The role of dynamic phase pertechnetate scanning in thyroid malignant disease

The use of 99m-biphasic technetium pertechnetate thyroid scintigraphy entails the recording of a rapid series of dynamic images immediately following the bolus injection of the tracer. Thereafter static images are recorded 10-20 minutes later with a pin-hole collimator. A significant increase in perfusion seen during the dynamic phase of the study in an area which is 'cold', i.e. absent uptake on static images, is considered as indicative of malignant disease. This phenomenon of perfusion/uptake mismatch is attributed to increased vascularity of the tumour, but decreased tracer uptake by the dedifferentiated cancerous cells. A retrospective study was conducted to test this hypothesis, and it is concluded that the perfusion phase of thyroid imaging may provide useful clinical information regarding possible malignant disease in a goitre.