1Division of Nuclear Medicine, Institute of Nuclear Medicine and Allied Sciences (INMAS), Lucknow Road, Delhi-110054
2Department of Cytopathology, Institute of Nuclear Medicine and Allied Sciences (INMAS), Lucknow Road, Delhi-110054
3Department of CT & Ultrasound, Institute of Nuclear Medicine and Allied Sciences (INMAS), Lucknow Road, Delhi-110054
The aim of this study was to find out if thyroid nodules can be characterised on the basis of retention of 99mTc-Tetrofosmin and whether preoperative evaluation of malignancy is possible using this method.
We prospectively evaluated 21 patients (15 males and 6 females) with solitary thyroid nodules which were cold on 99mTc pertechnetate scintigraphy to evaluate the diagnostic value of 99mTc-Tetrofosmin scintigraphy. Single injection dual phase (30 min and 120 min)thyroid scintigraphy using15 mCi of 99mTc-Tetrofosmin was performed in all these patients using LEAP collimator in a gamma camera. Images were analysed using ROI software to assess target to background ratio at 30 min and 120 min. In the following days and weeks all the patients underwent surgery. Outcome of the nodules was ascertained with histopathological examination in all the cases.
All the 21 patients showed increased uptake of tracer in the thyroid nodule, with rest of the gland showing normal uptake, at 30 min.5 out of 6 patients of thyroid carcinoma showed increased uptake in the thyroid nodule, both at 30 min and 120 min, with normal washout in rest of the gland.12 out of 15 benign nodules showed a significant washout of radiotracer at 120 min as compared to 30 min image.
The sensitivity and specificity of this modality for detection of malignant nodules was found to be 83.3% and 80% respectivily.
Delayed washout pattern of 99mTcTetrofosmin scintigraphy is a useful parameter for preoperative characterization of solitary thyroid nodules.
