Technetium-99m-tetrofosmin for parathyroid scintigraphy: comparison to thallium-technetium scanning

Area of Science:

• Nuclear Medicine
• Endocrinology
• Radiopharmacology

Background:

• Hyperparathyroidism necessitates accurate parathyroid lesion detection for surgical planning.
• Evaluating novel radiotracers is crucial for improving diagnostic accuracy in endocrine surgery.

Purpose of the Study:

• To prospectively assess the efficacy of technetium-99m-tetrofosmin (99mTc-tetrofosmin) for parathyroid lesion detection in patients with hyperparathyroidism.
• To compare the diagnostic performance of 99mTc-tetrofosmin with thallium-201 (201Tl) in identifying abnormal parathyroid glands.

Main Methods:

• Prospective study of 45 patients with primary or tertiary hyperparathyroidism, including those with prior neck surgery.
• Comparison of imaging techniques: 99mTc-tetrofosmin/technetium-99m-pertechnetate subtraction (TF/TC), thallium/technetium subtraction (TL/TC), and single-tracer 99mTc-tetrofosmin washout.
• Quantification of tracer uptake and kinetic analysis using region-of-interest measurements and time-activity curves.

Main Results:

• The TF/TC subtraction technique demonstrated higher overall sensitivity (76%) and accuracy (83%) compared to TL/TC (52% sensitivity, 65% accuracy).
• 99mTc-tetrofosmin showed significantly higher parathyroid-to-thyroid activity ratios than 201Tl (p < 0.001).
• A statistically significant difference in 99mTc-tetrofosmin retention was observed between parathyroid adenomas and hyperplasia (p = 0.005).

Conclusions:

• Technetium-99m-tetrofosmin is a suitable agent for parathyroid imaging in hyperparathyroidism.
• Differential washout protocols based on kinetic properties are not warranted for 99mTc-tetrofosmin in parathyroid and thyroid tissues.
• Further research is needed to elucidate the diagnostic impact of differing 99mTc-tetrofosmin kinetics between parathyroid adenomas and hyperplasia.