"Tumour sink effect" on the diagnostic or posttreatment radioiodine scan due to sequestration into large-volume functioning metastasis of differentiated thyroid carcinoma influencing uptake in smaller metastatic sites or remnant thyroid tissue: An uncommon but possible phenomenon in thyroid cancer practice.

Two patients of differentiated thyroid carcinoma are illustrated demonstrating "sink effect" in posttherapeutic and diagnostic radioiodine (I-131) study: (a) in the first case, it masked the other small-volume metastatic sites (pulmonary and paratracheal nodes) in the posttreatment scan, which were clarified following metastatectomy of the large-volume skeletal metastatic lesion, and (b) in the second, interestingly, it masked the remnant thyroid uptake in the first postoperative diagnostic radioiodine study. In both the situations, large-volume highly functioning skeletal metastasis was the cause for the observed "sink effect" and is presented as learning illustrations to the attending physicians. Although uncommon, this is a possible phenomenon in thyroid cancer practice.

The feasibility of low-dose oral lithium therapy and its effect on thyroidal radioiodine uptake, retention, and hormonal parameters in various subcategories of hyperthyroid patients: a pilot study.

Background: Radioactive iodine (I) (RAI) is used widely for the treatment of hyperthyroidism either as a first-line treatment or following relapse after antithyroid drug treatment. Intrathyroidal retention of RAI is considered an important determinant of its effectiveness, which is believed to be prolonged by lithium.

Aims And Objectives: To study the impact of low-dose oral lithium therapy on RAI uptake and retention parameters in different subgroups of hyperthyroidism patients, and thus explore its potential role in enhancing the therapeutic efficacy of RAI in these groups of patients.

Thymus uptake of 131I in patients with differentiated thyroid carcinoma: Three different case scenarios and patterns of uptake and the importance of its recognition in thyroid cancer practice.

The importance of recognizing thymic radioiodine uptake as the cause of a false-positive mediastinal focus in the whole-body 131I scan, done for the evaluation of post-thyroidectomy cases of differentiated thyroid carcinoma, is illustrated with the corresponding clinicoradiorological correlation. The pattern of mediastinal uptake could vary based upon the pattern of thymic hyperplasia in an individual case. Three different patterns of mediastinal uptake were observed in the cases described in the present report.

The use of 99mTc-HYNIC-TOC and 18F-FDG PET/CT in the evaluation of duodenal neuroendocrine tumor with atypical and extensive metastasis responding dramatically to a single fraction of PRRT with 177Lu-DOTATATE.

This report describes a case of extensive diffuse bone marrow involvement with bilateral breast metastases from duodenal neuroendocrine tumor giving rise to a superscan-like appearance on somatostatin receptor-targeted (99m)Tc-hydrazinonicotinamide-TOC scintigraphy. The metastatic lesions demonstrated partial concordance with (18)F-FDG PET/CT findings, signifying varying tumor biology and heterogeneity among metastatic lesions in the same individual, as illustrated with a dual-tracer approach. There was a dramatic symptomatic and biochemical response and better health-related quality of life with a single fraction of peptide receptor radionuclide therapy with (177)Lu-DOTATATE, and radiologically there was stable disease at that point.

Comparative evaluation of 24-hour thyroid 131I uptake between γ camera-based method using medium-energy collimator and standard uptake probe-based method.

Unlabelled: The objective of the study was to make a quantitative comparison of 24-h thyroid uptake calculated by γ camera-based and thyroid uptake probe-based methods after administration of a diagnostic (131)I capsule in patients with benign thyroid disorders.

Methods: The study group comprised 66 patients, of whom 26 were male (28-67 y old) and 40 female (20-65 y old). These patients had benign thyroid disorders (primarily hyperthyroidism [thyrotoxicosis]), most of whom had been referred for evaluation before radioiodine treatment.

Examining recombinant human TSH primed ¹³¹I therapy protocol in patients with metastatic differentiated thyroid carcinoma: comparison with the traditional thyroid hormone withdrawal protocol.

Purpose: Recombinant human thyroid-stimulating hormone (rhTSH)-based protocol is a promising recent development in the management of differentiated thyroid carcinoma (DTC). The objectives of this prospective study were: (1) to assess the feasibility and efficacy of the rhTSH primed (131)I therapy protocol in patients with DTC with distant metastatic disease, (2) to perform lesional dosimetry in this group of patients compared to the traditional protocol, (3) to document the practical advantages (patient symptoms and hospital stay) of the rhTSH protocol compared to the traditional thyroid hormone withdrawal protocol, (4) to document and record any adverse effect of this strategy, (5) to compare the renal function parameters, and (6) to compare the serum TSH values achieved in either of the protocols in this group of patients.

Methods: The study included 37 patients with metastatic DTC having lung or skeletal metastases or both.

Dual malignancies in the setting of differentiated thyroid carcinoma: their synchronous or metachronous nature, impact of radioiodine treatment on occurrence of second malignancy and other associated variables.

Purpose: The primary objective of the study was to assess the risk for second primary malignancy after radioiodine treatment for differentiated thyroid carcinoma (DTC). Other objectives were to study the different variables associated with the occurrence of synchronous or metachronous dual malignancies in association with DTC.

Materials And Methods: The patient population studied comprised patients with histopathologically proven DTC referred for radioactive iodine treatment after thyroidectomy followed up at a single centre during the period from January 1963 to March 2011.

The added clinical value of 18F-FDG PET/CT in evaluating intratracheal recurrence of differentiated thyroid carcinoma: implications for planning surgery, assessing its completeness, and planning radioiodine therapy.

In selected patients with differentiated thyroid carcinoma, (18)F-FDG PET/CT has been shown to have added value. We present 2 clinical examples in the settings of both iodine-concentrating and non-iodine-concentrating lesions with tracheal involvement with special reference to its importance in planning of surgery or radioiodine therapy and assessing completeness of surgery. We believe that the use of PET/CT should be considered on a case-by-case basis and specifically when SPECT/CT is unavailable or has inconclusive findings.

A Logical levothyroxine dose Individualization: Optimization Approach at discharge from Radioiodine therapy ward and during follow-up in patients of Differentiated Thyroid Carcinoma: Balancing the Risk based strategy and the practical issues and challenges: Experience and Views of a large volume referral centre in India.

In this communication, the authors discuss the issue of individualization of thyrotropin suppressive therapy in differentiated thyroid carcinoma (DTC) patients and share their views with respect to optimizing the dose of levothyroxine (LT) prescription both during discharge from radioiodine therapy ward and during follow-up. The changing management paradigm at our Institute during post-thyroidectomy period and during the preparation for radioiodine scan is also briefly highlighted. Five factors can be identified as important determinants for the dose individualization approach: (1) Persistence or absence of metastatic disease, (2) the risk characteristics of the patient and the tumor (3) patient's clinical profile, symptomatology, and contraindications (4) the feasibility to ensure a proper thyroid stimulating hormone TSH suppression level (depends on patient's socio-economic and educational background, the connectivity with the local physician and his expertise) (5) time period elapsed since initial diagnosis.

FDG uptake in unilateral breast related to breastfeeding practice in a patient of pulmonary hydatid cyst.

Unusual FDG uptake in unilateral breast on FDG PET study in a 32-year-old lactating woman with recent diagnosis of left upper lobe hydatid cyst is described. The FDG PET study demonstrated uptake in the periphery of the lesion corresponding to the hydatid cyst. In addition, there was an unusually intense FDG tracer uptake in the right breast.

Detection by (18)F-FDG PET of unsuspected extensive bone marrow metastases in a case of basosquamous carcinoma of the cheek.

Basosquamous carcinoma (BSC) is a rare type of malignancy with features of both basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) with a potential for aggressive behaviour infiltration and destruction. First reported by MacCormac in 1910 in a series of rodent ulcers, this entity does have an increased risk of recurrence and metastases as well, which distinguish it from other forms of basal cell carcinoma. The overall incidence of basosquamous carcinoma ranges from 1.

'Reverse discordance' between 68Ga-DOTA-NOC PET/CT and 177Lu-DOTA-TATE posttherapy scan: the plausible explanations and its implications for high-dose therapy with radiolabeled somatostatin receptor analogs.

In this technical note, an unusual discordance between diagnostic and posttherapeutic scan resulting from the use of different somatostatin receptor ligands in two settings is described. Such observation, we believe, is multifactorial, but most importantly arises due to different receptor affinity profile of the ligands and different somatostatin receptor subtype expression in different tumors. It is important for the treating physician to be aware of this phenomenon that would aid in improving our understanding of complex ligand-receptor interactions in various somatostatin receptor-positive tumors with its possible implications for therapeutic decision making with radiolabeled somatostatin receptor analogues.

Bronchoalveolar carcinoma of lung masquerading as iodine avid metastasis in a patient with minimally invasive follicular carcinoma of thyroid.

A 52-year-old man with follicular thyroid carcinoma was administered 182 mCi of radioiodine (I-131) a month after total thyroidectomy. Post-therapy scan revealed diffuse uptake of radioiodine in the apical left lung. CT-guided biopsy of this mass revealed mucinous bronchoalveolar carcinoma.