Objective: To investigate the utility of intraoperative 99mTc-sestamibi radioguidance (hand-held gamma probe) for diagnosis and detection of cervical hyperplastic parathyroid glands in renal-induced hyperparathyroidism patients.

Material and Method: A prospective analytical study was conducted between March 2014 and March 2015. Thirty-three end stage renal failure patients were included in the present study. All patients were intravenously administered 99mTc-sestamibi prior to surgery and underwent bilateral neck exploration. After suspected parathyroid tissues were identified, the hand-held gamma probe was used to quantify the surgical area, which was reported as four values, thyroid counts, in vivo counts of suspected tissue, ex vivo counts of suspected tissue, and surgical bed counts. The first interesting parameter (criterion 1) is the radioactivity ratio, which was calculated as a function of ex vivo radioactivity versus surgical bed radioactivity and expressed as a simple percentage. The second interesting parameter (criterion 2) is the differences between in vivo radioactivity and thyroid radioactivity. All specimens were sent for pathological study as a gold standard for diagnosis. The experimental protocol was approved by the Ethical Committee of Rajavithi Hospital (No. 041/2557).

Results: One hundred twenty nine specimens were excised of which 119 were hyperplastic parathyroid glands. The means of the radioactivity from in vivo hyperplastic parathyroid tissues were significantly higher than those in non-parathyroid tissues (1,133.29 cps vs. 688.30 cps, p = 0.001). The means of the radioactivity from ex vivo hyperplastic parathyroid tissues were significantly higher than those in non-parathyroid tissues (469.11 cps vs. 167.10 cps, p = 0.003 respectively). The sensitivity, specificity, and the accuracy for predicting hyperplastic parathyroid tissue by using a 20% cut-off point of radioactivity ratio (criterion 1) were 95.00%, 70.00%, and 93.00% respectively. The area under the curve from the ROC curve was 0.83 (95% CI = 0.65, 1.00). The sensitivity, specificity, and accuracy for predicting hyperplastic parathyroid tissue by using greater than 100 cps gap of the difference between in vivo radioactivity and thyroid radioactivity (criterion 2) were 81.70%, 60.00%, and 80.00% respectively. The area under the curve from the ROC curve was 0.81 (95% CI = 0.69, 0.92). Using the parallel calculation method, the sensitivity increased to 98.30%. Using the serial calculation method, the specificity increased to 80.00% for prediction.

Conclusion: The hand-held gamma probe can be used to identify hyperplastic parathyroid glands with high sensitivity by using criteria 1. Moreover, the researcher believes that the other radioactivity calculation (criterion 2) is a quick and helpful tool for screening intraoperative questionable lesions. Finally, the results show that the probe’s sensitivity can be enhanced by using parallel method calculation between the two criteria and its specificity can be enhanced by using serial method calculation.

Keywords: Hand-held gamma probe, Radioguided parathyroid surgery, Parathyroidectomy, Renal-induced hyperparathyroidism