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The thyroid and adjacent parathyroid glands demonstrate a variety of benign and malignant pathology, with nodular thyroid disease being the most common pathology encountered in most routine head and neck imaging practice. A variety of thyroid cancers exist, and imaging strategy for staging, surveillance and follow-up depend upon the cancer type. The importance of parathyroid gland imaging in both benign disease, primary hyperparathyroidism (HPT), and the less common parathyroid carcinoma has seen recent advances. An understanding of the available imaging modalities, pathologies and options for imaging thyroid and parathyroid disorders is essential.

The Hybrid Compact Gamma Camera (HCGC) is a small field of view (SFOV) portable hybrid gamma-optical camera intended for small organ imaging at the patient bedside. In this study, a thyroid phantom was used to determine the suitability of the HCGC for clinical thyroid imaging through comparison with large field of view (LFOV) system performance. A direct comparison with LFOV contrast performance showed that the lower sensitivity of the HCGC had a detrimental effect on image quality. Despite this, the contrast of HCGC images exceeded those of the LFOV cameras for some image features particularly when a high-resolution pinhole collimator was used. A clinical simulation showed that thyroid morphology was visible in a 5 min integrated image acquisition with an expected dependency on the activity within the thyroid. The first clinical use of the HCGC for imaging thyroid uptake of 123 I is also presented. Measurements indicate that the HCGC has promising utility in thyroid imaging, particularly as its small size allows it to be brought into closer proximity with a patient. Future development of the energy response of the HCGC is expected to further improve image detectability.

There are many disorders that can occur in the thyroid gland, ranging from benign to malignant entities. This article focuses on 5 common problems of the thyroid that require special consideration with regard to optimizing imaging strategies in a multidisciplinary and collaborative platform. These problems are the incidental thyroid nodule, preoperative evaluation of goiter, hyperthyroidism, invasive thyroid cancer, and recurrent thyroid cancer. For each problem essential facts, interesting updates, imaging approach, and management pearls are reviewed.

Quantitated thyroid scan ( 123 I) of the thyroid nodule: A newmolecular imaging Thyroid nodules are a common clinical finding which often indicates, aside from cancer, a more diffuse disease, such as multinodular goiter, auto-immune thyroid disease or thyroid autonomy. Recent reports suggest that the overall prognosis of thyroid autonomy compares with that of pT2/pT3 thyroid cancer, even in patients with low to normal TSH levels. The thyroid scan (I 123 ) can be quantified, thus offering a powerful tool to diagnose thyroid hyperfunction when local uptake measurements appear innappropriately high as regards to TSH levels. Finally, correlation with ultrasound reduces the number of FNA to suspicious nodules only and optimizes follow-up and specific treatment (lT4, I 131 ) of most benign nodular thyroid diseases.

The two imaging modalities most frequently used in thyroglossal duct cyst (TDC) are thyroid scintigraphy and ultrasound. The imaging is mainly used to exclude the cyst from being the only functioning ectopic thyroid tissue. The main objective of this study is to compare the results of scintigraphy and ultrasound.Methods: A total of 56 patients referred to the National Cancer Institute (NCI), University of Gezira in the period from Jan 2007 to Dec 2009 were included in this study, 30 females and 26 males patients; with median of 12.5 years. Data were analyzed by SPSS software.Results: Both thyroid scintigraphy and ultrasound reached the same imaging findings i.e. 53 patients with TDC and 3 patients with ectopic thyroid tissues. The Fisher exact test revealed no significant difference between the two modalities final results (P- value = 1). In addition, Pearson correlation showed complete correlation between the final ultrasound and scintigraphy results (R2 = 1, P-value < 0.0001). Furthermore, ultrasound has provided detailed cyst characterization.Conclusion: Both modalities revealed almost identical results. Ultrasound has the additional advantages of being non-ionizing radiation and accurately localizes and characterizes the TDC.Keywords: thyroid scan, thyroid ultrasound.

99mTc pentavalent dimercaptosuccinic acid [99mTc(V) DMSA], a useful agent for imaging thyroid medullary carcinoma and other tumors can be reliably prepared by addition of Na99mTcO4 to a freeze-dried mixture of DMSA and Sn (2:1 molar ratio). The radiochemical purity, stability and animal bio-distribution behaviour is similar to that of the agent made by addition of NaHCO3 to DMSA (III) renal imaging freeze-dried kit.

99m Tc pentavalent dimercaptosuccinic acid [ 99m Tc (V) DMSA], a useful agent for imaging thyroid medullary carcinoma and other tumors, can be reliably prepared by addition of NaHCO 3 and then Na 99m TcO 4 to a commercial kit for 99m Tc trivalent DMSA [ 99m Tc (III) DMSA], followed by bubbling oxygen through the solution for 10 min. 99m Tc (V) DMSA made by this method is radiochemically pure and stable for 24 h, and it gives a rat biodistribution similar to that of the agent made by previous methods. Clinical biodistribution and radiation dosimetry studies are planned.

We correlated scintigraphy and histological findings in 40 cases of nodular goiter in which two or more kinds of scintigraphy were performed preoperatively. 201Tl scintigraphy for imaging thyroid carcinoma showed a diagnostic agreement of 80% for thyroid lesions and 82% for metastatic lesions in the cervical lymph nodes. These agreements were higher than with 99mTc-bleomycin scintigraphy. Thus, 201Tl scan can be used to evaluate 'cold' thyroid nodules and to visualize metastatic lesions. 201Tl scan was also found valuable as a diagnostic measure for local recurrence of thyroid carcinoma. However, there were a few false-positive and false-negative results.