Wrongs known as right in thyroid scintigraphy and uptake study

Abstract

Objectives: Thyroid scintigraphy using 99m Tc-pertechnetate is commonly used to study function and structure of thyroid gland. Pin-hole collimator is generally preferred in thyroid scintigraphy and uptake studies. The purpose of the present study was to determine actual radiopharmaceutical uptake value in an experimental 99m Tc-pertechnetate thyroid scintigraphy and uptake model. Methods: Thyroid hyperactive and hypoactive nodule models were created using 4 mCi (148 MBq) 99m Tcpertechnetate. In the experimental model, 4 mm, 6 mm and 8 mm diameter pin-hole collimators, and 5 cm, 7 cm and 10 cm object-to-pinhole distances were investigated. Results: In thyroid hyperactive nodule model, despite the same activity value, uptake at 7 cm object-to-pinhole distance was higher compared to 10 cm distance (122% and 103%, respectively). In the patient with Graves' disease, despite the same activity value, uptake at 5 cm object-to-pinhole distance was higher compared to 10 cm distance (8% and 4%, respectively). In thyroid hypoactive nodule model, 4 mm, 6 mm and 8 mm diameters pin-hole collimators were imaged at 5 cm, 10 cm and 15 cm object-to-pinhole distances. The resolution differences between the images were evaluated. Conclusion: It was determined that imaging using 10 cm object-to-pinhole distanceand 4 mm diameter pinhole collimator was best in terms of image resolution and optimum 99m Tc-pertechnetate uptake level.

Türk Bir Popülasyonda Normal Tiroid Teknesyum- 99m Perteknetat Alım Aralığının Belirlenmesi

“…Other important factors for different thyroid uptake measurements are intra-and inter-observer variations and different scintigraphy protocols, as has been reported recently (25). In our study, we compared values in patients from two tertiary hospitals and did not find any significant difference.…”