'Shine through' on dual tracer parathyroid scintigraphy: a potential pitfall in interpretation

Area of Science:

• Nuclear medicine
• Radiopharmacology
• Endocrine surgery

Background:

• Dual tracer scintigraphy, utilizing Tc-99m sestamibi (MIBI) and Tc-99m pertechnetate, is the preferred method for preoperative parathyroid adenoma localization.
• Standard protocols involve early and delayed MIBI imaging followed by a thyroid-specific pertechnetate scan.

Observation:

• A potential diagnostic challenge arises when intense MIBI retention is observed in the delayed phase.
• This intense focus can obscure interpretation of the subsequent Tc-99m pertechnetate thyroid scan due to a "shine through" artifact.

Findings:

• The "shine through" effect from abnormal MIBI uptake can mimic or mask thyroidal pathology.
• This artifact can lead to misinterpretation, potentially confusing parathyroid adenomas with thyroid adenomas.

Implications:

• To ensure accurate differentiation between parathyroid and thyroid adenomas, repeating the Tc-99m pertechnetate scan on a separate day may be required.
• This strategy helps mitigate the "shine through" artifact, improving diagnostic confidence in preoperative parathyroid imaging.