess recurrence without treatment interruption.

Purpose of the Study:

• To evaluate the efficacy of technetium-99m sestamibi (99mTc-MIBI) scintigraphy in detecting differentiated thyroid cancer recurrences.
• To assess if 99mTc-MIBI scans can identify metastases without necessitating the withdrawal of thyroid suppressive therapy.

Main Methods:

• A prospective study involving 200 patients with differentiated thyroid cancer treated between 1993 and 1994.
• Administration of intravenous 99mTc-MIBI (500 MBq) followed by upper-body or whole-body scintigraphy 20-30 minutes post-injection.
• Analysis of scan sensitivity, specificity, and predictive values for detecting recurrences in the neck, lungs, and bone.

Main Results:

• 99mTc-MIBI scintigraphy demonstrated very high sensitivity and specificity for detecting bone and lung metastases.
• The predictive value of negative results for distant metastases was very high.
• While sensitivity and specificity for neck lesions were lower, the predictive value of negative neck findings was high.

Conclusions:

• Whole-body scintigraphy using 99mTc-MIBI is a valuable tool for monitoring patients with differentiated thyroid cancer.
• This imaging modality facilitates the detection of distant metastatic lesions without the need to discontinue thyroid suppressive treatment.
• 99mTc-MIBI scans improve the follow-up strategy for DTC patients, particularly for identifying extrathyroidal spread.